doi:10.1007/s00376-017-7092-4

Ackerman A. S., O. B. Toon, D. E. Stevens, A. J. Heymsfield, V. Ramanathan, and E. J. Welton, 2000: Reduction of tropical cloudiness by soot.Science288,1042-1047,https://doi.org/10.1126/science.288.5468.1042.10.1126/science.288.5468.1042

6021863ab1dad74ba0db14715d4ddd03

http%3A%2F%2Fwww.jstor.org%2Fstable%2F10.2307%2F3075107%3Fsearch%3Dyes%26amp%3Bresultitemclick%3Dtrue%26amp%3Bsearchtext%3Dau%3A%26amp%3Bsearchtext%3D%22j.%2520welton%22%26amp%3Bsearchuri%3D%252faction%252fdobasicsearch%253fymod%253dyour%252binbound%252blink%252bdid%252bnot%252bhave%252ban%252bexact%252bmatch%252bin%252bour%252bdatabase.%252bbut%252bbased%252bon%252bthe%252belements%252bwe%252bcould%252bmatch%25252c%252bwe%252bhave%252breturned%252bthe%252bfollowing%252bresults.%2526amp%253bquery%253dau%253a%252522j.%252bwelton%252522%2526amp%253bsi%253d1

http://www.sciencemag.org/cgi/doi/10.1126/science.288.5468.1042

Anderson T. L., S. J. Masonis, D. S. Covert, N. C. Ahlquist, S. G. Howell, A. D. Clarke, and C. S. McNaughton, 2003: Variability of aerosol optical properties derived from in situ aircraft measurements during ACE-Asia.J. Geophys. Res.,108(D23),8647,https://doi.org/10.1029/2002JD003247.10.1029/2002JD003247

c1b3eec2dfe4bbb99a6da1eb2efa2e83

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2002JD003247%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2002JD003247/full[1] Airborne measurements of aerosol light scattering (using nephelometers) and absorption (using particle/soot absorption photometers; PSAPs) in the Asian outflow region are presented. Aerosol particles were sampled through a new low turbulence inlet that proved very effective at transmitting coarse-mode particles. Noise and artifacts are characterized using in-flight measurements of particle-free air and measurements with identical instruments operated in parallel. For example, the sensitivities of PSAP noise to changing altitude, changing relative humidity (RH), and particle-loading on the internal filter are quantified. On the basis of these and previous instrument characterizations, we report averages, variations, and uncertainties of optical properties, focusing on data from approximately 300 level-leg samples obtained during 19 research flights in the spring of 2001. Several broad patterns emerge from this analysis. Two dominant components, fine-mode pollution and coarse-mode mineral dust, were observed to vary independently when separated using a cut point of 1 0204m aerodynamic diameter at low RH. Fine-mode pollution was found to be moderately absorbing (single scatter albedo at low RH and 550 nm, 0309 = 0.88 00± 0.03; mean and 95% confidence uncertainty) and moderately hygroscopic (relative increase in scattering from 40% to 85% RH, fRH = 1.7 00± 0.2), while coarse-mode dust was found to have very low absorption (0309 = 0.96 00± 0.01) and to be almost nonhygroscopic (fRH = 1.1 00± 0.1). These and other optical properties are intended to serve as constraints on optical models of the Asian aerosol for the purpose of satellite retrievals and calculations of direct radiative effects.

Andreae M. O., O. Schmid, H. Yang, D. Chand , J. Z. Yu, L.-M. Zeng, and Y.-H. Zhang, 2008: Optical properties and chemical composition of the atmospheric aerosol in urban Guangzhou,China.Atmos. Environ.,42,6335-6350,https://doi.org/10.1016/j.atmosenv.2008.01. 030.10.1016/j.atmosenv.2008.01.030

364f576c1ccdb3ddfe19ffd3ed10030e

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS135223100800071X

http://linkinghub.elsevier.com/retrieve/pii/S135223100800071XDuring the Pearl River Delta measurement campaign (Program of Regional Integrated Experiments of Air Quality over Pearl River Delta 2004, PRIDE-PRD2004, 4 October–5 November 2004), we measured aerosol light absorption and scattering (PM2.5) in urban Guangzhou, using a photoacoustic spectrometer and two integrating nephelometers (at ambient and dry humidity). In addition, 12-h averages of elemental carbon (EC a ), organic carbon (OC), and inorganic species concentrations were determined. Aerosol concentrations in urban Guangzhou were extremely high, with average PM2.5, OC, and EC a concentrations of 103, 22.4, and 7.102μg02m 613 , respectively. The chemical composition of the aerosol was dominated by particulate organic matter, EC a , sulfate and ammonium. Elevated levels of potassium indicated significant contributions from biomass burning to the regional haze. The high average OC/EC a ratio of 3.6±1.1 resulted from a mixture of regional haze with high OC content and local emissions with low OC/EC a , mostly from vehicular sources. The average scattering and absorption coefficients for dry aerosol were 418 and 9102Mm 611 ( λ 6554002nm), and the mean mass scattering and absorption efficiencies 4.2±1.0 and 0.78±0.1902m 2 02g 611 . During some episodes resulting from the trapping of local emissions in a nocturnal boundary layer, extreme values of aerosol absorption were reached (up to 49002Mm 611 ). The average single scattering albedo ( ω 0 , λ 6554002nm) at dry conditions was about 0.83, representing a mixture of fresh, strongly absorbing, urban pollution, and a more scattering regional haze. Because of the prevailing low humidity, the ambient ω 0 was not significantly higher. The mass absorption efficiency of EC a was 7.702m 2 02g 611 ; an additional contribution to absorption was associated with OC, either as a result of light absorption by OC or the effects of internal mixing. The observed diurnal trends of the optical and chemical properties are consistent with aged regional haze dominating during mid-day, enhanced traffic activity in the morning and evening hours, and the build-up of a shallow nocturnal boundary layer during night.

gström, A., 1964: The parameters of atmospheric turbidity. Tellus, 16( 2), 64- 75.10.1111/j.2153-3490.1964.tb00144.x

092c490380deec24acc6ee53937e4666

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F305114171_The_Parameter_of_Atmospheric_Turbidity

http://onlinelibrary.wiley.com/doi/10.1111/j.2153-3490.1964.tb00144.x/pdfThe methods for evaluating the atmospheric turbidity parameters, introduced by the present author in 192909000930, are subjected to a critical examination. A method first suggested by M. Herovanu (1959) is here simplified and expanded, and used for deriving the named parameters in adherence to a procedure described by the present author in a previous paper in this journal (1961). The procedure is applied to the pyrheliometric observations at Potsdam in 193209000936, published by Hoelper (1939) A comparison between the frequency distribution of the coefficient of wave-length dependence 02± at the high level station Davos and the low level station Potsdam gives results which are discussed in detail. In all the figures of the present paper, where the turbidity coefficients occur, they are multiplied by 103.

Behnert I., V. Matthias, and R. Doerffer, 2007: Aerosol climatology from ground-based measurements for the southern North Sea.Atmos. Res.,84,201-220,https://doi.org/10.1016/j.atmosres.2006.05.006.10.1016/j.atmosres.2006.05.006

cf0de288e3a6e33df67acc6f45c2bef3

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0169809506001827

http://linkinghub.elsevier.com/retrieve/pii/S0169809506001827An aerosol climatology over the southern North Sea region has been set up using aerosol optical properties derived from regular sunphotometer (AERONET) and lidar (EARLINET) measurements between April and September for the years 2000–2003. Data from four AERONET sites in the North Sea coastal region (Helgoland Island, Oostende, Hamburg and Lille) and, for comparison purposes, also from two “maritime sites” (Rame Head and Azores Island) are selected. The variability of the aerosol optical depth τ a(500) and 02the spatial distribution of aerosol optical depth τ a(500), 03ngstr02m wavelength exponent02 α 4406187002, as well as of retrieved microphysical aerosol parameters (single scattering albedo, index of refraction, particle size distribution) are studied. The 402years of observations show great similarities between the North Sea coastal sites and Helgoland Island. Although 7002km separated from the coast, the aerosol optical properties found at the island are much closer to those at Hamburg, Oostende and Lille than at the maritime sites Rame Head and Azores. Compared to the standard aerosol models differences in the 03ngstr02m wavelength exponent02 α 4406187002, the single scattering albedo and the refractive index are detected. Based on these observations a new aerosol model for the atmospheric correction of coastal water reflectance spectra of the imaging spectrometer MERIS/ENVISAT was set up, which meets in particular the higher 03ngstr02m wavelength exponent of the coastal sites compared to standard maritime conditions.

Bokoye A. I., A. Royer, N. T. O'Neill, P. Cliche, G. Fedosejevs, P. M. Teillet, and L. J. B. McArthur, 2001: Characterization of atmospheric aerosols across Canada from a ground-based sunphotometer network: AEROCAN.Atmos.-Ocean39,429-456,https://doi.org/10.1080/07055900.2001.9649687.10.1080/07055900.2001.9649687

9e7ac22a3ebdf0439f7a66dbc06c2723

http%3A%2F%2Fwww.tandfonline.com%2Fdoi%2Fabs%2F10.1080%2F07055900.2001.9649687

http://www.tandfonline.com/doi/abs/10.1080/07055900.2001.9649687Ground090006based sunphotometry measurements acquired under clear sky conditions can be used to investigate atmospheric aerosol optical properties. Such measurements are not only important in their own right as a technique for monitoring generic aerosol dynamics, but also represent a direct means of evaluating the contribution of aerosol induced radiative forcing in the modelling of climate change. In this paper we analyze derived aerosol optical properties using datasets from the Canadian AEROCAN (AERosol CANada) sunphotometer network.

Cao J. J., S. C. Lee, K. F. Ho, X. Y. Zhang, S. C. Zou, K. Fung, J. C. Chow, and J. G. Watson, 2003: Characteristics of carbonaceous aerosol in Pearl River Delta Region, China during 2001 winter period. Atmos. Environ., 37, 1451-1460, https://doi.org/10.1016/S1352-2310(02)01002-6.

Cao J. J., S. C. Lee, K. F. Ho, S. C. Zou, K. Fung, Y. Li, J. G. Watson, and J. C. Chow, 2004: Spatial and seasonal variations of atmospheric organic carbon and elemental carbon in Pearl River Delta region,China.Atmos. Environ.,38,4447-4456,https://doi.org/10.1016/j.atmosenv.2004.05. 016.10.1016/j.atmosenv.2004.05.016

f1d4252f54cd24f60afb9044c2d8ff85

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231004004923

http://linkinghub.elsevier.com/retrieve/pii/S1352231004004923The concentrations of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were investigated at eight sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of the Pearl River Delta Region (PRDR), China, during winter and summer 2002. The comparison of summer and winter results was made in order to investigate spatial and seasonal variations. PM 2.5 and PM 10 samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed by the thermal optical reflectance (TOR) method following the Interagency Monitoring of PROtected Visual Environments (IMPROVE) protocol. During summer, the average OC and EC concentrations in PM 2.5 were 9.2 and 4.1 μg m –3, while those in PM 10 were 12.3 and 5.2 μg m –3. Carbonaceous aerosol accounted for 38.0% of the PM 2.5 and 32.9% of the PM 10. The daily average OC, EC, PM 2.5 and PM 10 concentrations in PRDR were higher in winter than in summer. The average OC/EC ratio was 2.5 for PM 2.5 and PM 10, suggesting the presence of secondary organic aerosols. The estimated secondary organic carbons in PM 2.5 and PM 10 were 4.1 and 5.6 μg m –3, respectively. The OC and EC were found to be correlated in winter (correlation coefficient r=0.82) and summer ( r=0.64), which implied that motor vehicle sources contributed to the ambient carbonaceous particles. The distribution of eight carbon fractions in OC and EC at eight sites was first reported in ambient samples in Asia, which also indicated that motor vehicle exhaust was the dominant contributor to carbonaceous particles.

Chameides, W. L., Coauthors H, 1999: Case study of the effects of atmospheric aerosols and regional haze on agriculture: An opportunity to enhance crop yields in China through emission controls? Proc.Natl. Acad. Sci. U. S. A96,13 626-13 633,https://doi.org/10.1073/pnas.96.24.13626.10.1073/pnas.96.24.13626

10570123

f57df6f2ce67c90000afb13a7b199fe9

http%3A%2F%2Fwww.jstor.org%2Fstable%2F121272

http://www.pnas.org/cgi/doi/10.1073/pnas.96.24.13626The effect of atmospheric aerosols and regional haze from air pollution on the yields of rice and winter wheat grown in China is assessed. The assessment is based on estimates of aerosol optical depths over China, the effect of these optical depths on the solar irradiance reaching the earth's surface, and the response of rice and winter wheat grown in Nanjing to the change in solar irradiance. Two sets of aerosol optical depths are presented: one based on a coupled, regional climate/air quality model simulation and the other inferred from solar radiation measurements made over a 12-year period at meteorological stations in China. The model-estimated optical depths are significantly smaller than those derived from observations, perhaps because of errors in one or both sets of optical depths or because the data from the meteorological stations has been affected by local pollution. Radiative transfer calculations using the smaller, model-estimated aerosol optical depths indicate that the so-called "direct effect" of regional haze results in an approximately 5-30% reduction in the solar irradiance reaching some of China's most productive agricultural regions. Crop-response model simulations suggest an approximately 1:1 relationship between a percentage increase (decrease) in total surface solar irradiance and a percentage increase (decrease) in the yields of rice and wheat. Collectively, these calculations suggest that regional haze in China is currently depressing optimal yields of approximately 70% of the crops grown in China by at least 5-30%. Reducing the severity of regional haze in China through air pollution control could potentially result in a significant increase in crop yields and help the nation meet its growing food demands in the coming decades.

Che H., G. Shi, A. Uchiyama, A. Yamazaki, H. Chen, P. Goloub, and X. Zhang, 2008: Intercomparison between aerosol optical properties by a PREDE sky radiometer and CIMEL sunphotometer over Beijing,China. Atmos. Chem. Phys., 8, 3199-3214, https://doi.org/10.5194/acp-8-3199-2008.10.5194/acp-8-3199-2008

2a99c5c03f092e97be35efc4761a5903

http%3A%2F%2Fcpfd.cnki.com.cn%2FArticle%2FCPFDTOTAL-BJQX201106001018.htm

http://cpfd.cnki.com.cn/Article/CPFDTOTAL-BJQX201106001018.htmhis study compares the aerosol optical and physical properties simultaneously measured by a SKYNET PREDE skyradiometer and AERONET/PHOTONS CIMEL sunphotometer at a location in Beijing,China.Aerosol optical properties(AOP) including the Aerosol Optical Depth (AOD),Angstrom exponent(),volume size distribution, single scattering albedo() and the complex refractive index were compared.The difference between the two types of instruments was less than 1.3%for the AOD and less than 4%for the single scattering albedo below the wavelength of 670 nm.There is a difference between the volume size distribution patterns derived from two instruments,which is probably due to difference of measurement protocols and inversion algorithms for the respective instruments. AOP under three distinct weather conditions(background, haze,and dust days) over Beijing were compared by using the retrieved skyradiometer and sunphotometer data combined with MODIS satellite results,pyranometer measurements, PM_(10) measurements,and backtrajectory analysis. The results show that the significant difference of AOP under background,haze,and dust days over Beijing is probably due to different aerosol components under distinct weather conditions.

Che, H., Coauthors, 2014: Column aerosol optical properties and aerosol radiative forcing during a serious haze-fog month over North China Plain in 2013 based on ground-based sunphotometer measurements.Atmos. Chem. Phys.14,2125-2138,https://doi.org/10.5194/acp-14-2125-2014.10.5194/acp-14-2125-2014

e051582973681ddeab4b01abc2a4b15f

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2014ACP....14.2125C

http://www.atmos-chem-phys.net/14/2125/2014/In January 2013, North China Plain experienced several serious haze events.Cimel sunphotometer measurements at seven sites over rural, suburban andurban regions of North China Plain from 1 to 30 January 2013 wereused to further our understanding of spatial-temporal variation of aerosoloptical parameters and aerosol radiative forcing (ARF). It was found thatAerosol Optical Depth at 500 nm (AODsub500 nm/sub) during non-pollution periodsat all stations was lower than 0.30 and increased significantly to greaterthan 1.00 as pollution events developed. The Angstrom exponent (Alpha) waslarger than 0.80 for all stations most of the time. AODsub500 nm/sub averagesincreased from north to south during both polluted and non-polluted periodson the three urban sites in Beijing. The fine mode AOD during pollutionperiods is about a factor of 2.5 times larger than that during thenon-pollution period at urban sites but a factor of 5.0 at suburban andrural sites. The fine mode fraction of AODsub675 nm/sub was higher than80% for all sites during January 2013. The absorption AODsub675 nm/sub atrural sites was only about 0.01 during pollution periods, while~0.03–0.07 and 0.01–0.03 during pollution and non-pollutionperiods at other sites, respectively. Single scattering albedo variedbetween 0.87 and 0.95 during January 2013 over North China Plain. The sizedistribution showed an obvious tri-peak pattern during the most seriousperiod. The fine mode effective radius in the pollution period was about0.01–0.08 μm larger than during non-pollution periods, while thecoarse mode radius in pollution periods was about 0.06–0.38 μm lessthan that during non-pollution periods. The total, fine and coarse modeparticle volumes varied by about 0.06–0.34 μmsup3/sup, 0.03–0.23 μmsup3/sup, and 0.03–0.10 μmsup3/sup, respectively, throughout January2013. During the most intense period (1–16 January), ARF atthe surface exceeded 6150 W msup612/sup, 61180 W msup612/sup, and 61200 W msup612/sup at rural, suburban, and urban sites, respectively. The ARFreadings at the top of the atmosphere were approximately 6130 W msup612/sup inrural and 6140–60 W msup612/sup in urban areas. Positive ARF at the top of theatmosphere at the Huimin suburban site was found to be different from othersas a result of the high surface albedo due to snow cover.

Che, H., Coauthors, 2015: Ground-based aerosol climatology of China: Aerosol optical depths from the China Aerosol Remote Sensing Network (CARSNET) 2002-2013.Atmos. Chem. Phys.15,7619-7652,https://doi.org/10.5194/acp-15-7619-2015.10.5194/acp-15-7619-2015

cb8abb30c062422dadb79ba179a739bf

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2015ACP....15.7619C

http://www.atmos-chem-phys.net/15/7619/2015/Long-term measurements of aerosol optical depths (AODs) at 440 nm and ngstrm exponents (AE) between 440 and 870 nm made for CARSNET were compiled into a climatology of aerosol optical properties for China. Quality-assured monthly mean AODs are presented for 50 sites representing remote, rural, and urban areas. AODs were 0.14, 0.34, 0.42, 0.54, and 0.74 at remote stations, rural/desert regions, the Loess Plateau, central and eastern China, and urban sites, respectively, and the corresponding AE values were 0.97, 0.55, 0.82, 1.19, and 1.05. AODs increased from north to south, with low values (< 0.20) over the Tibetan Plateau and northwestern China and high AODs (> 0.60) in central and eastern China where industrial emissions and anthropogenic activities were likely sources. AODs were 0.200.40 in semi-arid and arid regions and some background areas in northern and northeastern China. AEs were > 1.20 over the southern reaches of the Yangtze River and at clean sites in northeastern China. In the northwestern deserts and industrial parts of northeast China, AEs were lower (< 0.80) compared with central and eastern regions. Dust events in spring, hygroscopic particle growth during summer, and biomass burning contribute the high AODs, especially in northern and eastern China. The AODs show decreasing trends from 2006 to 2009 but increased ~ 0.03 per year from 2009 to 2013.

Che, H. Z., Coauthors, 2009a: Instrument calibration and aerosol optical depth validation of the China Aerosol Remote Sensing Network.J. Geophys. Res.,114,D03206,https://doi.org/10.1029/2008JD011030.10.1029/2008JD011030

28db0712acdc3c077916fc348a73c81e

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2008JD011030%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2008JD011030/pdfThis paper introduced the calibration of the CE-318 sunphotometer of the China Aerosol Remote Sensing Network (CARSNET) and the validation of aerosol optical depth (AOD) by AOD module of ASTPWin software compared with the simultaneous measurements of the Aerosol Robotic Network (AERONET)/Photom茅trie pour le Traitement Op茅rationnel de Normalization Satellitaire (PHOTONS) and PREDE skyradiometer. The results show that the CARSNET AOD measurements have the same accuracy as the AERONET/PHOTONS. On the basis of a comparison between CARSNET and AERONET, the AODs from CARSNET at 1020, 870, 670, and 440 nm are about 0.03, 0.01, 0.01, and 0.01 larger than those from AERONET, respectively. The aerosol optical properties over Beijing acquired through the CE-318 sunphotometers of one AERONET/PHOTONS site and two CARSNET sites were analyzed on the basis of 4-year measurements. It was obvious that the AOD of the Shangdianzi site (rural site) was lower than that of the two urban sites (the Institute of Atmospheric Physics (IAP) site (north urban site) and the Beijing Meteorological Observatory (BJO) site (south urban site)). The AOD of BJO was about 0.05, 0.04, 0.05, and 0.06 larger than that of IAP at 1020, 870, 670, and 440 nm, respectively, indicating that there is more local pollution in the south part of Beijing. The highest AOD was found in summer because of the stagnation planetary boundary layer and transport of pollutants from large pollution centers south of Beijing. The high temperature and relative humidity in summer also favor the production of aerosol precursor and the hygroscopic growth of the existing particles locally, which results in high AOD. In contrast, the lowest AOD at the two urban sites and one rural site in Beijing occurred in winter as the frequent cold air masses help pollutants diffuse easily.

Che H. Z., X. Y. Zhang, S. Alfraro, B. Chatenet, L. Gomes, and J. Q. Zhao, 2009b: Aerosol optical properties and its radiative forcing over Yulin,China in 2001 and 2002.Adv. Atmos. Sci.,26(4),564-576,https://doi.org/10.1007/s00376-009-0564-4.

10.1007/s00376-009-0564-4

62cb37300396c7175d2781c750f8a8d0

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs00376-009-0564-4

http://link.springer.com/10.1007/s00376-009-0564-4The aerosol optical properties and direct radiative forcing over the Mu Us desert of northern China, acquired through a CE318 sunphotometer of the ground-bascd Aerosol Robotic Network (AERONET), are analyzed. The seasonal variations in the aerosol optical properties are examined. The effect of meteorological elements (pressure, temperature, water vapor pressure, relative humidity and wind speed) on the aerosol optical properties is also studied. Then, the sources and optical properties under two different cases, a dust event and a pollution event, are compared. The results show that the high aerosol optical depth (AOD) found in Yulin was mostly attributed to the occurrence of dust events in spring from the Mu Us desert and deserts of West China and Mongolia, as well as the impacts of anthropogenic pollutant particles from the middle part of China in the other seasons. The seasonal variation and the probability distribution of the radiative forcing and the radiative forcing efficiency at the surface and the top of the atmosphere are analyzed and regressed using the linear and Gaussian regression methods.

Cheng, Y. F., Coauthors, 2008: Aerosol optical properties and related chemical apportionment at Xinken in Pearl River Delta of China.Atmos. Environ.,42,6351-6372,https://doi.org/10.1016/j.atmosenv.2008.02.034.

10.1016/j.atmosenv.2008.02.034

c83f813ee1cb74adeed218d132c229e2

http%3A%2F%2Fnew.med.wanfangdata.com.cn%2FPaper%2FDetail%3Fid%3DPeriodicalPaper_JJ025799293

http://linkinghub.elsevier.com/retrieve/pii/S1352231008001854Aerosol optical properties (AOPs) of sub- 10 μ m mathContainer Loading Mathjax particles under dry conditions (relative humidity (RH) <20% < 20 % mathContainer Loading Mathjax ) were investigated at Xinken in Pearl River Delta of China from 4 October to 5 November 2004. Severe aerosol optical pollution has been found characterized by strongly light-absorbing particles. At 55002nm, the magnitude of the light scattering ( 333 ± 138 Mm - 1 mathContainer Loading Mathjax ) and absorption ( 70 ± 42 Mm - 1 mathContainer Loading Mathjax ), limited visual range ( 5.3 ± 2.5 km mathContainer Loading Mathjax ), and low single scattering albedo ( 0.83±0.05 0.83 ± 0.05 mathContainer Loading Mathjax ) show Xinken to be comparable to the most polluted urban cores rather than even a polluted rural site. Other presented AOPs include hemispheric backscattering fraction ( 11±1% 11 ± 1 % mathContainer Loading Mathjax ) and asymmetry parameter ( 0.67±0.01 0.67 ± 0.01 mathContainer Loading Mathjax ) at 55002nm, and 03ngstr02m exponent ( a 08 450 / 700 = 1.6 ± 0.15 mathContainer Loading Mathjax ). Systematic relationships exist among the various AOPs. Their diurnal variations cannot be solely explained with the development of atmospheric boundary layer, but also obviously influenced by local wind patterns, variation of sources, photochemistry and nighttime heterogeneous chemistry. The fractional contributions to extinction, scattering and absorption ( f ep ; sp ; ap f ep ; sp ; ap mathContainer Loading Mathjax ) due to sub-aerosol-populations and individual chemical compounds are derived by the Mie simulations. The sub- 1 μ m mathContainer Loading Mathjax particles contribute more than 90% of the particle extinction ( σ ep , 550 nm mathContainer Loading Mathjax ). Under dry conditions, f ep f ep mathContainer Loading Mathjax of non-sea-salt sulfate, particulate organic matter, elemental carbon (EC) and residual are about 44%, 17%, 17% and 15%, respectively. However, the water uptake of particles can contribute 50–60% to σ ep , 550 nm mathContainer Loading Mathjax at RH 90%. So in the ambient atmosphere, sulfate, carbonaceous material and water all play very important roles, concerning the visibility impairment at Xinken. The respective mass extinction, scattering and absorption efficiencies ( α ep ; sp ; ap α ep ; sp ; ap mathContainer Loading Mathjax ) are mostly consistent with previously reported values for the polluted area. α ap , EC , 550 nm mathContainer Loading Mathjax for sub- 1 μ m mathContainer Loading Mathjax and sub- 10 μ m mathContainer Loading Mathjax ranges are 9.3±1.4 9.3 ± 1.4 mathContainer Loading Mathjax and 7.2 ± 1.0 m 2 g - 1 mathContainer Loading Mathjax , respectively. Our results imply a higher α ap , EC α ap , EC mathContainer Loading Mathjax for more internally mixed EC under the atmospheric conditions present at Xinken.

Clarke A., V. Kapustin, 2010: Hemispheric aerosol vertical profiles: Anthropogenic impacts on optical depth and cloud nuclei.Science329,1488-1492,https://doi.org/10.1126/science.1188838

10.1126/science.1188838

20847262

08053d2d95075f56e9aeab6408ccdda2

http%3A%2F%2Feuropepmc.org%2Fabstract%2FMED%2F20847262

http://www.sciencemag.org/cgi/doi/10.1126/science.1188838Abstract Understanding the effect of anthropogenic combustion upon aerosol optical depth (AOD), clouds, and their radiative forcing requires regionally representative aerosol profiles. In this work, we examine more than 1000 vertical profiles from 11 major airborne campaigns in the Pacific hemisphere and confirm that regional enhancements in aerosol light scattering, mass, and number are associated with carbon monoxide from combustion and can exceed values in unperturbed regions by more than one order of magnitude. Related regional increases in a proxy for cloud condensation nuclei (CCN) and AOD imply that direct and indirect aerosol radiative effects are coupled issues linked globally to aged combustion. These profiles constrain the influence of combustion on regional AOD and CCN suitable for challenging climate model performance and informing satellite retrievals.

Corrigan C. E., V. Ramanathan, and J. J. Schauer, 2006: Impact of monsoon transitions on the physical and optical properties of aerosols.J. Geophys. Res.,111,D18208,https://doi.org/10.1029/2005JD006370.10.1029/2005JD006370

3886a75fa6ec66eabda3f679b27a557e

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2005JD006370%2Ffull

http://doi.wiley.com/10.1029/2005JD006370[1] Project Atmospheric Brown Cloud (ABC-Asia) has focused on measuring the anthropogenic influence of aerosols, including black carbon, to determine the extent of sunlight dimming and radiative forcing over the Asian region. As part of this project, an observatory was built in the Republic of Maldives for the long-term monitoring of climate. An inaugural campaign was conducted to investigate the influence of the shifting monsoon seasons on aerosols and climate change. The presence of black carbon and other anthropogenic aerosols over the Indian Ocean varies with the cyclic nature of the Indian Monsoon. Roughly every 6 months, the winds change directions from southwest to northeast or vice versa. From June to October the wet monsoon brings clean air into the region from the Southern Hemisphere. Conversely, the dry monsoon brings polluted air from the Indian subcontinent and Southeast Asia from November through April. As a result, the region becomes charged with black carbon and other anthropogenic pollutants during the dry monsoon. In 2004 the transition between the clean and polluted seasons resulted in nearly an order of magnitude increase of scattering and absorbing aerosols. The change was foreshadowed with small events over a 1 month period prior to the abrupt arrival of pollution over a period of a few days as air from India and Southeast Asia arrived in the Maldives at the surface level. The new, polluted aerosol was characteristically darker since the black carbon concentration increased more substantially than the overall aerosol scattering. As a result, the aerosol coalbedo at a wavelength of 550 nm showed an increase from an average of 0.028 to 0.07. Black carbon mass concentrations increased by an order of magnitude from 0.03 to 0.47 g/m3. These measurements suggest a large increase in the aerosol radiative forcing of the region with the arrival of the dry monsoon.

Deng, X. J., Coauthors, 2008: Effects of Southeast Asia biomass burning on aerosols and ozone concentrations over the Pearl River Delta (PRD) region.Atmos. Environ.,42(36),8439-8501,https://doi.org/10.1016/j.atmosenv.2008.08.013.

10.1021/jo9703459

9d96dc0d34ccfe99b09c6393d0b7d0d7

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231008007048

http://www.sciencedirect.com/science/article/pii/S1352231008007048Recent studies show that the rapid increases in urbanization and human activities in the PRD region have important impacts on regional air quality. In addition to local anthropogenic emissions which are major driving forces for poor air quality in this region, biomass burning in Southeast Asia has also important contribution on aerosol and ozone concentrations in the PRD region. In this paper, this effect is analyzed by using satellite data, ground measurements and models. MODIS aerosol optical depth (AOD) distribution in March 2006 shows a clear enhancement in AOD between Southeast Asia and the PRD region. With detail wind analysis, two distinguished conditions are classified, i.e., Condition-1 (PRD is under influence of the biomass burning from Southeast Asia) and Condition-2 (PRD is not under influence of the biomass burning from Southeast Asia). The characterizations of aerosol, UV, and ozone in Guangzhou city (located in the PRD region) under these two conditions are analyzed. The analyses suggest that aerosols and CO concentrations are higher in Condition-1 than in Condition-2; while the UV intensity and O3 concentrations are lower in Condition-1 than in Condition-2. This result indicates that in Condition-1, the enhanced aerosol concentrations from the Southeast Asia biomass burning produce reduction of UV intensity, and thus decreases the formation of ozone in Guangzhou.

Deng, X. J., Coauthors, 2011: Effect of atmospheric aerosol on surface ozone variation over the Pearl River Delta region.Science China Earth Sciences54,744-752,https://doi.org/10.1007/s11430-011-4172-7.

10.1007/s11430-011-4172-7

2ebbaa7e4ba85107235ae036003475d3

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs11430-011-4172-7

http://link.springer.com/article/10.1007/s11430-011-4172-7Our analysis of the surface aerosol and ultraviolet (UV) measurements in Pearl River Delta (PRD) region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has important impacts on urban ecosystem and photochemistry, especially on ozone photochemical production over the region. The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations (including ozone, ultraviolet radiation, aerosol radiative parameters) and by using radiative and chemical models. A case study shows that the aerosol concentrations and UV radiation are significantly correlated with ozone concentrations. The correlation coefficient between the aerosol optical depth (AOD) and the PM 10 mass concentration is very high, with a maximum of 0.98, and the AOD and UV radiation/ozone is anticorrelated, with a correlation coefficient of 0.90. The analysis suggests that ozone productivity is significantly decreased due to the reduction of UV radiation. The noon-time ozone maximum is considerably depressed when AOD is 0.6, and is further decreased when AOD is up to 1.2 due to the reduction of ozone photochemical productivity. Because the occurring probability of aerosol optical depth for AOD 550 nm 猢0.6 and AOD 340 nm 猢1.0 is 47, and 55% respectively during the dry season (October, November, December, January), this heavy aerosol condition explains the low ozone maximum that often occurs in the dry season over the Guangzhou region. The analysis also suggests that the value of single scattering albedo (SSA) is very sensitive to the aerosol radiative effect when the radiative and chemical models are applied, implying that the value of SSA needs to be carefully studied when the models are used in calculating ozone production.

Eck T. F., B. N. Holben, J. S. Reid, O. Dubovik, A. Smirnov, N. T. O'Neill, I. Slutsker, and S. Kinne, 1999: Wavelength dependence of the optical depth of biomass burning,urban, and desert dust aerosols.J. Geophys. Res.,104,31 333-31 349,https://doi.org/10.1029/1999JD900923.

10.1029/1999JD900923

6910553ba0a45a599b4bdb87a76c71df

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F1999JD900923%2Ffull

http://doi.wiley.com/10.1029/1999JD900923The Angstrom wavelength exponent , which is the slope of the logarithm of aerosol optical depth (0304a) versus the logarithm of wavelength (0203), is commonly used to characterize the wavelength dependence of 0304a and to provide some basic information on the aerosol size distribution. This parameter is frequently computed from the spectral measurements of both ground-based sunphotometers and from satellite and aircraft remote sensing retrievals. However, spectral variation of is typically not considered in the analysis and comparison of values from different techniques. We analyze the spectral measurements of 0304a from 340 to 1020 nm obtained from ground-based Aerosol Robotic Network radiometers located in various locations where either biomass burning, urban, or desert dust aerosols are prevalent. Aerosol size distribution retrievals obtained from combined solar extinction and sky radiance measurements are also utilized in the analysis. These data show that there is significant curvature in the ln 0304a versus ln 0203 relationship for aerosol size distributions dominated by accumulation mode aerosols (biomass burning and urban). Mie theory calculations of for biomass burning smoke (for a case of aged smoke at high optical depth) agree well with observations, confirming that large spectral variations in are due to the dominance of accumulation mode aerosols. A second order polynomial fit to the ln 0304a versus ln 0203 data provides excellent agreement with differences in 0304a of the order of the uncertainty in the measurements (0908040.01-0.02). The significant curvature in ln 0304a versus ln 0203 for high optical depth accumulation mode dominated aerosols results in values differing by a factor of 30900095 from 340 to 870 nm. We characterize the curvature in ln 0304a versus ln 0203 by the second derivative 090005 and suggest that this parameter be utilized in conjunction with to characterize the spectral dependence of 0304a. The second derivative of ln 0304a versus ln 0203 gives an indication of the relative influence of accumulation mode versus coarse mode particles on optical properties.

Eck, T. F., Coauthors, 2005: Columnar aerosol optical properties at AERONET sites in central eastern Asia and aerosol transport to the tropical mid-Pacific.J. Geophys. Res.,110,D06202,https://doi.org/10.1029/2004JD005274.10.1029/2004JD005274

9ebbee440b80417d0f70c0d17e725738

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2004JD005274%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2004JD005274/pdfThe column-integrated optical properties of aerosol in the central eastern region of Asia and midtropical Pacific were investigated based on Sun/sky radiometer measurements made at Aerosol Robotic Network (AERONET) sites in these regions. Characterization of aerosol properties in the Asian region is important due to the rapid growth of both population and economic activity, with associated increases in fossil fuel combustion, and the possible regional and global climatic impacts of related aerosol emissions. Multiyear monitoring over the complete annual cycle at sites in China, Mongolia, South Korea, and Japan suggest spring and/or summer maximum in aerosol optical depth (τ) and a winter minimum; however, more monitoring is needed to establish accurate climatologies. The annual cycle of Angstrom wavelength exponent (α) showed a springtime minimum associated with dust storm activity; however, the monthly mean αwas >0.8 even for the peak dust season at eastern Asian sites suggesting that fine mode pollution aerosol emitted from population centers in eastern Asia dominates the monthly aerosol optical influence even in spring as pollution aerosol mixes with coarse mode dust originating in western source regions. Aerosol optical depth peaks in spring in the tropical mid-Pacific Ocean associated with seasonal shifts in atmospheric transport from Asia, and 0035% of the springtime τenhancement occurs at altitudes above 3.4 km. For predominately fine mode aerosol pollution cases, the average midvisible (00550 nm) single scattering albedo (ω) at two continental urban sites in China averaged 000.89, while it was significantly higher, 000.93, at two relatively rural coastal sites in South Korea and Japan. Differences in fine mode absorption between these regions may result from a combination of factors including aerosol aging during transport, relative humidity differences, sea salt at coastal sites, and fuel type and combustion differences in the two regions. For cases where τwas predominately coarse mode dust aerosol in the spring of 2001, the absorption was greater in eastern Asia compared to the source regions, with ωat Dunhuang, China (near to the major Taklamakan dust source), 000.04 higher than at Beijing at all wavelengths, and Anmyon, South Korea, showing an intermediate level of absorption. Possible reasons for differences in dust absorption magnitude include interactions between dust and fine mode pollution aerosol and also variability of dust optical properties from different source regions in China and Mongolia.

Fu, X. X., Coauthors, 2014: Trends of ambient fine particles and major chemical components in the Pearl River Delta region: Observation at a regional background site in fall and winter.Science of the Total Environment497-498,274-281,https://doi.org/10.1016/j.scitotenv.2014.08.008..08. 008.10.1016/j.scitotenv.2014.08.008

25129163

cc3b9289c3811e792a30eb784cd01387

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0048969714011735

http://linkinghub.elsevier.com/retrieve/pii/S0048969714011735Abstract In the fall and winter of 2007 to 2011, 167 24-h quartz filter-based fine particle (PM2.5) samples were collected at a regional background site in the central Pearl River Delta. The PM2.5 showed an annual reduction trend with a rate of 8.58 μg m(-3) (p<0.01). The OC component of the PM2.5 reduced by 1.10 μg m(-3) yr(-1) (p<0.01), while the reduction rates of sulfur dioxide (SO2) and sulfate (SO4(2-)) were 10.2 μg m(-3) yr(-1) (p<0.01) and 1.72 μg m(-3) yr(-1) (p<0.01), respectively. In contrast, nitrogen oxides (NOx) and nitrate (NO(3-)) presented growth trends with rates of 6.73 μg m(-3) yr(-1) (p<0.05) and 0.79 μg m(-3) yr(-1) (p<0.05), respectively. The PM2.5 reduction was mainly related to the decrease of primary OC and SO4(2-), and the enhanced conversion efficiency of SO2 to SO4(2-) was related to an increase in the atmospheric oxidizing capacity and a decrease in aerosol acidity. The discrepancy between the annual trends of NOx and NO3(-) was attributable to the small proportion of NO3(-) in the total nitrogen budget. CAPSULE ABSTRACT: Understanding annual variations of PM2.5 and its chemical composition is crucial in enabling policymakers to formulate and implement control strategies on particulate pollution. Copyright 08 2014 Elsevier B.V. All rights reserved.

Ge J. M., J. Su, T. P. Ackerman, Q. Fu, J. P. Huang, and J. S. Shi, 2010: Dust aerosol optical properties retrieval and radiative forcing over northwestern China during the 2008 China-U.S. joint field experiment. J. Geophys. Res.,115,D00K12,https://doi.org/10.1029/2009JD013263.

Gobbi G. P., Y. J. Kaufman, I. Koren, and T. F. Eck, 2007: Classification of aerosol properties derived from AERONET direct sun data.Atmospheric Chemistry and Physics7,453-458,https://doi.org/10.5194/acp-7-453-2007.10.5194/acpd-6-8713-2006

a8c610ef316e71ce1c8f7ac3fc4ba317

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F2700279

http://www.atmos-chem-phys.net/7/453/2007/Aerosol spectral measurements by sunphotometers can be characterized by three independent pieces of information: 1) the optical thickness (AOT), a measure of the column aerosol concentration, 2) the optical thickness average spectral dependence, given by the Angstrom exponent (), and 3) the spectral curvature of alpha; (delta;alpha;). We propose a simple graphical method to visually convert (alpha;, delta;alpha;) to the contribution of fine aerosol to the AOT and the size of the fine aerosols. This information can be used to track mixtures of pollution aerosol with dust, to distinguish aerosol growth from cloud contamination and to observe aerosol humidification. The graphical method is applied to the analysis of yearly records at 8 sites in 3 continents, characterized by different levels of pollution, biomass burning and mineral dust concentrations. Results depict the dominance of fine mode aerosols in driving the AOT at polluted sites. In stable meteorological conditions, we see an increase in the size of the fine aerosol as the pollution stagnates and increases in optical thickness. Coexistence of coarse and fine particles is evidenced at the polluted sites downwind of arid regions.

Guo, J. P., Coauthors, 2016: Delaying precipitation and lightning by air pollution over the Pearl River Delta Part I: Observational analyses.J.Geophys.Res.,121,6472-6488,https://doi.org/10.1002/2015JD023257.10.1002/2015JD023257

cd005bbec79edd7b6cfe16602e11b4bf

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2F2015JD023257%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1002/2015JD023257/pdfThe radiative and microphysical effects of aerosols can affect the development of convective clouds. The objective of this study is to reveal if the overall aerosol effects have any discernible impact on the diurnal variations in precipitation and lightning by means of both observational analysis and modeling. As the first part of two companion studies, this paper is concerned with analyzing hourly PM, precipitation, and lightning data collected during the summers of 2008-2012 in the Pearl River Delta region. Daily PMdata were categorized as clean, medium, or polluted so that any differences in the diurnal variations in precipitation and lightning could be examined. Heavy precipitation and lightning were found to occur more frequently later in the day under polluted conditions than under clean conditions. Analyses of the diurnal variations in several meteorological factors such as air temperature, vertical velocity, and wind speed were also performed. They suggest that the influence of aerosol radiative and microphysical effects serve to suppress and enhance convective activities, respectively. Under heavy pollution conditions, the reduction in solar radiation reaching the surface delays the occurrence of strong convection and postpones heavy precipitation to late in the day when the aerosol invigoration effect more likely comes into play. Although the effect of aerosol particles can be discernible on the heavy precipitation through the daytime, the influence of concurrent atmospheric dynamics and thermodynamics cannot be ruled out.

Halthore, R. N., Coauthors, 2005: Intercomparison of shortwave radiative transfer codes and measurements.J. Geophys. Res.,110,D11206,https://doi.org/10.1029/2004JD005293.10.1029/2004JD005293

d8680984b46ed9e0cb28741dc196657d

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2004JD005293%2Ffull

http://doi.wiley.com/10.1029/2004JD005293[1] Computation of components of shortwave (SW) or solar irradiance in the surface-atmospheric system forms the basis of intercomparison between 16 radiative transfer models of varying spectral resolution ranging from line-by-line models to broadband and general circulation models. In order of increasing complexity the components are: direct solar irradiance at the surface, diffuse irradiance at the surface, diffuse upward flux at the surface, and diffuse upward flux at the top of the atmosphere. These components allow computation of the atmospheric absorptance. Four cases are considered from pure molecular atmospheres to atmospheres with aerosols and atmosphere with a simple uniform cloud. The molecular and aerosol cases allow comparison of aerosol forcing calculation among models. A cloud-free case with measured atmospheric and aerosol properties and measured shortwave radiation components provides an absolute basis for evaluating the models. For the aerosol-free and cloud-free dry atmospheres, models agree to within 1 % (root mean square deviation as a percentage of mean) in broadband direct solar irradiance at surface; the agreement is relatively poor at 5% for a humid atmosphere. A comparison of atmospheric absorptance, computed from components of SW radiation, shows that agreement among models is understandably much worse at 3% and 10% for dry and humid atmospheres, respectively. Inclusion of aerosols generally makes the agreement among models worse than when no aerosols are present, with some exceptions. Modeled diffuse surface irradiance is higher than measurements for all models for the same model inputs. Inclusion of an optically thick low-cloud in a tropical atmosphere, a stringent test for multiple scattering calculations, produces, in general, better agreement among models for a low solar zenith angle (SZA = 30℃) than for a high SZA (75℃). All models show about a 30% increase in broadband absorptance for 30℃ SZA relative to the clear-sky case and almost no enhancement in absorptance for a higher SZA of 75℃, possibly due to water vapor line saturation in the atmosphere above the cloud.

Holben, B. N., Coauthors, 1998: AERONET-A federated instrument network and data archive for aerosol characterization.Remote Sensing of Environment66,1-16,https://doi.org/10.1016/S0034-4257(98)00031-5

10.1016/S0034-4257(98)00031-5

98803f79ae78aca6042724f876bbb469

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0034425798000315

http://linkinghub.elsevier.com/retrieve/pii/S0034425798000315The concept and description of a remote sensing aerosol monitoring network initiated by NASA, developed to support NASA, CNES, and NASDA’s Earth satellite systems under the name AERONET and expanded by national and international collaboration, is described. Recent development of weather-resistant automatic sun and sky scanning spectral radiometers enable frequent measurements of atmospheric aerosol optical properties and precipitable water at remote sites. Transmission of automatic measurements via the geostationary satellites GOES and METEOSATS’ Data Collection Systems allows reception and processing in near real-time from approximately 75% of the Earth’s surface and with the expected addition of GMS, the coverage will increase to 90% in 1998. NASA developed a UNIX-based near real-time processing, display and analysis system providing internet access to the emerging global database. Information on the system is available on the project homepage, http://spamer.gsfc.nasa.gov . The philosophy of an open access database, centralized processing and a user-friendly graphical interface has contributed to the growth of international cooperation for ground-based aerosol monitoring and imposes a standardization for these measurements. The system’s automatic data acquisition, transmission, and processing facilitates aerosol characterization on local, regional, and global scales with applications to transport and radiation budget studies, radiative transfer-modeling and validation of satellite aerosol retrievals. This article discusses the operation and philosophy of the monitoring system, the precision and accuracy of the measuring radiometers, a brief description of the processing system, and access to the database.

Hu W., M. Hu, Q. Tang, S. Guo, and C. Q. Yan, 2013: Characterization of particulate pollution during Asian Games in Pearl River Delta (PRD) region. Acta Scientiae Circumstantiae, 33( 8), 1815- 1823. (in Chinese)8b546bc0133cacf68b3f9c63f1d731ee

http%3A%2F%2Fen.cnki.com.cn%2FArticle_en%2FCJFDTOTAL-HJXX201307004.htm

http://en.cnki.com.cn/Article_en/CJFDTOTAL-HJXX201307004.htmThe characteristics of particulate pollution in Pearl River Delta (PRD) region was investigated during the 2010 Asian Games in Guangzhou. Twenty-four-hour particle samples were collected simultaneously in urban site, Guangzhou, and its downwind rural site, Heshan during November 11 to 30, 2010. The major chemical components in PM2.5 including organic and elemental carbon (OC and EC) and inorganic water-soluble ions were measured. The average PM2.5 mass concentrations in Guangzhou and Heshan were (73.3±16.5) μg · m-3 and (98.2±20.8) μg · m-3, respectively. PM10 was also measured in Heshan with average concentration as 131.6 μg · m-3 and the ratio of PM2.5 to PM10 was 74%, indicating that PM2.5 pollution was a serious regional issue. As the major chemical components of PM2.5, secondary inorganic ions (SNA), organic matter (OM) and EC accounted for 39%, 31% and 5% in Guangzhou, and 42%, 26% and 6% in Heshan, respectively. Based on EC tracer method the levels of POC and SOC were estimated as 15% and 4% in Guangzhou, and 13% and 3% in Heshan. In general, secondary aerosol (SNA+SOA) contributed around 50% in PM2.5 both in Guangzhou and Heshan, suggesting that the PM2.5 in PRD region was dominated by secondary formation. Compared to Heshan and results from previous study of PRIDE-PRD2004 campaign under similar meteorology conditions, the lower concentrations of PM2.5, SNA, Cl- and EC in Guangzhou suggested that the primary emissions control was effective. PM2.5 and EC concentrations decreased significantly by 29.6 μg · m-3 (29%) and 3.5 μg · m-3 (49%), respectively.

IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change,T.F. Stocker et al.,Eds.,Cambridge University Press,Cambridge,UnitedKingdomandNewYork,NY,USA,1535pp,https://doi.org/10.1017/CBO9781107415324.

Khatri P., T. Takamura, A. Shimizu, and N. Sugimoto, 2014: Observation of low single scattering albedo of aerosols in the downwind of the East Asian desert and urban areas during the inflow of dust aerosols.J. Geophys. Res.,119,787-802,https://doi.org/10.1002/2013JD019961.10.1002/2013JB010290

d4ff2f377d6875affc8091eab58e2367

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2F2013JB010290%2Ffull

http://doi.wiley.com/10.1002/2013JB010290Acoustic velocities were measured during triaxial deformation tests of silty clay and clayey silt core samples from the Nankai subduction zone (Integrated Ocean Drilling Program Expeditions 315, 316, and 333). We provide a new data set, continuously measured during pressure increase and subsequent axial deformation. A new data processing method was developed using seismic time series analysis. Compressional wave velocities (Vp) range between about 1450 and 2200 m/s, and shear wave velocities (Vs) range between about 150 and 800 m/s. Vp slightly increases with rising effective confining pressure and effective axial stress. Samples from the accretionary prism toe show the highest Vp, while fore-arc slope sediments show lower Vp. Samples from the incoming plate, slightly richer in clay minerals, have the lowest values for Vp. Vs increases with higher effective confining pressures and effective axial stress, irrespective of composition and tectonic setting. Shear and bulk moduli are between 0.2 and 1.3 GPa, and 3.85 and 8.41 GPa, respectively. Elastic moduli of samples from the accretionary prism toe and the footwall of the megasplay fault (1.50 and 3.98 GPa) are higher than those from the hanging wall and incoming plate (0.59 and 0.88 GPa). This allows differentiation between normal and overconsolidated sediments. The data show that in a tectonosedimentary environment of only subtle compositional differences, acoustic properties can be used to differentiate between stronger (accretionary prism toe) and weaker (fore-arc slope, incoming plate) sediments. Especially Vp/Vs ratios may be instrumental in detecting zones of low effective stress and thus high pore fluid pressure.

Kim D.-H., B.-J. Sohn, T. Nakajima, and T. Takamura, 2005: Aerosol radiative forcing over East Asia determined from ground-based solar radiation measurements.J. Geophys. Res.,110,D10S22,https://doi.org/10.1029/2004JD004678.10.1029/2004JD004678

9240729cc4e3cb1af9d1ba96ed5211ee

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2004JD004678%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2004JD004678/pdf[1] We developed a method of retrieving aerosol optical properties and their associated radiative forcing from simultaneously measured sky radiation and surface solar flux data. The method is then applied to data sets collected at Mandalgovi, Dunhuang, Yinchuan, and Sri-Samrong sites of the Skyradiometer Network (SKYNET), and at Anmyon, Gosan, and Amami-Oshima, to examine the aerosol characteristics of east Asia. From the analysis for the SKYNET sites it was found that aerosols in east Asia have smaller single scattering albedos (i.e., 0.89 for Asian dusts in Dunhuang, 0.9 for urban type aerosols in Yinchuan, and 0.88 for biomass burning aerosols in Sri-Samrong), compared to the single scattering albedo for the same type of aerosols found in other areas. Lower single scattering albedo suggests that the aerosols over east Asia absorb comparatively more solar radiation. The measurements taken during April at the latter three sites over the Korean peninsula and the East China Sea showed that the single scattering albedo of Asian dust becomes smaller during the course of its movement from the source region to east Asian seawaters (i.e., 0.86 at Anmyon, 0.84 at Gosan, and 0.80 in Amami-Oshima), compared with 0.89 found in the source region (i.e., Dunhuang). These findings strongly suggest that Asian dusts become blackened during the movement because of mixing with soot particles produced over the industrial/urban area of China. The overall atmospheric forcing efficiency (radiation flux per unit aerosol optical thickness at 0.5 m) of Asian dusts ranges from 65 to 94 W m2 near the east Asian seaboard area, indicating that atmospheric heating by Asian dusts can be significantly enhanced by the mixing with soot particles.

Koren I., Y. J. Kaufman, L. A. Remer, and J. V. Martins, 2004: Measurement of the effect of Amazon smoke on inhibition of cloud formation.Science303(5662),1342-1345,https://doi.org/10.1126/science.1089424.10.1126/science.1089424

0e0c4f30d0c162ed37ac1966a0d4d67d

http%3A%2F%2Fwww.jstor.org%2Fstable%2F10.2307%2F3836396%3FSearch%3Dyes%26amp%3BresultItemClick%3Dtrue%26amp%3BsearchText%3Dau%3A%26amp%3BsearchText%3D%22Yoram%2520J.%2520Kaufman%22%26amp%3BsearchUri%3D%252Faction%252FdoBasicSearch%253Fymod%253DYour%252Binbound%252Blink%252Bdid%252Bnot%252Bhave%252Ban%252Bexact%252Bmatch%252Bin%252Bour%252Bdatabase.%252BBut%252Bbased%252Bon%252Bthe%252Belements%252Bwe%252Bcould%252Bmatch%25252C%252Bwe%252Bhave%252Breturned%252Bthe%252Bfollowing%252Bresults.%2526amp%253BQuery%253Dau%253A%252522Yoram%252BJ.%252BKaufman%252522%2526amp%253Bsi%253D1

http://www.sciencemag.org/cgi/doi/10.1126/science.1089424

Kosmopoulos P. G., D. G. Kaskaoutis, P. T. Nastos, and H. D. Kambezidis, 2008: Seasonal variation of columnar aerosol optical properties over Athens,Greece, based on MODIS data.Remote Sensing of Environment,112,2354-2366,https://doi.org/10.1016/j.rse.2007.2007.11.006.

10.1016/j.rse.2007.11.006

b140baf5ff43dfada28e36fdc3aa06fc

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0034425707004671

http://linkinghub.elsevier.com/retrieve/pii/S0034425707004671A long-term (20002005) data set of aerosol optical properties obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) is analyzed focusing on the Greater Athens Area in the Eastern Mediterranean region. The MODIS aerosol optical depth standard product (AOD at 550nm) and its respective ratio attributed to fine-mode particles (FM) are employed to evaluate the inter-annual and seasonal variability of the aerosol properties over Athens. Based on AOD 550 and FM values three specific aerosol types are discriminated corresponding to different aerosol load and optical properties. The aerosol types considered correspond to urban/industrial aerosols, coarse-mode particles and clean maritime conditions. This study focuses on the seasonal and year-to-year fluctuation of the number of occurrences as well as the AOD 550 and FM values of each aerosol type. The coarse-mode particles are observed mainly in the summer, while spring is the most favorable season for the occurrence of urban/industrial aerosols. On the other hand, clean maritime conditions occur mainly in the winter. The AOD 550 values for the coarse-mode particles are higher in spring, while the urban/industrial and clean maritime aerosols exhibit slightly higher values in the summer. The seasonal distribution of the aerosol properties is related to anthropogenic and dust emissions in the spring/summer period, but is modified by atmospheric dispersion and precipitation in late autumn/winter. The main conclusion of the study is that the coarse-mode particles exhibit much stronger inter-annual and seasonal variability compared to the urban/industrial aerosols. Finally, three cases corresponding to each aerosol type are analyzed with the aid of synoptic weather maps, air mass trajectories and MODIS data.

Lai S.-C., S.-C. Zou, J.-J. Cao, S.-C. Lee, and K.-F. Ho, 2007: Characterizing ionic species in PM_2.5 and PM₁₀ in four Pearl River Delta cities, South China. Journal of Environmental Sciences, 19, 939-947, https://doi.org/10.1016/S1001-0742(07)60155-7..

Lee C. S. L., X.-D. Li, G. Zhang, J. Li, A.-J. Ding, and T. Wang, 2007: Heavy metals and Pb isotopic composition of aerosols in urban and suburban areas of Hong Kong and Guangzhou,South China-Evidence of the long-range transport of air contaminants.Atmos. Environ.,41(3),432-447,https://doi.org/10.1016/j.atmosenv.2006.07.035.

10.1007/BF02839976

079a7d490daf0ad6b0fb181820c84463

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231006008223

http://linkinghub.elsevier.com/retrieve/pii/S1352231006008223Rapid urbanization and industrialization in South China has placed great strain on the environment and on human health. In the present study, the total suspended particulate matter (TSP) in the urban and suburban areas of Hong Kong and Guangzhou, the two largest urban centres in South China, was sampled from December 2003 to January 2005. The samples were analysed for the concentrations of major elements (Al, Fe, Mg and Mn) and trace metals (Cd, Cr, Cu, Pb, V and Zn), and for Pb isotopic composition. Elevated concentrations of metals, especially Cd, Pb, V and Zn, were observed in the urban and suburban areas of Guangzhou, showing significant atmospheric trace element pollution. Distinct seasonal patterns were observed in the heavy metal concentrations of aerosols in Hong Kong, with higher metal concentrations during the winter monsoon period, and lower concentrations during summertime. The seasonal variations in the metal concentrations of the aerosols in Guangzhou were less distinct, suggesting the dominance of local sources of pollution around the city. The Pb isotopic composition in the aerosols of Hong Kong had higher 206 Pb/ 207 Pb and 208 Pb/ 207 Pb ratios in winter, showing the influence of Pb from the northern inland areas of China and the Pearl River Delta (PRD) region, and lower 206 Pb/ 207 Pb and 208 Pb/ 207 Pb ratios in summer, indicating the influence of Pb from the South Asian region and from marine sources. The back trajectory analysis showed that the enrichment of heavy metals in Hong Kong and Guangzhou was closely associated with the air mass from the north and northeast that originated from northern China, reflecting the long-range transport of heavy metal contaminants from the northern inland areas of China to the South China coast.

Li, Z. Q., Coauthors, 2007: Aerosol optical properties and their radiative effects in northern China.J. Geophys. Res.,112,D22S01,https://doi.org/10.1029/2006JD007382.10.1029/2006JD007382

7135847667eb150980a24e83329aed35

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD007382%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2006JD007382/pdfABSTRACT As a fast developing country covering a large territory, China is experiencing rapid environmental changes. High concentrations of aerosols with diverse properties are emitted in the region, providing a unique opportunity for understanding the impact of environmental changes on climate. Until very recently, few observational studies were conducted in the source regions. The East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE) attempts to characterize the physical, optical and chemical properties of the aerosols and their effects on climate over China. This study presents some preliminary results using continuous high-quality measurements of aerosol, cloud and radiative quantities made at the first EAST-AIRE baseline station at Xianghe, about 70 km east of Beijing over a period of one year (September 2004 to September 2005). It was found that the region is often covered by a thick layer of haze (with a yearly mean aerosol optical depth equal to 0.82 at 500 nm and maximum greater than 4) due primarily to anthropogenic emissions. An abrupt “cleanup” of the haze often took place in a matter of one day or less because of the passage of cold fronts. The mean single scattering albedo is approximately 0.9 but has strong day-to-day variations with maximum monthly averages occurring during the summer. Large aerosol loading and strong absorption lead to a very large aerosol radiative effect at the surface (the annual 24-hour mean values equals 24 W m612), but a much smaller aerosol radiative effect at the top of the atmosphere (one tenth of the surface value). The boundary atmosphere is thus heated dramatically during the daytime, which may affect atmospheric stability and cloud formation. In comparison, the cloud radiative effect at the surface is only moderately higher (6141 W m612) than the aerosol radiative effect at the surface.

Li Z. Q., K.-H. Lee, Y. S. Wang, J. Y. Xin, and W.-M. Hao, 2010: First observation-based estimates of cloud-free aerosol radiative forcing across China.J. Geophys. Res.,115,D00K18,https://doi.org/10.1029/2009JD013306.10.1029/2009JD013306

0050ed21b22ad42c6cd6fe7352832649

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2009JD013306%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2009JD013306/fullHeavy loading of aerosols in China is widely known, but little is known about their impact on regional radiation budgets, which is often expressed as aerosol radiative forcing (ARF). Cloud-free direct ARF has either been estimated by models across the region or determined at a handful of locations with aerosol and/or radiation measurements. In this study, ARF is determined at 25 stations distributed across China where aerosol optical thickness has been measured since 2004. In combination with the single-scattering albedo retrieved from ground and satellite measurements, ARF was determined at all the stations at the surface, inside the atmosphere, and at the top of atmosphere (TOA). Nationwide annual and diurnal mean ARF is found to be -15.7 8.9 at the surface, 0.3 1.6 at the TOA, and 16.0 9.2 W minside the atmosphere. These values imply that aerosols have very little impact on the atmosphere-surface system but substantially warm up the atmosphere at the expense of cooling the surface. The strong atmospheric absorption is likely to alter atmospheric thermodynamic conditions and thus affects circulation considerably.

Li, Z. Q., Coauthors, 2016: Aerosol and monsoon climate interactions over Asia.Rev. Geophys.,54(5),866-929,https://doi.org/10.1002/2015RG000500.10.1002/2015RG000500

58ffc99783679393c533eed616bddb17

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2F2015RG000500%2Fpdf

http://doi.wiley.com/10.1002/2015RG000500The increasing severity of droughts/floods and worsening air quality from increasing aerosols in Asia monsoon regions are the two gravest threats facing over 60% of the world population living in Asian monsoon regions. These dual threats have fueled a large body of research in the last decade on the roles of aerosols in impacting Asian monsoon weather and climate. This paper provides a comprehensive review of studies on Asian aerosols, monsoons, and their interactions. The Asian monsoon region is a primary source of emissions of diverse species of aerosols from both anthropogenic and natural origins. The distributions of aerosol loading are strongly influenced by distinct weather and climatic regimes, which are, in turn, modulated by aerosol effects. On a continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulations. The atmospheric thermodynamic state, which determines the formation of clouds, convection, and precipitation, may also be altered by aerosols serving as cloud condensation nuclei or ice nuclei. Absorbing aerosols such as black carbon and desert dust in Asian monsoon regions may also induce dynamical feedback processes, leading to a strengthening of the early monsoon and affecting the subsequent evolution of the monsoon. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of different monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from biomass burning, and biogenic aerosols from vegetation are considered integral components of an intrinsic aerosol-monsoon climate system, subject to external forcing of global warming, anthropogenic aerosols, and land use and change. Future research on aerosol-monsoon interactions calls for an integrated approach and international collaborations based on long-term sustained observations, process measurements, and improved models, as well as using observations to constrain model simulations and projections.

Liang S. L., 2001: Narrowband to broadband conversions of land surface albedo.I: Algorithms. Remote Sensing of Environment76,213-238,https://doi.org/10.1016/S0034-4257(00)00205-4.

10.1016/S0034-4257(00)00205-4

19a08f96773e90c491c7d519b08f1bd5

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0034425700002054

http://linkinghub.elsevier.com/retrieve/pii/S0034425700002054Land surface broadband albedo is a critical variable for many scientific applications. High-resolution narrowband satellite observations contain important information that enables us to map land surface albedo globally, and validate the coarse-resolution albedo products from the broadband sensors using ground 減oint/plot measurements. However, the conversions from narrowband to broadband albedos of a general surface type have not been well established. Most studies compute total shortwave albedo based on either the empirical relations between surface total shortwave albedo measurements and satellite observations or radiative transfer simulations with the limited number of surface reflectance spectra because of the computational constraints. As a result, many conversion formulae for the same sensors are quite different. In this study, we applied an approach that decouples surface reflectance spectra from the real-time radiative transfer simulations so that many different surface reflectance spectra and the atmospheric conditions can be effectively incorporated. The conversion formulae, based on extensive radiative transfer simulations, are provided in this paper for calculating the total shortwave albedo, total-, direct-, and diffuse-visible, and near-infrared broadband albedos for several narrowband sensors, including ASTER, AVHRR, ETM+/TM, GOES, MODIS, MISR, POLDER, and VEGETATION. Some of these formulae were compared with the published formulae of the same sensors and further validations using extensive ground measurements will be discussed in the companion paper.

Liu J., X. Xia, P. Wang, Z. Li, Y. Zheng, M. Cribb, and H. Chen, 2007: Significant aerosol direct radiative effects during a pollution episode in northern China.Geophys. Res. Lett.,34,L23808,https://doi.org/10.1029/2007GL030953.10.1029/2007GL030953

43fa48d720a8ab2e92ff0e093cf4027b

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2007GL030953%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2007GL030953/fullDirect aerosol radiative effects during a heavy pollution episode that occurred in October 2004 over northern China are explored on the basis of ground-based and satellite-retrieved data. Aerosol loading rapidly built up due to a strong inversion and high relative humidity, with aerosol optical depth (AOD) at 550 nm increasing steadily from about 0.1 on October 1 to more than 1.0 six days later. Reflected irradiances at the top of the atmosphere (TOA) and surface irradiances change dramatically in response to the variation of the AOD. At the peak of the heavy pollution episode, the instantaneous reflected irradiances at the TOA increased by about 50 Wm, while the instantaneous irradiances at the surface decreased by about 350 Wm, resulting in solar heating of the atmosphere on the order of 300 Wm. Solar radiation reflected to the space increased due to the build up of aerosols, indicating an overall cooling effect of the aerosols in the region.

Liu J. J., Y. F. Zheng, Z. Q. Li, and R. J. Wu, 2008: Ground-based remote sensing of aerosol optical properties in one city in northwest China.Atmos. Res.,89,194-205,https://doi.org/10.1016/j.atmosres.2008.01.010.

10.1016/j.atmosres.2008.01.010

a1f41d19ef0fee3d14023bc4a7b48357

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0169809508000264

http://linkinghub.elsevier.com/retrieve/pii/S0169809508000264The aerosol volume size distributions can be characterized by the sum of two log-normal distributions, and represented an accumulation mode with a radius of about 0.15μm, and a coarse mode with a radius of about 7μm, which was the main aerosol mode in this area. The real parts of the refraction index rose in spring, and exhibited a low sensitivity to wavelengths; the imaginary parts of the refractive index decreased noticeably in spring and also showed a low sensitivity to wavelength. Both their low sensitivities to wavelengths slightly varied with time, but no clear patterns were found. The aerosol single scattering albedo in spring was much higher than in other seasons, and increased dramatically with increase in wavelength, from 0.92 at 400nm to 0.97 at 1020nm. In other seasons, it showed a slightly decreased with wavelength. The aerosol direct radiative forcing efficiency at the short wavelength is 610255.31, 610259.71, 610260.13 and 610260.38 at surface and 13.89, 10.39, 2.30 and 2.64 at TOA in spring, summer, autumn and winter, respectively. The value at surface/TOA in spring is lower/higher than that in other seasons, indicating the influence of the dust aerosol.

Liu J. J., Y. F. Zheng, Z. Q. Li, C. Flynn, and M. Cribb, 2012: Seasonal variations of aerosol optical properties,vertical distribution and associated radiative effects in the Yangtze Delta region of China.J. Geophys. Res.,117,D00K38,https://doi.org/10.1029/2011JD016490.

10.1029/2011JD016490

3b0eabb5e28afbef91d921c12e5314fb

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2011JD016490%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2011JD016490/pdf[1] Four years of columnar aerosol optical properties and a one-year vertical profiles of aerosol particle extinction coefficient at 527 nm are analyzed at Taihu in the central Yangtze River Delta region in eastern China. Seasonal variations of aerosol optical properties, vertical distribution, and influence on shortwave radiation and heating rates were investigated. Multiyear variations of aerosol optical depths (AOD), 0105ngstrom exponents, single scattering albedo (SSA) and asymmetry factor (ASY) are analyzed, together with the vertical profile of aerosol extinction. AOD is largest in summer and smallest in winter. SSAs exhibit weak seasonal variation with the smallest values occurring during winter and the largest during summer. The vast majority of aerosol particles are below 2 km, and about 62%, 67%, 67% and 83% are confined to below 1 km in spring, summer, autumn and winter, respectively. Five-day back trajectory analyses show that the some aerosols aloft are traced back to northern/northwestern China, as far as Mongolia and Siberia, in spring, autumn and winter. The presence of dust aerosols were identified based on the linear depolarization measurements together with other information (i.e., back trajectory, precipitation, aerosol index). Dust strongly impacts the vertical particle distribution in spring and autumn, with much smaller effects in winter. The annual mean aerosol direct shortwave radiative forcing (efficiency) at the bottom, top and within the atmosphere are 09080834.8 00± 9.1 (09080854.4 00± 5.3), 0908088.2 00± 4.8 (09080813.1 00± 1.5) and 26.7 00± 9.4 (41.3 00± 4.6) W/m2 (Wm0908082 03040908081), respectively. The mean reduction in direct and diffuse radiation reaching surface amount to 109.2 00± 49.4 and 66.8 00± 33.3 W/m2, respectively. Aerosols significantly alter the vertical profile of solar heating, with great implications for atmospheric stability and dynamics within the lower troposphere.

Liu, Y., Coauthors, 2011: Aerosol optical properties and radiative effect determined from sky-radiometer over Loess Plateau of Northwest China.Atmos. Chem. Phys.11,11 455-11 463,https://doi.org/10.5194/acp-11-11455-2011.10.5194/acp-11-11455-2011

d87e78844a727abdddf0d6127643cdd8

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F2696261

http://www.oalib.com/paper/2696261The aerosol optical properties and their associated radiative effects are derived from sky-radiometer and surface solar radiation data collected over the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) for the period of March to May (MAM) 2009. The result shows that the seasonal mean aerosol optical depth (AOD) at 500 nm in MAM is 0.40. The single scattering albedo (SSA) at 500 nm in MAM at SACOL fluctuates significantly ranging from 0.82 to 0.98. The averaged value of SSA there for background aerosol is 0.90 in MAM, while it is smaller (0.87) during the dust event outbreak period. The smaller SSA can be interpreted as the result of larger particles during dust events. The averaged asymmetry factor (ASY) at 500 nm during dust event period is 0.73, which is larger than 0.70 of background aerosols. The averaged shortwave radiative effects of the aerosols during dust event period in MAM are 0.68, 70.02 and 70.70 W m 2, respectively, at the top of the atmosphere (TOA), surface and in the atmosphere. The aerosols heat the atmosphere during dust event period by up to about 2 K day 1 (daily averaged), which is 60 % larger than the heating (1.25 K day 1) of background aerosols. The significant heating effect in the atmosphere of the aerosols during dust event is determined by larger AOD and smaller SSA.

Logan T., B. Xi, X. Dong, Z. Li, and M. Cribb, 2013: Classification and investigation of Asian aerosol absorptive properties.Atmos. Chem. Phys.13,2253-2265,https://doi.org/10.5194/acp-13-2253-2013.10.5194/acp-13-2253-2013

73be044389cc54533e5f78adfdcbc0bb

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F1366135

http://www.atmos-chem-phys.net/13/2253/2013/Asian aerosols are among the most complex yet widely studied components of the atmosphere not only due to their seasonal variability but also their effects on climate change. Four Aerosol Robotic Network (AERONET) sites have been selected to represent aerosol properties dominated by pollution (Taihu), mixed complex particle types (Xianghe), desert-urban (SACOL), and biomass (Mukdahan) in East Asia during the 2001-2010 period. The volume size distribution, aerosol optical depth (tau and tau(abs)), Angstrom exponent (alpha and alpha(abs)), and the single scattering co-albedo (omega(oabs)) parameters over the four selected sites have been used to (a) illustrate seasonal changes in aerosol size and composition and (b) discern the absorptive characteristics of black carbon (BC), organic carbon (OC), mineral dust particles, and mixtures. A strongly absorbing mineral dust influence is seen at the Xianghe, Taihu, and SACOL sites during the spring months (MAM), as given by coarse mode dominance, mean alpha(440-870) 1.5. There is a shift towards weakly absorbing pollution (sulfate) and biomass (OC) aerosol dominance in the summer (JJA) and autumn (SON) months, as given by a strong fine mode influence, alpha(440-870) > 1, and alpha(abs440-870) 1 and alpha(abs440-870) > 1.5). At Mukdahan, a strong fine mode influence is evident year round, with weakly and strongly absorbing biomass particles dominant in the autumn and winter months, respectively, while particles exhibit variable absorption during the spring season. A classification method using alpha(440-870) and omega(oabs440) is developed in order to infer the seasonal physico-chemical properties of the aerosol types, such as fine and coarse mode, weak and strong absorption, at the four selected Asian sites.

McClatchey R. A., R. W. Fenn, J. E. A. Selby, F. E. Volz, and J. S. Garing, 1972: Optical Properties of the Atmosphere.3rd ed. Air Force Cambridge Research LaboratoryBedford,MA,USA,113pp.

Mitchell R. M., B. W. Forgan, 2003: Aerosol measurement in the Australian outback: Intercomparison of sun photometers. J. Atmos. Oceanic Technol., 20, 54-66, https://doi.org/10.1175/1520-0426(2003)020<0054:AMITAO>2.0.CO;2.

10.1175/1520-0426(2003)0202.0.CO;2

ed82607e714fecb7d034ce8ce23210ab

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2003JAtOT..20...54M

http://adsabs.harvard.edu/abs/2003JAtOT..20...54MAbstract The low background aerosol loadings prevailing over much of the Australian continent necessitate careful attention to the calibration of sun photometers. The validity of such calibrations can only be assessed objectively by intercomparison of independent systems operating side by side. This paper documents two intercomparisons: the first between three dissimilar photometers collocated at Alice Springs using independent calibration methods, and the second between identical photometers sited at Tinga Tingana in the Strzelecki Desert of South Australia. The intercomparison of total optical depth derived from two Cimel CE318 systems at Tinga Tingana shows negligible biases (<0.0004) at all four wavelengths. Instantaneous differences in total optical depth are used to infer 95% uncertainty intervals, which range from 0.003 at 670 nm to 0.005 at 870 nm. The Alice Springs intercomparison shows negligible bias between the Carter揝cott SPO1A and Cimel CE318 at 500 nm, while a bias of 0.004 between the two...

Nakajima T., G. Tonna, R. Z. Rao, P. Boi, Y. J. Kaufman, and B. Holben, 1996: Use of sky brightness measurements from ground for remote sensing of particulate polydispersions.Appl. Opt.,35(15),2672-2686,https://doi.org/10.1364/AO.35.002672.

10.1364/AO.35.002672

21085415

dd70c885587cf5b729960e39653a4243

http%3A%2F%2Fwww.opticsinfobase.org%2Fao%2Fabstract.cfm%3Furi%3Dao-35-15-2672

https://www.osapublishing.org/abstract.cfm?URI=ao-35-15-2672The software code SKYEAD.pack for retrieval of aerosol size distribution and optical thickness from data of direct and diffuse solar radiation is described; measurements are carried out with sky radiometers in the wavelength range 0.369-1.048 m. The treatment of the radiative transfer problem concerning the optical quantities is mainly based on the IMS (improved multiple and single scattering) method, which uses the delta-M approximation for the truncation of the aerosol phase function and corrects the solution for the first- and second-order scattering. Both linear and nonlinear inversion methods can be used for retrieving the size distribution. Improved calibration methods for both direct and diffuse radiation, the data-analysis procedure, the results from the proposed code, and several connected problems are discussed. The results can be summarized as follows: (a) the SKYRAD.pack code can retrieve the columnar aerosol features with accuracy and efficiency in several environmental situations, provided the input parameters are correctly given; (b) when data of both direct and diffuse solar radiation are used, the detectable radius interval for aerosol particles is approximately from 0.03 to 10 m; (c) besides the retrieval of the aerosol features, the data-analysis procedure also permits the determination of average values for three input parameters (real and imaginary aerosol refractive index, ground albedo) from the optical data; (d) absolute calibrations for the sky radiometer are not needed, and calibrations for direct and diffuse radiation can be carried out with field data; (e) the nonlinear inversion gives satisfactory results in a larger radius interval, without the unrealistic humps that occur with the linear inversion, but the results strongly depend on the first-guess spectrum; (f) aerosol features retrieved from simulated data showed a better agreement with the given data for the linear inversion than for the nonlinear inversion.

Nakajima, T., Coauthors, 2003: Significance of direct and indirect radiative forcings of aerosols in the East China Sea region.J. Geophys. Res.,108(D23),8658,https://doi.org/10.1029/2002JD003261.10.1029/2002JD003261

4638e58cabb6401774d7c69343768645

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2002JD003261%2Fabstract

http://doi.wiley.com/10.1029/2002JD003261Radiative forcings of aerosols and clouds in the East China Sea region are studied using data from surface radiation measurements, satellite remote sensing, and model simulation conducted in April 2001 as a study of Asian Atmospheric Particle Environmental Change Studies (APEX) cooperating with International Global Atmospheric Chemistry (IGAC)/ACE-Asia project. The monthly mean whole sky radiative forcing of the aerosol direct effect is derived from various methods as -5 to -8 W/mat the top of atmosphere (TOA) and -10 to -23 W/mat Earth's surface of Gosan (33.28N, 127.17E) and Amami-Oshima (28.15N, 129.30E) sites, though there is a large regional difference caused by changes in the aerosol optical thickness and single scattering albedo. The cloud forcing is estimated as -20 to -40 W/m, so that the aerosol direct forcing can be comparable to the cloud radiative forcing at surface. However, the estimate of the aerosol direct forcing thus obtained strongly depends on the estimation method of the aerosol properties, especially on the single scattering albedo, generating a method difference about 40%. The radiative forcing of the aerosol indirect effect is roughly estimated from satellite method and SPRINTARS model as -1 to -3 W/mat both TOA and surface.

Pathak B., G. Kalita, K. Bhuyan, P. K. Bhuyan, and K. K. Moorthy, 2010: Aerosol temporal characteristics and its impact on shortwave radiative forcing at a location in the northeast of India.J. Geophys. Res.,115,D19204,https://doi.org/10.1029/2009JD013462.10.1029/2009JD013462

354cb4c20636f972013c9558980cb8b8

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2009JD013462%2Fpdf

http://doi.wiley.com/10.1029/2009JD013462[1] Measurements of aerosol optical depth (AOD) and mass concentration of composite and black carbon (BC) aerosols made with collocated instruments over Dibrugarh in Northeast India are used to estimate the aerosol radiative forcing for the period June 2008 to May 2009. AOD shows seasonal variation with maximum in premonsoon (0.69 00± 0.13 at 500 nm in March 2009) and minimum in the retreating monsoon (0.08 00± 0.01 at 500 nm in October 2008). 0105ngstr0109m coefficients and 0205 are highest in monsoon and premonsoon season and are lowest in premonsoon and retreating monsoon, respectively. The size segregated mass concentration is minimum in the monsoon season for all the three modes nucleation, accumulation, and coarse and maximum in winter for accumulation and coarse and in premonsoon for nucleation mode. The BC mass concentration is highest 16.3 00± 1.4 0204g m0908083 in winter and lowest 3.4 00± 0.9 0204g m0908083 in monsoon. The estimated aerosol radiative forcing of the atmosphere, using Optical Properties of Aerosols and Clouds (OPAC) outputs as inputs for Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART), is maximum in premonsoon followed by that in winter and minimum in retreating monsoon. Negative forcing is observed at the surface, whereas the top of the atmosphere (TOA) forcing is nearly zero in retreating monsoon and is negative in rest of the seasons. The forcing efficiency and heating rate were highest during winter and premonsoon, respectively.

Qin Y., R. M. Mitchell, 2009: Characterisation of episodic aerosol types over the Australian continent.Atmos. Chem. Phys.9(7),1943-1956,https://doi.org/10.5194/acp-9-1943-2009.10.5194/acp-9-1943-2009

9fea9858754a62d6c1b112e4fb972434

http%3A%2F%2Fonlinelibrary.wiley.com%2Fresolve%2Freference%2FXREF%3Fid%3D10.5194%2Facp-9-1943-2009

http://www.atmos-chem-phys.net/9/1943/2009/Classification of Australian continental aerosol types resulting from episodes of enhanced source activity, such as smoke plumes and dust outbreaks, is carried out via cluster analysis of optical properties obtained from inversion of sky radiance distributions at Australian aerosol ground stations using data obtained over the last decade. The cluster analysis distinguishes four significant classes, which are identified on the basis of their optical properties and provenance as determined by satellite imagery and back-trajectory analysis. The four classes are identified respectively as aged smoke, fresh smoke, coarse dust and a super-absorptive aerosol. While the first three classes show similarities with comparable aerosol types identified elsewhere, the super-absorptive aerosol has no obvious foreign prototype. The class identified as coarse dust shows a prominent depression in single scattering albedo in the blue spectral region due to absorption by hematite, which is shown to be more abundant in central Australian dust relative to the quot;dust beltquot;of the Northern Hemisphere. The super-absorptive class is distinctive in view of its very low single scattering albedo (~0.7 at 500 nm) and variable enhanced absorption at 440 nm. The strong absorption by this aerosol requires a high black carbon content while the enhanced blue-band absorption may derive from organic compounds emitted during the burning of specific vegetation types. This aerosol exerts a positive radiative forcing at the top of atmosphere (TOA), with a large deposition of energy in the atmosphere per unit aerosol optical depth. This contrasts to the other three classes where the TOA forcing is negative. Optical properties of the four types will be used to improve the representation of Australian continental aerosol in climate models, and to enhance the accuracy of satellite-based aerosol retrievals over Australia.

Ramanathan, V., Coauthors, 2001: Indian Ocean experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze.J. Geophys. Res.,106,28 371-28 398,https://doi.org/10.1029/2001JD900133.10.1029/2001JD900133

06f5b1c76072f9f2054574b245ea419a

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2001JD900133%2Fabstract

http://doi.wiley.com/10.1029/2001JD900133Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects. The haze particles consisted of several inorganic and carbonaceous species, including absorbing black carbon clusters, fly ash, and mineral dust. The most striking result was the large loading of aerosols over most of the South Asian region and the North Indian Ocean. The January to March 1999 visible optical depths were about 0.5 over most of the continent and reached values as large as 0.2 over the equatorial Indian ocean due to long-range transport. The aerosol layer extended as high as 3 km. Black carbon contributed about 14% to the fine particle mass and 11% to the visible optical depth. The single-scattering albedo estimated by several independent methods was consistently around 0.9 both inland and over the open ocean. Anthropogenic sources contributed as much as 80% (10%) to the aerosol loading and the optical depth. The in situ data, which clearly support the existence of the first indirect effect (increased aerosol concentration producing more cloud drops with smaller effective radii), are used to develop a composite indirect effect scheme. The Indo-Asian aerosols impact the radiative forcing through a complex set of heating (positive forcing) and cooling (negative forcing) processes. Clouds and black carbon emerge as the major players. The dominant factor, however, is the large negative forcing (-204 W m2) at the surface and the comparably large atmospheric heating. Regionally, the absorbing haze decreased the surface solar radiation by an amount comparable to 50% of the total ocean heat flux and nearly doubled the lower tropospheric solar heating. We demonstrate with a general circulation model how this additional heating significantly perturbs the tropical rainfall patterns and the hydrological cycle with implications to global climate.

Ricchiazzi P., S. R. Yang, C. Gautier, and D. Sowle, 1998: SBDART: A research and teaching software tool for plane-parallel radiative transfer in the Earth's atmosphere. Bull. Amer. Meteor. Soc., 79, 2101-2114, https://doi.org/10.1175/1520-0477(1998)079<2101:SARATS>2.0.CO;2.

10.1175/1520-0477(1998)0792.0.CO;2

dd6c9863d2a2da8f4b805de3bae4e8a3

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F1998BAMS...79.2101R

http://adsabs.harvard.edu/abs/1998BAMS...79.2101RSBDART is a software tool that computes plane-parallel radiative transfer in clear and cloudy conditions within the earth's atmosphere and at the surface. All important processes that affect the ultraviolet, visible, and infrared radiation fields are included. The code is a marriage of a sophisticated discrete ordinate radiative transfer module, low-resolution atmospheric transmission models, and Mie scattering results for light scattering by water droplets and ice crystals. The code is well suited for a wide variety of atmospheric radiative energy balance and remote sensing studies. It is designed so that it can be used for case studies as well as sensitivity analysis. For small sets of computations or teaching applications it is available on the World Wide Web with a user-friendly interface. For sensitivity studies requiring many computations it is available by anonymous FTP as a well organized and documented FORTRAN 77 source code.

Rosenfeld D., U. Lohmann, G. B. Raga, C. D. O'Dowd, M. Kulmala, S. Fuzzi, A. Reissell, and M. O. Andreae, 2008: Flood or drought: How do aerosols affect precipitation? Science,321, 1309-1313, https://doi.org/10.1126/science.1160606.10.1126/science.1160606

18772428

2e53b2c54e98295c28176b844e81c9ef

http%3A%2F%2Feuropepmc.org%2Fabstract%2Fmed%2F18772428

http://europepmc.org/abstract/med/18772428Aerosols serve as cloud condensation nuclei (CCN) and thus have a substantial effect on cloud properties and the initiation of precipitation. Large concentrations of human-made aerosols have been reported to both decrease and increase rainfall as a result of their radiative and CCN activities. At one extreme, pristine tropical clouds with low CCN concentrations rain out too quickly to mature into long-lived clouds. On the other hand, heavily polluted clouds evaporate much of their water before precipitation can occur, if they can form at all given the reduced surface heating resulting from the aerosol haze layer. We propose a conceptual model that explains this apparent dichotomy.

Smirnov A., B. N. Holben, T. F. Eck, O. Dubovik, and I. Slutsker, 2000: Cloud-screening and quality control algorithms for the AERONET database.Remote Sensing of Environment73,337-349,https://doi.org/10.1016/S0034-4257(00)00109-7.

10.1016/S0034-4257(00)00109-7

d13ffc69d13c67f18de73e3322c59676

http%3A%2F%2Fwww.cabdirect.org%2Fabstracts%2F20003002999.html

http://linkinghub.elsevier.com/retrieve/pii/S0034425700001097Automatic globally distributed networks for monitoring aerosol optical depth provide measurements of natural and anthropogenic aerosol loading, which is important in many local and regional studies as well as global change research investigations. The strength of such networks relies on imposing a standardization of measurement and processing, allowing multiyear and large-scale comparisons. The development of the Aerosol Robotic Network (AERONET) for systematic ground-based sunphotometer measurements of aerosol optical depth is an essential and evolving step in this process. The growing database requires the development of a consistent, reproducible, and system-wide cloud-screening procedure. This paper discusses the methodology and justification of the cloud-screening algorithm developed for the AERONET database. The procedure has been comprehensively tested on experimental data obtained in different geographical and optical conditions. These conditions include biomass burning events in Brazil and Zambia, hazy summer conditions in the Washington DC area, clean air advected from the Canadian Arctic, and variable cloudy conditions. For various sites our screening algorithm eliminates from 20% to 50% of the initial data depending on cloud conditions. Certain shortcomings of the proposed procedure are discussed.

Tao, R., Coauthors, 2014: Development of an integrating sphere calibration method for Cimel sunphotometers in China aerosol remote sensing network.Particuology13,88-99,https://doi.org/10.1016/j.partic.2013.04.009..10.1016/j.partic.2013.04.009

6950f9b7974dc6c90da4116606f88a83

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1674200113001491

http://linkinghub.elsevier.com/retrieve/pii/S1674200113001491Based on the integrating sphere traced from the National Institute of Standards and Technology (NIST, USA), a sphere calibration method and protocol for the China aerosol remote sensing network (CARSNET) Cimel sun photometer was established. Four CE318 sun photometers were verified using the proposed calibration method and operational protocol. The calibration results showed that the instrument coefficients differed by less than 3% for visible (655% for infrared) wavelengths from the original ones stated by Cimel Electronique. In situ validation experiment data showed that radiances at ±6° measured by sun collimator (aureole) were consistent with those measured by sky collimator (sky), under both almucantar (ALMUC) and principal plane (PPLAN) scenarios. Differences at all wavelengths were less than 1%, indicating that the method and protocol are suitable for CARSNET field sun photometer calibration, and would benefit improvement of data quality and accuracy of network observations.

Valenzuela A., F. J. Olmo, H. Lyamani, M. Antón A. Quirantes, and L. Alados-Arboledas, 2012: Classification of aerosol radiative properties during African desert dust intrusions over southeastern Spain by sector origins and cluster analysis.J. Geophys. Res.,117,D06214,https://doi.org/10.1029/2011JD016885.10.1029/2011JD016885

cb438facf3b02c86851c63fab3239bff

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2011JD016885%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2011JD016885/full[1] The main goal of this study is to analyze the dependence of columnar aerosol optical and microphysical properties on source region and transport pathways during desert dust intrusions over Granada (Spain) from January 2005 to December 2010. Columnar aerosol properties have been derived from a non-spherical inversion code using the solar extinction measurements and sky radiances in the principal plane. Two classification methods of the African air masses ending at the study location were used by means of the HYSPLIT back-trajectories analysis. The first one, based on desert dust origin sources, discriminated the optical properties only for sector B (corresponding to western Sahara, northwest Mauritania and southwest Algeria). The particles present marked absorbing properties (low value of single scattering albedo at all wavelengths) during the desert dust events when the air masses were transported from sector A (north Morocco, northwest Algeria). This result may be related to the mixing of desert dust with anthropogenic pollutants from North African industrial areas in addition to the mixing with local anthropogenic aerosol and pollutants transported from European and Mediterranean areas. The second classification method was based on a statistics technique called cluster classification which allows grouping the air masses back trajectories with similar speed and direction of the trajectory. This method showed slight differences in the optical properties between the several transport pathways of air masses. High values of the aerosol optical depth and low mean values of the Angstrm parameter were associated with longer transport pathways over desert dust sources and slowly moving air masses. Both classification methods showed that the fine mode was mixed with coarse mode, being the fine mode fraction smaller than 55%.

Wang M. X., 1999: Atmospheric Chemistry. China Meteorological Press, Beijing. (in Chinese)

Wang P., H. Z. Che, X. C. Zhang, Q. L. Song, Y. Q. Wang, Z. H. Zhang, X. Dai, and D. J. Yu, 2010: Aerosol optical properties of regional background atmosphere in Northeast China.Atmos. Environ.,44,4404-4412,https://doi.org/10.1016/j.atmosenv.2010.07.043.

10.1016/j.atmosenv.2010.07.043

d25f3604c2b2ef3bc366d0984890e1bc

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231010006230

http://linkinghub.elsevier.com/retrieve/pii/S1352231010006230Aerosol optical properties from 2005 to 2008 at the Longfengshan regional background station in Northeast China were measured and analyzed. The annual mean of aerosol optical depth (AOD) at 44002nm for the four years was about 0.2702±020.25, 0.3902±020.37, 0.3502±020.34, and 0.3802±020.38, respectively, and the corresponding annual mean for the Angstrom exponent between 44002nm and 87002nm was about 1.4302±020.48, 1.2302±020.37, 1.5302±020.47, and 1.5502±020.42. The average monthly AOD 440nm showed similar seasonal variation with a maximum in spring and a minimum in autumn. The monthly means of AOD at 440, 675, 870 and 1020 nm increase from the January to March with the maxima about 0.7702±020.04, 0.6502±020.04, 0.5802±020.06, 0.5702±020.07, respectively and decrease from September to February with the minima about 0.3202±020.12, 0.2202±020.09, 0.1502±020.08, and 0.1302±020.07 in January. The monthly mean of Angstrom exponent shows a minimum in March (0.9702±020.52) and a maximum in September (1.6602±020.29). Both the AOD and Angstrom exponent presents single peak distributions of occurrence frequencies. The Longfenshan data showed high AODs (>1.00) both clustering in the fine mode growth wing and the coarse mode. Two typical cases under dust and haze conditions showed that the AOD under dusty day decreased from 2.20 to 1.20 and the Angstrom exponent increased from 0.10 to 1.00. On the contrast, the AOD under haze day remained relatively stable about 0.90 and the Angstrom exponent was around 1.40. The 3-day backtrajectory analysis at Longfengshan illustrated that the air-masses near ground on the dust day were from Bohai Sea and passed through Liaodong Peninsula and Northeast plain in China. But the air-masses on 50002m AGL were originated from western Mongolia and crossed Gobi deserts, Otindag Sand Land and Horqin Sand Land in Northeast China. The air-masses at Longfengshan near ground 50002m and 100002m AGL on the haze days were from North China Region and passed through Northeast Heavy Industrial Base in Northeast China.

Wang S.-H., N.-H. Lin, M.-D. Chou, and J.-H. Woo, 2007: Estimate of radiative forcing of Asian biomass-burning aerosols during the period of TRACE-P.J. Geophys. Res.,112,D10222,https://doi.org/10.1029/2006JD007564.10.1029/2006JD007564

605e6ddbdc34a5b86ca03f8922a03eac

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD007564%2Ffull

http://doi.wiley.com/10.1029/2006JD007564[1] The regional radiative impact of biomass-burning aerosols in Asia is estimated using the new and detailed emission data during the experimental period of Transport and Chemical Evolution over the Pacific (TRACE-P) in March 2001. Integration of the USA National Oceanic and Atmospheric Administration (NOAA) Hybrid Single-Particle Lagrangian Integrated Transport model (HYSPLIT) and a solar radiative transfer model (CLIRAD-SW) allow us to simulate the spatial and temporal distributions of black carbon (BC) and organic carbon (OC) aerosols from biomass burning in the South Asian region. It also allows us to estimate further their aerosol optical properties and radiative forcing. We find that an anticyclone over Bay of Bengal dominates the transport of pollutants of the South Asian region. The monthly mean surface concentration of OC and BC is 1.1 0204g m0908083 in this region. Western Myanmar has the maximum value, with the concentration reaching 12.5 0204g m0908083. The monthly mean clear-sky direct shortwave radiative forcing ranges from 0908081.9 to 0.4 W m0908082 at the top of the atmosphere and from 0908080.5 to 09080812.0 W m0908082 at surface, resulting in an increase of the atmospheric heating rate from 0.01 to 0.300°C day0908081. Owing to the spatial distributions of the aerosol optical depth ratio (OC/BC) and the surface albedo, there is a strong gradient of heating rate near the source regions, which may modify local circulations.

Wang X. M., W. H. Chen, D. H. Chen, Z. Y. Wu, and Q. Fan, 2016: Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic Zone (PRDEZ),China.Frontiers of Environmental Science & Engineering,10(2),53-62,https://doi.org/10.1007/s11783-014-0728-z.

10.1007/s11783-014-0728-z

4885871599de2e5f43ddf711eaa36bb8

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs11783-014-0728-z

http://link.springer.com/article/10.1007/s11783-014-0728-z

Wang X. M., X. Ding, X. X. Fu, Q. F. He, S. Y. Wang, F. Bernard, X. Y. Zhao, and D. Wu, 2012: Aerosol scattering coefficients and major chemical compositions of fine particles observed at a rural site in the central Pearl River Delta, South China. Journal of Environmental Sciences, 24(2), 72-77, https://doi.org/10.1016/S1001-0742(11)60730-4.10.1016/S1001-0742(11)60730-4

22783616

7c3e508278888955df4cca34c433564c

http%3A%2F%2Fd.wanfangdata.com.cn%2FPeriodical%2Fjes-e201201008

http://d.wanfangdata.com.cn/Periodical/jes-e201201008

Wang Z. Z., D. Liu, Z. E. Wang, Y. J. Wang, P. Khatri, J. Zhou, T. Takamura, and G. Y. Shi, 2014: Seasonal characteristics of aerosol optical properties at the SKYNET Hefei site (31.90^$\circ$N, 117.17^$\circ$E) from 2007 to 2013. J. Geophys. Res., 119, 6128-6139, https://doi.org/10.1002/2014JD021500.

Wu, D., Coauthors, 2009: Black carbon aerosols and their radiative properties in the Pearl River Delta region.Science in China Series D: Earth Sciences52(9),1152-1163,https://doi.org/10.1007/s11430-009-0115-y.

10.1007/s11430-009-0115-y

b657e83671c1ebbb54422d1872127573

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs11430-009-0115-y

http://link.springer.com/10.1007/s11430-009-0115-yThe climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1–14.8 μg·m 613 and the concentration decreases by about 1 μg·m 613 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m 3 and lower in the rainy season with a multi-year mean of 8.0 μg·m 613 ; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m 613 . It is also shown that monthly mean scattering coefficient derived varies 129 61565 Mm 611 , monthly mean absorption coefficient 32–139 Mm 611 , and monthly mean single scattering albedo 0.71–0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM 10 , PM 2.5 , and PM 1 and the results showed that PM 2.5 took up about 90% of PM 10 and PM 1 accounted for about 68% of PM 2.5 , and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of annual mean is about 4 μg·m 613 .

Xia X., H. Chen, P. Goloub, W. Zhang, B. Chatenet, and P. Wang, 2007b: A compilation of aerosol optical properties and calculation of direct radiative forcing over an urban region in northern China.J. Geophys. Res.,112,D12203,https://doi.org/10.1029/2006JD008119.10.1029/2006JD008119

d0421113ca514a4b83304bd2a9f40d23

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD008119%2Ffull

http://doi.wiley.com/10.1029/2006JD008119[1] Almost 4 years' worth of Aerosol Robotic Network (AERONET) data from Beijing are compiled with historic aerosol data obtained in a few years during the 1980s and 1990s. Aerosol properties, including aerosol optical depth (0304), single scattering albedo (0309) and asymmetry factor (g), show a large day-to-day variation and a distinct seasonal pattern. Aerosol loading is at its maximum during the summer and at its minimum during the winter. Aerosol loading frequently increases gradually from the background level to tens of times that of the background level a few days later, then quickly returns to the background level because of the passage of a weather system. Aerosol optical depth at 550 nm (0304550nm) varies from about 0.28 in 1980 to about 0.68 in 2005, implying a significant increase in aerosol loading during the past 25 years. Historic 0309 and g values are generally in agreement with AERONET data except that aerosol absorption during the winter is quite different. Aerosols induce significant changes in net solar radiation at the surface and at the top of the atmosphere (TOA). The aerosol direct radiative forcing (ADRF) at the surface varies from 09080817.2 W m0908082 in January to 09080863.5 W m0908082 in June and then to 09080818.5 W m0908082 in December. ADRF at the TOA shows a similar seasonal variation to that at the surface, but the value is approximately 2809000942% of the latter. A combination of high aerosol optical depth and strong aerosol absorption leads to significant ADRF in the atmosphere, ranging from 1.9 to 117.6 W m0908082, thus increasing atmospheric heating by 0.3 to 4.6 K/day. The long-term change in aerosol loading in China and its effects on climate and the environment deserve much attention.

Xia X., Z. Li, P. Wang, H. Chen, and M. Cribb, 2007d: Estimation of aerosol effects on surface irradiance based on measurements and radiative transfer model simulations in northern China.J. Geophys. Res.,112,D22S10,https://doi.org/10.1029/2006JD008337.10.1029/2006JD008337

a70ec577cb50561685650abb190caeaa

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD008337%2Fabstract%3Bjsessionid%3DE7B23A361A208261DD4FA96F3E2687E5.f01t04

http://onlinelibrary.wiley.com/doi/10.1029/2006JD008337/full[1] Using 15 months' worth of ground-based broadband and spectral radiation data at Xianghe, a suburban site in northern China, aerosol effects on surface irradiance are explored in this study. Collocated aerosol optical depth (AOD) and surface irradiance measurements made under cloudless sky conditions are first binned according to solar zenith angle. Empirical equations are then developed to describe the relationships between AOD and surface shortwave radiation (SWR) and photosynthetically active radiation (PAR). The equations are finally used to derive quantitative estimates of aerosol effects on surface SWR and PAR. The annual mean aerosol direct radiative forcing (ADRF) values for SWR and PAR derived from measurements are 09080832.8 and 09080816.6 W m0908082, respectively, which are in good agreement with those derived from radiative transfer model simulations. Variations in aerosol concentration not only change the amount of global solar radiation reaching the Earth's surface but also alter the relative proportions of diffuse and direct solar radiation. The annual mean changes in direct and diffuse SWR induced by aerosols are 09080889.6 and 51.0 W m0908082, respectively, and the annual mean changes in direct and diffuse PAR induced by aerosols are 09080851.0 and 29.6 W m0908082, respectively. The effects of regional haze in China on climate and crop production should be further studied.

Xia, X., Coauthors, 2016: Ground-based remote sensing of aerosol climatology in China: Aerosol optical properties,direct radiative effect and its parameterization.Atmos. Environ.,124,243-251,https://doi.org/10.1016/j.atmosenv.2015.05.071.

10.1016/j.atmosenv.2015.05.071

90159266f9f96f53ab120213fa2f7cf6

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231015301424

http://linkinghub.elsevier.com/retrieve/pii/S1352231015301424Spatio-temporal variation of aerosol optical properties and aerosol direct radiative effects (ADRE) are studied based on high quality aerosol data at 21 sunphotometer stations with at least 4-months worth of measurements in China mainland and Hong Kong. A parameterization is proposed to describe the relationship of ADREs to aerosol optical depth at 550nm (AOD) and single scattering albedo at 550nm (SSA). In the middle-east and south China, the maximum AOD is always observed in the burning season, indicating a significant contribution of biomass burning to AOD. Dust aerosols contribute to AOD significantly in spring and their influence decreases from the source regions to the downwind regions. The occurrence frequencies of background level AOD (AOD<0.10) in the middle-east, south and northwest China are very limited (0.4%, 1.3% and 2.8%, respectively). However, it is 15.7% in north China. Atmosphere is pristine in the Tibetan Plateau where 92.0% of AODs are <0.10. Regional mean SSAs at 550nm are 0.89–0.90, although SSAs show substantial site and season dependence. ADREs at the top and bottom of the atmosphere for solar zenith angle of 60±5° are6116–6137Wm 612 and –66–61111Wm 612 , respectively. ADRE efficiency shows slight regional dependence. AOD and SSA together account for more than 94 and 87% of ADRE variability at the bottom and top of the atmosphere. The overall picture of ADRE in China is that aerosols cool the climate system, reduce surface solar radiation and heat the atmosphere.

Xia X. A., P. C. Wang, H. B. Chen, P. Gouloub, and W. X. Zhang, 2005: Ground-based remote sensing of aerosol optical properties over north China in spring.Journal of Remote Sensing9(5),429-437,https://doi.org/10.3321/j.issn:1007-4619.2005.2005.04.014.. (in Chinese with English abstract)10.1360/biodiv.050028

ae9eb31147796b570998922bbadec1ff

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F281582094_Ground-based_remote_sensing_of_aerosol_optical_properties_over_north_China_in_spring

http://www.researchgate.net/publication/281582094_Ground-based_remote_sensing_of_aerosol_optical_properties_over_north_China_in_springAerosol properties including optical depth, size distribution, absorption, etc were studied based on ground-based sun/sky radiometer measurements in the spring of 2001 over North China. Rapid increase of aerosol optical depth and coarse particle concentration, as well as aerosol neutral or anomalous extinction was observed during dusty periods. Anthropogenic emissions also contributed to high aerosol optical depth except dust input over Huabei Plain. The results showed that dust single-scattering albedo was less than those used in the model. Aerosol optical depth and Angstrom parameter in BJ and XH showed close relation, which indicated the regional anthropogenic influence on atmospheric environment. Dust activities might affect aerosol radiative forcing over the downwind regions through input of large volume of dust aerosols, and also through their effects on aerosol physical and radiative properties.

Xia X. G., Z. Q. Li, B. Holben, P. C. Wang, T. Eck, H. B. Chen, M. Cribb, and Y. X. Zhao, 2007a: Aerosol optical properties and radiative effects in the Yangtze Delta region of China.J. Geophys. Res.,112,D22S12,https://doi.org/10.1029/2007JD008859.10.1029/2007JD008859

08288d96398caab233bebec4e60460c0

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2007JD008859%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2007JD008859/full[1] One year's worth of aerosol and surface irradiance data from September 2005 to August 2006 were obtained at Taihu, the second supersite for the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE). Aerosol optical properties derived from measurements by a Sun photometer were analyzed. The aerosol data were used together with surface irradiance data to quantitatively estimate aerosol effects on surface shortwave radiation (SWR) and photosynthetically active radiation (PAR). The annual mean aerosol optical depth at 500 nm is 0.77, and mean 0105ngstrom wavelength exponent is 1.17. The annual mean aerosol single scattering albedo and mean aerosol asymmetry factor at 440 nm are 0.90 and 0.72, respectively. Both parameters show a weak seasonal variation, with small values occurring during the winter and larger values during the summer. Clear positive relationships between relative humidity and aerosol properties suggest aerosol hygroscopic growth greatly modifies aerosol properties. The annual mean aerosol direct radiative forcing at the surface (ADRF) is 09080838.4 W m0908082 and 09080817.8 W m0908082 for SWR and PAR, respectively. Because of moderate absorption, the instantaneous ADRF at the top of the atmosphere derived from CERES SSF data is close to zero. Heavy aerosol loading in this region leads to 090808112.6 W m0908082 and 09080845.5 W m0908082 reduction in direct and global SWR, but 67.1 W m0908082 more diffuse SWR reaching the surface. With regard to PAR, the annual mean differences in global, direct and diffuse irradiance are 09080823.1 W m0908082, 09080865.2 W m0908082 and 42.1 W m0908082 with and without the presence of aerosol, respectively.

Xia X. G., H. B. Chen, Z. Q. Li, P. C. Wang, and J. K. Wang, 2007c: Significant reduction of surface solar irradiance induced by aerosols in a suburban region in northeastern China.J. Geophys. Res.,112,D22S02,https://doi.org/10.1029/2006JD007562.10.1029/2006JD007562

8f978fce6132b75461c004670183714f

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD007562%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/2006JD007562/abstract[1] In the spring of 2005, a Sun photometer and a set of broadband pyranometers were installed in Liaozhong, a suburban region in northeastern China. Aerosol properties derived from Sun photometer measurements and aerosol-induced changes in downwelling shortwave surface irradiances are analyzed in this paper. It is shown that the mean aerosol optical depth (AOD) at 500 nm is 0.63. The day-to-day variation of aerosol optical depth is dramatic, with a maximum daily AOD close to 2.0 and a minimum value close to the background level. Dust activities generally produce heavy aerosol loading characterized by larger particle sizes and less absorption than those observed under normal conditions. The reduction of instantaneous direct shortwave surface irradiance per unit of AOD is 404.5 W m0908082. About 63.8% of this reduction is offset by an increase in diffuse irradiance; consequently, one unit increase in AOD leads to a decrease in global surface irradiance of 146.3 W m0908082. The diurnal aerosol direct radiative forcing efficiency is about 09080847.4 W m0908082. Overall, aerosols reduce about 30 W m0908082 per day of surface net shortwave irradiance in this suburban region.

Xin, J. Y., Coauthors, 2007: Aerosol optical depth (AOD) and gström exponent of aerosols observed by the Chinese Sun Hazemeter Network from August 2004 to September 2005.J. Geophys. Res.,112,D05203,https://doi.org/10.1029/2006JD007075.10.1029/2006JD007075

ad0d3f7abea5194ce542f0ffefbb2c37

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD007075%2Fcitedby

http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGQX201409001004.htm[1] To reduce uncertainties in the quantitative assessment of aerosol effects on regional climate and environmental changes, extensive measurements of aerosol optical properties were made with handheld Sun photometers in the Chinese Sun Hazemeter Network(CSHNET) starting in August 2004. Regional characteristics of the aerosol optical depth(AOD) at 500 nm and ngstrm exponent(a) computed using 405,500, and 650 nm were analyzed for the period of August 2004 to September 2005.The smallest mean AOD($0.15) was found in the Tibetan Plateau where a showed the largest range in value(0.06–0.9). The remote northeast corner of China was the next cleanest region with AODs ranging from 0.19 to 0.21 and with the largest a(1.16–1.79),indicating the presence of fine aerosol particles. The forested sites exhibited moderate values of AOD(0.19–0.51) and a(0.97–1.47). A surprising finding was that the AOD measured at a few desert sites in northern China were relatively low, ranging from0.24 to 0.36, and that a ranged from 0.42 to 0.99, presumably because of several dustblowing episodes during the observation period. The AOD observed over agricultural areas ranges from 0.38 to 0.90; a ranges from 0.55 to 1.11. These values do not differ much from those observed at the inland urban and suburban sites where AOD ranges from 0.50 to 0.69 and a ranges from 0.90 to 1.48. Given the geographic heterogeneity and the rapid increase in urbanization in China, much longer and more extensive observations are required.

Xin J.-Y., Q. Zhang, C.-S. Gong, Y.-S. Wang, W.-P. Du, and Y.-F. Zhao, 2014: Aerosol direct radiative forcing over Shandong Peninsula in East Asia from 2004 to 2011.Atmos. Oceanic Sci. Lett.,7,74-79,https://doi.org/10.3878/j.issn.1674-2834.13. 0072.10.3878/j.issn.1674-2834.13.0072

7e36e12f5a5abfc6f6159ba5fce92fb6

http%3A%2F%2Fwww.cqvip.com%2FQK%2F89435X%2F201401%2F49708627.html

http://www.tandfonline.com/doi/full/10.1080/16742834.2014.11447138在山东半岛的最近的精力旺盛的工业化和都市化，中国，在这个区域上导致了重人为的喷雾器的排放。喷雾器的年度工具光深度(AOD ) ， ? ngstr ? m 代表() ，单个散布的反照率(SSA ) ，喷雾器直接放射的强迫(ARF ) ，表面放射的强迫(SRF ) ，并且 top-of-the (TOA ) 大气的放射的强迫在 20042011 期间记录了分别地 0.67 洠摯汥s

Yang S., G. Y. Shi, B. Wang, H. L. Yang, J. Q. Zhao, and S. G. Qin, 2011: The application of AOD's spectral curve parameter to judgment of aerosol particle size.Journal of Applied Meteorological Science22(3),152-157,https://doi.org/10.3969/j.issn.1001-7313.2011.02.004. (in Chinese)adc10b3f0f53e9ad7fe69771a1198ad4

http%3A%2F%2Fen.cnki.com.cn%2FArticle_en%2FCJFDTotal-YYQX201102006.htm

http://en.cnki.com.cn/Article_en/CJFDTotal-YYQX201102006.htmAerosols play important roles in earth's climate system by scattering and absorbing radiance and changing surface radiation budge,so they are recognized as one of the most important factors inducing global dimming during 1960 to 1990.On the other side,aerosols can also act as cloud condensation nuclei,changing the optical and micro-physical property,altering hydrological cycle.The aerosol particle size is an important factor which could determine the aerosol physical and optical characteristic,so the knowledge of the particle size information is an urgent and necessary job for aerosol research.Angstrom exponent(a) is a convenient parameter for describing particle size,in general,asα1.0,it means coarse particle is dominant;asα1.0,it means fine particle is dominant. However,this application is based on Angstrom power law which is just valid for the Junge size distribution,not suitable for all environments and locations.Improper application would introduce considerable uncertainty and lead to misunderstanding.Fortunately,previous measurements note that when the aerosol doesn't meet Junge size distribution, the Angstrom exponent would vary with wavelength,and the spectral curvature of the Angstrom exponent (α_2,α_1) is useful for describing particle size.Analysis is conducted to find the relationship between these parameter and particle size based on Aeronet Level 2.0 data from Beijing,Taihu,Xinglong,Xianghe sites.The data contain 440 nm,675 nm,870 nm,1020 nm AODs,and particle volume concentration,the data temporal series of each site is more than one year,α,α_2,α_1 are derived by least square method.The results show that although the aerosol is mixed by fine and coarse particle sometimes,αis still larger than 1.5 which indicate that aerosol mainly consists of fine particle in typical Angstrom law.Correspondingly,medianα(0.8α1.2) also appears for fine particle condition at whichαshould be larger than 1.2 in typical Angstrom law.On the other side,whenαis less than 0.75,the aerosol is dominated by coarse particle certainly which is in accord with Angstrom law.It means thatαis a good particle size indicator for coarse particle but not for all conditions.Althoughα_2,α_1 contain particle size information,they are not sufficient for describing particle size just by themselves,they could be nice complement toα.There is significant relationship between particle size andα,α_2,α_1,whenα0.75,α_2-0.5 orα_2-0.5,α_1-1.0,it means that aerosol is dominated by fine particle(V_(fine)/V_(total)0.7);whenα0.75 orα_2-0.25,α_1-1.0,it means that aerosol is dominated by coarse particle(V_(fine)/V_(total)0.2).It has been proposed thatα_2-α_1 is a first approximation of a,which could also be a good particle size indicator.But the examination shows thatα_2-α_1 does not perform as well as expected,especially when 1α_2-α_12,the particle size is very complicated,thusα_2-α_1 provides no assistance to judgment.

Yu, H., Coauthors, 2006: A review of measurement-based assessments of the aerosol direct radiative effect and forcing.Atmos. Chem. Phys.6,613-666,https://doi.org/10.5194/acp-6-613-2006.10.5194/acp-6-613-2006

f3466dcec42fa072deabe339797fdb2f

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F2699398

http://www.atmos-chem-phys.net/6/613/2006/Aerosols affect the Earth's energy budget directly by scattering and absorbing radiation and indirectly by acting as cloud condensation nuclei and, thereby, affecting cloud properties. However, large uncertainties exist in current estimates of aerosol forcing because of incomplete knowledge concerning the distribution and the physical and chemical properties of aerosols as well as aerosol-cloud interactions. In recent years, a great deal of effort has gone into improving measurements and datasets. It is thus feasible to shift the estimates of aerosol forcing from largely model-based to increasingly measurement-based. Our goal is to assess current observational capabilities and identify uncertainties in the aerosol direct forcing through comparisons of different methods with independent sources of uncertainties. Here we assess the aerosol optical depth (t), direct radiative effect (DRE) by natural and anthropogenic aerosols, and direct climate forcing (DCF) by anthropogenic aerosols, focusing on satellite and ground-based measurements supplemented by global chemical transport model (CTM) simulations. The multi-spectral MODIS measures global distributions of aerosol optical depth (t) on a daily scale, with a high accuracy of 0.030.05t over ocean. The annual average t is about 0.14 over global ocean, of which about 21%7% is contributed by human activities, as estimated by MODIS fine-mode fraction. The multi-angle MISR derives an annual average AOD of 0.23 over global land with an uncertainty of ~20% or 0.05. These high-accuracy aerosol products and broadband flux measurements from CERES make it feasible to obtain observational constraints for the aerosol direct effect, especially over global the ocean. A number of measurement-based approaches estimate the clear-sky DRE (on solar radiation) at the top-of-atmosphere (TOA) to be about -5.50.2 Wm-2 (median standard error from various methods) over the global ocean. Accounting for thin cirrus contamination of the satellite derived aerosol field will reduce the TOA DRE to -5.0 Wm-2. Because of a lack of measurements of aerosol absorption and difficulty in characterizing land surface reflection, estimates of DRE over land and at the ocean surface are currently realized through a combination of satellite retrievals, surface measurements, and model simulations, and are less constrained. Over the oceans the surface DRE is estimated to be -8.80.7 Wm-2. Over land, an integration of satellite retrievals and model simulations derives a DRE of -4.90.7 Wm-2 and -11.81.9 Wm-2 at the TOA and surface, respectively. CTM simulations derive a wide range of DRE estimates that on average are smaller than the measurement-based DRE by about 30-40%, even after accounting for thin cirrus and cloud contamination. <P style="line-height: 20px;"> A number of issues remain. Current estimates of the aerosol direct effect over land are poorly constrained. Uncertainties of DRE estimates are also larger on regional scales than on a global scale and large discrepancies exist between different approaches. The characterization of aerosol absorption and vertical distribution remains challenging. The aerosol direct effect in the thermal infrared range and in cloudy conditions remains relatively unexplored and quite uncertain, because of a lack of global systematic aerosol vertical profile measurements. A coordinated research strategy needs to be developed for integration and assimilation of satellite measurements into models to constrain model simulations. Enhanced measurement capabilities in the next few years and high-level scientific cooperation will further advance our knowledge.

Zhang D., Y. Wang, Y. R. Feng, and Y. C. Fang, 2014: Analysis and forecasting of high-humidity weather in Guangdong in February and March.Meteorological Science and Technology42(3),302-308,https://doi.org/10.3969/j.issn.1671-6345.2014.02.021. (in Chinese)ac4ba1b692a332276baa22689c805f94

http%3A%2F%2Fen.cnki.com.cn%2FArticle_en%2FCJFDTotal-QXKJ201402022.htm

http://en.cnki.com.cn/Article_en/CJFDTotal-QXKJ201402022.htmDuring the transition season between winter and spring in Guangdong Province,many objects such as indoor floors,walls and glasses easily become damp and are often covered by a thin clay of condensed water.An analysis is made of such five cases of the special high-humidity weather during February and March in 2012in the aspects of physical processes and circulation patterns,air temperature and humidity characteristics,etc.The results indicates:after the termination of the influence of cold air, warm and wet air affects Guangdong when the dew point of outdoor air is higher than the indoor object temperature,and a high-humidity weather event appears on the background of cold air making a sudden turn into warm air.During the transition season between winter and spring,when the high pressure ridge weakens rapidly,meanwhile there is obvious southerly air flow on 925hPa,it is necessary to consider whether there appears a high-humidity phenomenon during daily weather forecasting;the rapid rise of air temperature is the necessary condition for the high-humidity phenomenon;the trend of future dew point should be selectively analyzed.The high-humidity phenomenon normally disappears in two ways:cold ending and warm ending.Namely,Guangdong is affected by new cold air and the air temperature and dew point decrease dramatically,and the dew point is lower than the indoor object temperature;or air temperature rises up and lasts for a certain time period and the indoor object temperature is higher than the outdoor air dew point.

Zheng, M., Coauthors, 2011: Sources of excess urban carbonaceous aerosol in the Pearl River Delta Region,China.Atmos. Environ.,45,1175-1182,https://doi.org/10.1016/j.atmosenv.2010.09.041.. 10.1016/j.atmosenv.2010.09.041

3d2a670795f59472907cc8cd25579c01

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231010008174

http://linkinghub.elsevier.com/retrieve/pii/S1352231010008174Carbonaceous aerosol is one of the important constituents of fine particulate matter (PM 2.5 ) in southern China, including the Pearl River Delta (PRD) region and Hong Kong (HK). During the study period (October and December of 2002, and March and June of 2003), the monthly average organic carbon (OC) ranged from 3.52 to 7.87μgm 613 in Hong Kong and 4.14–20.19μgm 613 in the PRD from simultaneous measurements at three sites in HK and four sites in the PRD. Compared to the PRD, the spatial distribution of carbonaceous aerosol in Hong Kong was relatively homogeneous. Sources contributing to excess OC in the PRD were examined, which is the difference between OC concentrations measured at the PRD sites to the average level in Hong Kong. Eight primary sources contributing to excess OC were identified with chemical mass balance modeling in a combination with molecular markers analyzed by gas chromatography/mass spectrometry. Excess OC at Guangzhou, the capital city of Guangdong province, was consistently high, ranging from 9.77 to 13.6μgm 613 . Four primary sources including gasoline engine exhaust, diesel engine exhaust, biomass burning, and coal combustion accounted for more than 50% of excess OC in the PRD, especially in December (up to 76%). Mobile source emissions alone can contribute about 30% of excess OC. The unexplained or other excess OC was the highest at the rural site, but in general less than 20% at other sites. The coal combustion source contribution was unique in that it exhibited relatively homogeneous spatial distribution, indicating it was still an important source of carbonaceous aerosol in the PRD (17% of excess OC) during the study period. This analysis revealed that primary emissions are important sources of excess OC in the PRD and there is a need to reduce the emissions of mobile sources, biomass burning, and coal combustion in order to improve air quality in southern China.

Zhu J., H. Z. Che, X. Xia, H. B. Chen, P. Goloub, and W. X. Zhang, 2014: Column-integrated aerosol optical and physical properties at a regional background atmosphere in North China Plain.Atmos. Environ.,84,54-64,https://doi.org/10.1016/j.atmosenv.2013.11.019..10.1016/j.atmosenv.2013.11.019

314fae96e256b665d372d8691b4324f7

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231013008480

http://linkinghub.elsevier.com/retrieve/pii/S1352231013008480The AERONET level 2.0 data at Xinglong station from February 2006 to July 2011 were used to characterize the aerosol optical and physical properties, including temporal variability, aerosol absorption, classification and properties under dust and haze conditions. The annual mean aerosol optical depth (AOD) and extinction Angstrom exponent (EAE) are 0.28±0.30 and 1.07±0.38, respectively. The seasonal variations of AOD 440nm are higher in spring (0.40±0.3) and summer (0.40±0.42) than in autumn (0.20±0.22) and winter (0.19±0.21). The EAE is low in spring (0.96±0.43) and high in summer (1.22±0.38). The EAE is 651.25 with an absorption Angstrom exponent (AAE) of 651.0–1.5 in Xinglong, which indicates that the dominant type is mixed aerosol (accounting for 88.2% at AAE>1.0). Almost all of the dust observations occurred in spring. The volume concentrations of both fine and coarse mode particles increase with increasing AOD. In spring, the increase of coarse particles is greater than that of fine aerosols; however, the reverse phenomenon is observed for other seasons. The high AOD at Xinglong could be associated with the growth of fine mode aerosols and addition of coarse mode particles. This background station is not only impacted by dust aerosols from northwest China and south Mongolia but also influenced by long-range transportation of anthropogenic aerosols from south urban and industrialized regions. The mean AOD was 1.49 on the dust day, while AOD was 1.10 on the haze day. The mean EAEs were 0.09 and 1.43 on dust and haze days, respectively.

Zhuang B. L., S. Li, T. J. Wang, J. J. Deng, M. Xie, C. Q. Yin, and J. L. Zhu, 2013: Direct radiative forcing and climate effects of anthropogenic aerosols with different mixing states over China.Atmos. Environ.,79,349-361,https://doi.org/10.1016/j.atmosenv.2013.07.004..10.1016/j.atmosenv.2013.07.004

dbbbea521fe913c6cb7390468a4ffbf8

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231013005256

http://linkinghub.elsevier.com/retrieve/pii/S1352231013005256An online coupled regional climate and chemistry model was used to investigate the direct effects of anthropogenic aerosols (sulfate, nitrate, black carbon BC and organic carbon OC) with different mixing states over China. Three mixing assumptions were considered, including external (EM), internal (IM, BC-core surrounded by well mixed scattering-shells) and partially internal (PIM, 32.2% of sulfate and nitrate, 35.5% of BC and 48.5% of OC were internally mixed) mixtures. Results indicated that high levels of anthropogenic aerosols were found in Southwest and Central to East China. Regional mean surface loadings of sulfate, nitrate, BC, primary OC over China were 9.56, 3.64, 2.30, and 2.99 mu g m(-3), respectively. PIM-aerosol optical depth and single scattering albedo, which were consistent with AERONET and satellite observations, were 0.51 +/- 0.37 and 0.95 +/- 0.02 in Central to East China, implying that proportions of internally mixed aerosols in PIM were reasonable to some degrees. Both aerosol direct radiative forcing (DRF) and corresponding climate responses were sensitive to aerosol mixing states and BC/OC hygroscopicities. The more BC was internally mixed or hydrophilic, the more solar radiation was absorbed, thus leading to more decreases in cloud amount (CA) and subsequently less surface cooling. Combining with the uncertainties of BC/OC hygroscopicities, regional mean PIM-aerosol DRF at the top of atmosphere ranged from -0.78 to -0.61 W m(-2) in all-sky and from -5.24 to -4.95 W m(-2) in clear-sky. Additionally, responses of cloud amount and water path, total column absorbed solar radiation (TCASR), surface air temperature and precipitation (TP) to PIM-aerosol DRFs over China were about -0.45 similar to -0.37%, -0.44 similar to -0.32 g m(-2), +0.69 similar to +0.72 W m(-2), -0.13 similar to -0.11 K and -4.56 similar to -4.29%, respectively. These responses were also sensitive to the lateral boundary condition perturbations especially for CA, TCASR and TP, while DRFs themselves were not. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.