doi:10.1007/s00376-017-7029-y

Chen M. Y., P. P. Xie, J. E. Janowiak, and P. A. Arkin, 2002: Global land precipitation: A 50-yr monthly analysis based on gauge observations. Journal of Hydrometeorology, 3, 249-266, .https://doi.org/10.1175/1525-7541(2002)003<0249:GLPAYM>2.0,CO;2

10.1175/1525-7541(2002)003<0249:GLPAYM>2.0.CO;2

02ed5cbd2cfb77e05229e28c9cb641ca

http%3A%2F%2Fjpe.oxfordjournals.org%2Fexternal-ref%3Faccess_num%3D10.1175%2F1525-7541%282002%290032.0.CO%3B2%26amp%3Blink_type%3DDOI

http://journals.ametsoc.org/doi/abs/10.1175/1525-7541%282002%29003%3C0249%3AGLPAYM%3E2.0.CO%3B2

Ding Q. H., B. Wang, 2005: Circumglobal teleconnection in the northern hemisphere summer.J. Climate,18,3483-3505, https://doi.org/10.1175/JCLI3473.1.

10.1175/JCLI3473.1

e18c4652063ff9837f9b242cae362904

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2005AGUSM.A33B..01D

http://journals.ametsoc.org/doi/abs/10.1175/JCLI3473.1Analysis of the 56-yr NCEP09“NCAR reanalysis data reveals a recurrent circumglobal teleconnection (CGT) pattern in the summertime midlatitude circulation of the Northern Hemisphere. This pattern represents the second leading empirical orthogonal function of interannual variability of the upper-tropospheric circulation. The CGT, having a zonal wavenumber-5 structure, is primarily positioned within a waveguide that is associated with the westerly jet stream. The spatial phases of CGT tend to lock to preferred longitudes. The geographically phase-locked patterns bear close similarity during June, August, and September, but the pattern in July shows shorter wavelengths in the North Pacific09“North America sector. The CGT is accompanied by significant rainfall and surface air temperature anomalies in the continental regions of western Europe, European Russia, India, east Asia, and North America. This implies that the CGT may be a source of climate variability and predictability in the above-mentioned midlatitude regions. The CGT has significant correlations with the Indian summer monsoon (ISM) and El Ni01±o09“Southern Oscillation (ENSO). However, in normal ISM years the CGT09“ENSO correlation disappears; on the other hand, in the absence of El Ni01±o or La Ni01±a, the CGT09“ISM correlation remains significant. It is suggested that the ISM acts as a 0904conductor0909 connecting the CGT and ENSO. When the interaction between the ISM and ENSO is active, ENSO may influence northern China via the ISM and the CGT. Additionally, the variability of the CGT has no significant association with the Arctic Oscillation and the variability of the western North Pacific summer monsoon. The circulation of the wave train shows a barotropic structure everywhere except the cell located to the northwest of India, where a baroclinic circulation structure dominates. Two possible scenarios are proposed. The abnormal ISM may excite an anomalous west-central Asian high and downstream Rossby wave train extending to the North Pacific and North America. On the other hand, a wave train that is excited in the jet exit region of the North Atlantic may affect the west-central Asian high and, thus, the intensity of the ISM. It is hypothesized that the interaction between the global wave train and the ISM heat source may be instrumental in maintaining the boreal summer CGT.

Enomoto T., 2004: Interannual variability of the bonin high associated with the propagation of Rossby waves along the Asian jet.J. Meteor. Soc. Japan,82,1019-1034, 2004. 1019.https://doi.org/10.2151/jmsj.

10.2151/jmsj.2004.1019

ecf4888ad33f75476c33e2fdd06d4e8a

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F110001803127

http://joi.jlc.jst.go.jp/JST.JSTAGE/jmsj/2004.1019?from=CrossRefInterannual variability of the Ogasawara (Bonin) high in August is examined in relation to propagation of stationary Rossby waves along the Asian jet using monthly averages from the NCEP/NCAR reanalysis dataset for 52 years. The perturbation kinetic energy at 200 hPa is used as a measure of the activity of stationary Rossby waves along the Asian jet. Composite maps of five relatively wavy-jet years with close phases show an enhanced anticyclone over Japan. This anomalous ridge has a maximum amplitude at 250 hPa and extends throughout the troposphere with little zonal and slight northward tilts. Wave-activity and isentropic potential vorticity analyses clearly show that the ridge is created by the propagation of stationary Rossby waves to Japan. The anomalous ridge accompanies a positive temperature anomaly over Japan in the entire troposphere. A negative temperature anomaly to the east of Japan is also created in the lower troposphere by the northerly flow between the anomalous ridge and trough. By contrast, the equivalent-barotropic ridge over Japan is very weak in the zonal-jet years. Although Rossby waves are as strong as those in the wavy-jet years near the source, they are found to converge to the southeast of its source with little further downstream propagation. This contrast in the behaviour of Rossby waves is consistent with the intensity of the Asian jet to the east of 90ºE. The composite analysis suggests that the enhancement of a deep ridge near Japan is regulated by the intensity of the Asian jet. The composite analysis study conducted here emphasizes the importance of the propagation of stationary Rossby waves along the Asian jet for the late summer climate in northeastern Asia.

Enomoto T., B. J. Hoskins, and Y. Matsuda, 2003: The formation mechanism of the Bonin high in August.Quart. J. Roy. Meteor. Soc.,129,157-178, https://doi.org/10.1256/qj.01.211.

10.1256/qj.01.211

1c51821855266189851ad2c1a89d7910

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1256%2Fqj.01.211%2Ffull

http://doi.wiley.com/10.1256/qj.01.211Abstract The Bonin high is a subtropical anticyclone that is predominant near Japan in the summer. This anticyclone is associated with an equivalent-barotropic structure, often extending throughout the entire troposphere. Although the equivalent-barotropic structure of the Bonin high has been known for years among synopticians because of its importance to the summer climate in east Asia, there are few dynamical explanations for such a structure. The present paper attempts to provide a formation mechanism for the deep ridge near Japan. We propose a new hypothesis that this equivalent-barotropic ridge near Japan is formed as a result of the propagation of stationary Rossby waves along the Asian jet in the upper troposphere ( he Silk Road pattern). First, the monthly mean climatology is examined in order to demonstrate this hypothesis. It is shown that the enhanced Asian jet in August is favourable for the propagation of stationary Rossby waves and that the regions of descent over the eastern Mediterranean Sea and the Aral Sea act as two major wave sources. Second, a primitive-equation model is used to simulate the climatology of August. The model successfully simulates the Bonin high with an equivalent-barotropic structure. The upper-tropospheric ridge is found to be enhanced by a height anomaly of more than 80 m at 200 hPa, when a wave packet arrives. Sensitivity experiments are conducted to show that the removal of the diabatic cooling over the Asian jet suppresses the Silk Road pattern and formation of an equivalent-barotropic ridge near Japan, while the removal of the diabatic heating in the western Pacific does not. Copyright 2003 Royal Meteorological Society

Grunseich G., B. Wang, 2016: Arctic sea ice patterns driven by the Asian summer monsoon.J. Climate,29,9097-9112, https://doi.org/10.1175/JCLI-D-16-0207.1.

10.1175/JCLI-D-16-0207.1

fbbb894ab3951381fd43fdf05f710b4b

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F308186763_Arctic_sea_ice_patterns_driven_by_the_Asian_Summer_Monsoon

http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0207.1react-text: 395 Century-long efforts have been devoted to seasonal forecast of Indian summer monsoon rainfall (ISMR). Most studies of seasonal forecast so far have focused on predicting the total amount of summer rainfall averaged over the entire India (i.e., all Indian rainfall index-AIRI). However, it is practically more useful to forecast anomalous seasonal rainfall distribution (anomaly pattern) across... /react-text react-text: 396 /react-text [Show full abstract]

Guan Z. Y., T. Yamagata, 2003: The unusual summer of 1994 in East Asia: IOD teleconnections,Geophys. Res. Lett.,30,1544, https://doi.org/10.1029/2002GL016831.

10.1029/2002GL016831

d9a0f1a631c4563882e61b1edb5496eb

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2002GL016831%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2002GL016831/pdfAn extremely hot and dry summer of 1994 was reported in East Asian countries. Using observational data, we have demonstrated that the Indian Ocean Dipole (IOD) is at least one possible cause of the abnormal East Asian summer climate. An anomalous cyclonic circulation over the western Pacific and the southern China weakened the monsoonal northward flow in the lower troposphere. An anomalous anticyclonic circulation with the equivalent barotropic structure around Japan, Korea and the northeastern part of China caused the hot and dry summer of 1994. This accumulation of the lower potential vorticity in the Far East is related to the wave activity from the Mediterranean/Sahara region. The monsoon-desert mechanism connects a Rossby wave source with the IOD-induced diabatic heating around the Bay of Bengal. Another Rossby wave-train pattern was generated in the upper troposphere and propagates northeastward from the southern China. Both the Rossby wave patterns influenced the circulation changes over East Asia.

Guo D., Y. Q. Gao, I. Bethke, D. Y. Gong, O. M. Johannessen, and H. J. Wang, 2014: Mechanism on how the spring Arctic sea ice impacts the East Asian summer monsoon.Theor. Appl. Climatol.,115,107-119, https://doi.org/10.1007/s00704-013-0872-6.

10.1007/s00704-013-0872-6

e974c7d3c1cbd752fc0be37fda1807fe

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs00704-013-0872-6

http://link.springer.com/10.1007/s00704-013-0872-6Observational analysis and purposely designed coupled atmosphere cean (AOGCM) and atmosphere-only (AGCM) model simulations are used together to investigate a new mechanism describing how spring Arctic sea ice impacts the East Asian summer monsoon (EASM). Consistent with previous studies, analysis of observational data from 1979 to 2009 show that spring Arctic sea ice is significantly linked to the EASM on inter-annual timescales. Results of a multivariate Empirical Orthogonal Function analysis reveal that sea surface temperature (SST) changes in the North Pacific play a mediating role for the inter-seasonal connection between spring Arctic sea ice and the EASM. Large-scale atmospheric circulation and precipitation changes are consistent with the SST changes. The mechanism found in the observational data is confirmed by the numerical experiments and can be described as follows: spring Arctic sea ice anomalies cause atmospheric circulation anomalies, which, in turn, cause SST anomalies in the North Pacific. The SST anomalies can persist into summer and then impact the summer monsoon circulation and precipitation over East Asia. The mediating role of SST changes is highlighted by the result that only the AOGCM, but not the AGCM, reproduces the observed sea ice-EASM linkage.

He S.-P., 2015: Potential connection between the Australian summer monsoon circulation and summer precipitation over central China.Atmospheric and Oceanic Science Letters,8,120-126, https://doi.org/10.3878/AOSL20140091.

10.3878/AOSL20140091

47ce8a5fcbd3381ef146913fa5506b8a

http%3A%2F%2Fwww.tandfonline.com%2Fdoi%2Fabs%2F10.3878%2FAOSL20140091

http://www.tandfonline.com/doi/full/10.1080/16742834.2015.11447248这研究在华中上调查了在澳大利亚的夏天季风(ASM ) 和夏天降水之间的连接。它被发现那，跟随 weaker-than-normal ASM，东方亚洲夏天季风和西方的向北和平的副热带的高度趋于更强壮，让步异常向北方从西方的太平洋要搬运到华中的潮湿。而且，异常 upwelling 运动超过 3037.5 出现

Hong X. W., R. Y. Lu, 2016: The meridional displacement of the summer Asian jet,silk road pattern,and tropical SST anomalies. J. Climate,29, 3753-3766,.https://doi.org/10.1175/JCLI-D-15-0541.1

Hsu H.-H., X. Liu, 2003: Relationship between the Tibetan Plateau heating and East Asian summer monsoon rainfall,Geophys. Res. Lett.,30,2066, https://doi.org/10.1029/2003GL017909.

10.1029/2003GL017909

8fea788712753f702d00abd5311183ed

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2003GL017909%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2003GL017909/fullThis study reveals the close correspondence between the interannual variability of the dominant East Asian summer rainfall pattern and the diabatic heating over the Tibetan Plateau in both spring and summer. The heating fluctuation over the Tibetan Plateau is associated with two wave-like circulation patterns, which bear the characteristics of forced Rossby wave emanating away from the deep heating. The wave-like pattern in turn affects the East Asian summer rainfall. Because of the persistent heating over the Tibetan Plateau from spring to summer and its possible effect on the surrounding areas, the heating index defined in this study can be used as a good predictor for the JJA heating and precipitation distributions. Evidences shown suggest that external conditions other than the SST anomaly must be considered to understand the interannual variability of the East Asian summer rainfall.

Hsu H.-H., S.-M. Lin, 2007: Asymmetry of the tripole rainfall pattern during the East Asian summer.J. Climate,20,4443-4458, https://doi.org/10.1175/JCLI4246.1.

10.1175/JCLI4246.1

56eb76d8f87ccb1f21008b0d16c95594

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2007jcli...20.4443h

http://journals.ametsoc.org/doi/abs/10.1175/JCLI4246.1This study investigates the tripole rainfall pattern in East Asia during the northern summer. The tripole pattern is characterized by a zonally elongated and meridionally banded structure with signs changing alternatively from 2000° to 5000°N along the East Asian coast. The positive (negative) phase of the pattern is characterized by more (less) rainfall in central-eastern China, Japan, and South Korea, and less (more) rainfall in northern and southern China. Asymmetry between the positive and negative phases is one of the key findings of this study. The tripole pattern is closely associated with two wavelike patterns: the Pacific09“Japan pattern and the Silk Road pattern. The former, which emanates from the tropical western Pacific to extratropical East Asia, is more evident in the positive phase, while the latter, emanating across the Eurasian continent, is more evident in the negative phase. The positive phase appears to have a stronger tropical connection, while the negative phase has a stronger extratropical connection. The positive and negative phases are associated with the positive and negative SSTA in the equatorial eastern Pacific, respectively. It is suggested that in the positive phase the zonally oriented overturning circulation driven by the positive SSTA in the equatorial eastern Pacific induces heating anomalies in the tropical western Pacific, which in turn triggers a wavelike pattern emanating northward toward extratropical East Asia. This indirect SSTA effect is not evident in the negative phase, which is predominantly affected by the extratropical Eurasian wavelike perturbations. On the other hand, anomalous heating over the eastern Tibetan Plateau seems to induce the eastward-propagating wavelike structure in both phases. It is suggested that the tripole pattern is a result of the amplification of an intrinsic dynamic mode that can be triggered by various factors despite their different origins.

Huang R. H., F. Y. Sun, 1992: Impacts of the tropical western Pacific on the East Asian summer monsoon.J. Meteor. Soc. Japan,70,243-256, https://doi.org/10.2151/jmsj1965.70.1B_243.

10.1175/1520-0469(1992)049<0256:PAPIAP>2.0.CO;2

1aaabaa5e72c71c10dbbd6497a52bf19

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F40000634875

https://www.jstage.jst.go.jp/article/jmsj1965/70/1B/70_1B_243/_articleIn this paper, the impacts of the convective activities in the western Pacific warm pool on the interannual and intraseasonal variations of the summer monsoon in East Asia are analyzed by using the observed data for 12 summers from 1978 to 1989. The analyzed results show that both interannual and intraseasonal variabilities of the East Asian summer monsoon are greatly influenced by the convective activities in the warm pool. Generally, the monsoon rainfall is below normal in East Asia and the abrupt change of the monsoon circulation is obvious in the summer of strong convective activities around the Philippines. The impacts of the convective activities in the warm pool on the summer monsoon in East Asia and the East Asia/Pacific teleconnection pattern of summer circulation anomalies due to the convection are discussed by using the theory of planetary wave propagation and the numerical modelling by the IAP-GCM, respectively.

Ju L.-X., Z.-W. Han, 2013: Impact of different East Asian summer monsoon circulations on aerosol-induced climatic effects.Atmospheric and Oceanic Science Letters,6,227-232, https://doi.org/10.3878/j.issn.1674-2834.13.0018.

10.3878/j.issn.1674-2834.13.0018

2f14eb8fe207f1fc94bd2fc29e16ddbc

http%3A%2F%2Fd.wanfangdata.com.cn%2FPeriodical_dqhhykxkb201305002.aspx

http://www.tandfonline.com/doi/full/10.1080/16742834.2013.11447086weak (2003) and a strong (2006) East Asian summer monsoon (EASM) circulation were simulated using a high-resolution regional climate model (RegCM3). Results showed that the atmospheric circulations of summer monsoon have direct relations with transport of aerosols and their climatic effects. Both the top-of-the-atmosphere (TOA) and the surface-negative radiative forcing of aerosols were stronger in weak EASM circulations. The main difference in aerosol-induced negative forcing in two summers varied between 2 and 14 W m from the Sichuan Basin to North China, where a maximum in aerosol-induced negative forcing was also noticed in the EASM-dominated areas. The spatial difference in the simulated aerosol optical depth (AOD) in two summers generally showed the similar pictures. Surface cooling effects induced by aerosols were spatially more uniform in weak EASM circulations and cooler by about 1-4.5ºC. A preliminary analysis here indicated that a weaker low-level wind speed not conducive to the transport and diffusion of aerosols could make more contributions to the differences in the two circulations.

Kalnay, E., Coauthors, 1996: The NCEP/NCAR 40-year reanalysis project. Bull. Amer. Meteor. Soc., 77, 437-471, https://doi.org/10.1175/1520-0477(1996)077<0437:TNYRP>2.0,CO;2.

10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2

9bfeacc7ab553b364e43408563ad850b

http%3A%2F%2Fintl-icb.oxfordjournals.org%2Fexternal-ref%3Faccess_num%3D10.1175%2F1520-0477%281996%290772.0.CO%3B2%26amp%3Blink_type%3DDOI

http://journals.ametsoc.org/doi/abs/10.1175/1520-0477%281996%29077%3C0437%3ATNYRP%3E2.0.CO%3B2

Kosaka Y., H. Nakamura, 2006: Structure and dynamics of the summertime Pacific-Japan teleconnection pattern.Quart. J. Roy. Meteor. Soc.,132,2009-2030, https://doi.org/10.1256/qj.05.204.

10.1256/qj.05.204

2dc5d851f039ea3a6f8e45fc9b82fbd2

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1256%2Fqj.05.204%2Ffull

http://doi.wiley.com/10.1256/qj.05.204Abstract Convective activity over the tropical western Pacific is known to influence the extratropical circulation over East Asia in the boreal summer in the form of teleconnection, called the ‘Pacific–Japan (PJ) pattern’, but its structure and dynamics have not yet been studied in depth. In this study, a composite analysis is performed for 32 monthly events of enhanced convection observed to the east of the Philippines. The composited monthly mean vorticity anomalies associated with the PJ pattern are elongated zonally with a distinct poleward tilt with height. This structure differs fundamentally from a combination of the first baroclinic mode in the tropics and the barotropic structure in midlatitudes, as has widely been accepted as a conceptual model of the PJ pattern. A wave-activity flux points polewards only in the lower troposphere, indicating that Rossby wave teleconnection occurs primarily through a low-level south-westerly jet. Those tilted anomalies over the western Pacific can effectively gain kinetic energy in the exits of the mean jet streams in the upper and lower troposphere and available potential energy (APE) in the presence of the vertically sheared jets. The enhanced convection can generate APE effectively, and the associated low-level anomalous circulation acts to increase moisture supply into the convective region while enhancing evaporation from the pre-warmed ocean surface. It is thus hypothesized that the PJ pattern may be regarded as a dynamical mode that can be effectively excited in the zonally asymmetric baroclinic mean flow associated with the Asian summer monsoon with an efficient self-sustaining mechanism through moist processes. Copyright 08 2006 Royal Meteorological Society

Lau K.-M., H. Y. Weng, 2001: Coherent modes of global SST and summer rainfall over China: An assessment of the regional impacts of the 1997-98 El Niño. J. Climate, 14, 1294-1308, https://doi.org/10.1175/1520-0442(2001)014<1294:CMOGSA>2.0,CO;2.10.1175/1520-0442(2001)0142.0.CO;2

b4336635ea269347aeea28e54d5108c4

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F10013127219%2F

http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%282001%29014%3C1294%3ACMOGSA%3E2.0.CO%3B2In this paper, the authors have identified three coherent modes of summertime rainfall variability over China and global sea surface temperature (SST) for the period of 1955-98 by Singular Value Decomposition. Based on these modes, the impacts of the 1997-98 El Ni09o on major drought and flood occurrences over China have been assessed. The first mode can be identified with the growing phase of El Ni09o superimposed on a warming trend since the mid-1950s. This mode strongly influences rainfall over northern China. The second mode comprises a quasi-biennial (QB) variability manifested in alternate wet and dry years over the Yangtze River Valley (YRV) of central China. The third mode is dominated by a quasi-decadal oscillation in eastern China between the Yangtze River and the Yellow River, with an opposite tendency in southern China.Using a mode-by-mode reconstruction, the contributions of these leading modes to the 1997 and 1998 observed rainfall anomalies are evaluated. It is found that the severe drought in northern China, and to a lesser degree the flood in southern China, in 1997 is likely a result of the influence of anomalous SST forcing during the growing phase of the 1997-98 El Ni09o. The severe flood over YRV in 1998 is associated with the biennial tendency of basin-scale SST anomaly during the transition from El Ni09o to La Ni09a in 1997-98. In addition, the prolonged dry tendency over northern China and wet tendency over YRV since the 1970s may be associated with a long-term warming trend in the tropical Indian Ocean and western Pacific. The long-term dry background exacerbated the drought situation over northern China in 1997, and the wet background exacerbated the flood situation over YRV in 1998, under the impacts of the 1997-98 El Ni09o. In contrast, the rainfall variability in southern China is most chaotic, with no clear dominance of either El Ni09o or QB signals. The significance, reliability, and stability of these results are also discussed.

Lu R.-Y., J.-H. Oh, and B.-J. Kim, 2002: A teleconnection pattern in upper-level meridional wind over the North African and Eurasian continent in summer. Tellus A 54, 44-55. http://dx.doi.org/10.3402/tellusa.v54i1.12122.10.1034/j.1600-0870.2002.00248.x

ca72f33b50a1704343239c73d29e6b23

http%3A%2F%2Fwww.tandfonline.com%2Fdoi%2Fabs%2F10.3402%2Ftellusa.v54i1.12122

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0870.2002.00248.x/citedbyOne-point correlation analysis on upper-level meridional wind identified the existence of a teleconnection pattern in July, which emerges from North Africa to East Asia along the westerly jet in the middle latitudes. We examined the spatial and temporal structures of this teleconnection pattern, and found the unique characteristics rather different from the patterns in other elements such as geopotential height, streamfunction and vorticity. We also investigated the relationship between this teleconnection and precipitation, and suggested that the teleconnection is a possible linkage of the EASM to the Indian monsoon, and even to subtropical heating anomalies over Atlantic.

Matsumura S., K. Yamazaki, 2012: Eurasian subarctic summer climate in response to anomalous snow cover.J. Climate,25,1305-1317, https://doi.org/10.1175/2011JCLI4116.1.

10.1175/2011JCLI4116.1

fcdc5ac21691461825fafd08de0ac944

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2012JCli...25.1305M

http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4116.1The summer climate in northern Eurasia is examined as a function of anomalous snow cover and processes associated with land-atmosphere coupling, based on a composite analysis using observational and reanalysis data. The analysis confirms that the snow-hydrological effect, which is enhanced soil moisture persisting later into the summer and contributing to cooling and precipitation recycling, is active in eastern Siberia and contributes to the formation of the subpolar jet through the thermal wind relationship in early snowmelt years. Strong anticyclonic differences (early - late snowmelt years) with a baroclinic structure form over eastern Siberia as a result of surface heating through the snow-hydrological effect in early snowmelt years. Surface heating contributes to the development of thermally generated stationary Rossby waves that propagate eastward to eastern Siberia. Rossby wave activity is maintained into early autumn, together with cyclonic differences over far eastern Siberia, in conjunction with the early appearance of snow cover in this region. The anticyclonic differences over eastern Siberia act like a blocking anticyclone, thereby strengthening upstream storm track activity. Furthermore, it is possible that surface anticyclonic differences over the Arctic contribute to year-to-year variability of summer Arctic sea ice concentration along the Siberian coast. The results suggest that variations in northern Eurasian snow cover and associated land-atmosphere coupling processes have important implications for the predictability of Eurasian subarctic summer climate.

Matsumura S., X. D. Zhang, and K. Yamazaki, 2014: Summer Arctic atmospheric circulation response to spring Eurasian snow cover and its possible linkage to accelerated sea ice decrease.J. Climate,27,6551-6558, https://doi.org/10.1175/JCLI-D-13-00549.1.

10.1175/JCLI-D-13-00549.1

eb65879038b9a251573f335ebbaccbc7

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F120005549583%2Fja%2F

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00549.1Anticyclonic circulation has intensified over the Arctic Ocean in summer during recent decades. However, the underlying mechanism is, as yet, not well understood. Here, it is shown that earlier spring Eurasian snowmelt leads to anomalously negative sea level pressure (SLP) over Eurasia and positive SLP over the Arctic, which has strong projection on the negative phase of the northern annular mode (NAM) in summer through the wave-mean flow interaction. Specifically, earlier spring snowmelt over Eurasia leads to a warmer land surface, because of reduced surface albedo. The warmed surface amplifies stationary Rossby waves, leading to a deceleration of the subpolar jet. As a consequence, rising motion is enhanced over the land, and compensating subsidence and adiabatic heating occur in the Arctic troposphere, forming the negative NAM. The intensified anticyclonic circulation has played a contributing role in accelerating the sea ice decline observed during the last two decades. The results here provide important information for improving seasonal prediction of summer sea ice cover.

Nitta T., 1987: Convective activities in the tropical western Pacific and their impact on the Northern Hemisphere summer circulation.J. Meteor. Soc. Japan,65,373-390, https://doi.org/10.2151/jmsj1965.65.3_373.

10.1175/1520-0469(1987)044<1554:TAOPVT>2.0.CO;2

e2ef16e7dae890eb1752e3cd22affb10

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F10013126166%2F

https://www.jstage.jst.go.jp/article/jmsj1965/65/3/65_3_373/_articleInterannual and intraseasonal variations of convective activities in the tropical western Pacific during summer and their impact on the Northern Hemisphere circulation are investigated by using satellite cloud amount, sea surface temperature (SST) and geopotential data for 7 years (1978-1984). During summers when SST in the tropical western Pacific is about 1.0ºC warmer than normal, active convection regions consisting of a number of typhoons and tropical depressions are shifted northeastward from the normal position near Philippines to the subtropical western Pacific around 20ºN and cloud amounts both in the middle latitudes and in the equatorial regions are greatly suppressed. A high pressure anomaly with little vertical tilt predominates in middle latitudes extending from East China, through Japan Islands to North Pacific during these summers. Analyses of 5-day mean cloud amount reveal that the convective activity is largely modulated by the intraseasonal variations (ISV). The amplitude of ISV of convective activity in the Philippine Sea around 15ºN-20ºN is more intensified in warm SST summers than in cold SST summers resulting in stronger season mean convective activities in the former than in the latter. Correlation computations between 5-day mean tropical cloud amount and 500mb geopotential height show that there exist wave trains of geopotential height emanating from the heat source region near Philippines to North America. Daily analyses of geopotential height indicate that these wave trains appear to be generated when convective activities in the Philippine Sea become intense and that the amplification occurs downstream from the western Pacific to the west coast of North America taking about 5 days. It is concluded that Rossby waves are generated by the tropical heat source associated with ISV, and high pressure anomalies over East Asia and Northwest Pacific during warm SST summers can be understood as the results of frequent occurrence of Rossby wave generation.

Nitta T., Z.-Z. Hu, 1996: Summer climate variability in China and its association with 500 hPa height and tropical convection.J. Meteor. Soc. Japan,74,425-445, https://doi.org/10.2151/jmsj1965.74.4_425.

10.1175/1520-0469(1996)053<2283:OTFOLI>2.0.CO;2

89b69c2c64c12a09c2d165ea0548b543

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F10013127230%2F

https://www.jstage.jst.go.jp/article/jmsj1965/74/4/74_4_425/_articleThis paper is concernd with interannual and interdecadal variabilities of summer rainfall and temperature patterns in China and their association with 500 hPa height in the Northern Hemisphere (NH), tropical convective activities and global sea surface temperature anomaly (SSTA). The temporal evolutions and spatial structures of interannual variation of summer (JJA) rainfall and temperature from 1951 to 1994 over China are revealed through EOF analysis. The spatial pattern of EOF1 for rainfall (EOF1.R) is dominated by a maximum over the middle-lower reaches of the Yangtze River, and a large negative value region in the middle reach of the Yellow River is also obvious. The spatial pattern of EOF1 for temperature (EOF1.T) reflects coherent variations over most regions of China, and it is dominated by a maximum over the middle-lower reaches of the Yangtze River. Linear increase and decrease trends are found in the time coefficients of EOF1.R and EOF1.T, respectively. The quasi-biennial oscillation (QBO) signal is also strong after the middle of the 1970's in repect of their time coefficients. The coupled patterns of rainfall and temperature are picked up through the singular value decomposition (SVD) analysis. The spatial patterns and their temporal evolutions of SVD1 for rainfall (SVD1.R) and SVD1 for temperature (SVD1.T) are quite similar to those of EOF1.R and EOF1.T. There is an abrupt change in the middle 1970's in the time coefficients of SVD2.R and SVD2.T. The variations of summer rainfall and temperature coupled patterns in China are closely connected with the 500 hPa height anomaly over the Northern Hemisphere (NH). The Pacific-Japan (PJ) and Eurasia (EU) teleconnection patterns play a very important role in the spatial patterns of SVD1.R and SVD1.T, especially in the East Asia monsoon region along the middle-lower reaches of the Yangtze River. The abrupt change of China summer climate in the middle 1970's is related with the intensification and southerly location of the western Pacific subtropical high and also the geopotential height changes over Eurasia and in the regions to the north of the Japan Sea in 1977 or 1978. Correlations between the summer rainfall and temperature coupled patterns and monthly-averaged outgoing longwave radiation (OLR) and high-cloud amount (HCA) data are significant with the PJ teleconnection pattern. There exist positive correlations between the coupled patterns and sea surface temperature anomaly (SSTA) in the North Pacific and the tropical western Pacific. A comparison study shows that there are coherent variations between summer rainfall in the middle-lower reaches of the Yangtze River and in the western part of Japan. It is also demonstrated that there are close correlations between the summer temperature variations in China and in Japan.

Rayner N. A., D. E. Parker, E. B. Horton, C. K. Folland , L. V. Alexand er, D. P. Rowell, E. C. Kent, and A. Kaplan, 2003: Global analyses of sea surface temperature,sea ice, and night marine air temperature since the late Nineteenth Century.J. Geophys. Res.,108,4407, https://doi.org/10.1029/2002JD002670.

10.1029/2002JD002670

0831f099871c89699f00bb6e2586346b

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2002JD002670%2Ffull

http://doi.wiley.com/10.1029/2002JD002670We present the Met Office Hadley Centre's sea ice and sea surface temperature (SST) data set, HadISST1, and the nighttime marine air temperature (NMAT) data set, HadMAT1. HadISST1 replaces the global sea ice and sea surface temperature (GISST) data sets and is a unique combination of monthly globally complete fields of SST and sea ice concentration on a 1º latitude-longitude grid from 1871. The companion HadMAT1 runs monthly from 1856 on a 5º latitude-longitude grid and incorporates new corrections for the effect on NMAT of increasing deck (and hence measurement) heights. HadISST1 and HadMAT1 temperatures are reconstructed using a two-stage reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail. The sea ice fields are made more homogeneous by compensating satellite microwave-based sea ice concentrations for the impact of surface melt effects on retrievals in the Arctic and for algorithm deficiencies in the Antarctic and by making the historical in situ concentrations consistent with the satellite data. SSTs near sea ice are estimated using statistical relationships between SST and sea ice concentration. HadISST1 compares well with other published analyses, capturing trends in global, hemispheric, and regional SST well, containing SST fields with more uniform variance through time and better month-to-month persistence than those in GISST. HadMAT1 is more consistent with SST and with collocated land surface air temperatures than previous NMAT data sets.

Sardeshmukh P. D., B. J. Hoskins, 1988: The generation of global rotational flow by steady idealized tropical divergence. J. Atmos. Sci., 45, 1228-1251, https://doi.org/10.1175/1520-0469(1988)045<1228:TGOGRF>2.0,CO;2.

10.1175/1520-0469(1988)0452.0.CO;2

b2412b73da38526cb734520e966688b9

http%3A%2F%2Fonlinelibrary.wiley.com%2Fresolve%2Freference%2FADS%3Fid%3D1988JAtS...45.1228S

http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%281988%29045%3C1228%3ATGOGRF%3E2.0.CO%3B2Abstract Tropical convective heating is balanced on the large scale by the adiabatic cooling of ascent. The horizontal divergence of the wind above this heating may be viewed as driving the upper tropospheric rotational wind field. A vorticity equation model is used to diagnose this relationship. It is shown that because of the advection of vorticity by the divergent component of the flow, the Rossby wave source can be very different from the simple 抐D source often used. In particular, an equatorial region of divergence situated in easterly winds can lead to a Rossby wave source in the subtropical westerlies where it is extremely effective. This part of the source can be relatively insensitive to the longitudinal position of the equatorial divergence. A divergence field which is asymmetric about the equator can lead to a quite symmetric Rossby wave source. For a steady frictionless flow the Rossby wave source averaged over regions within closed streamfunction or absolute vorticity contours is, under cert...

Screen J. A., 2013: Influence of Arctic sea ice on European summer precipitation,Environmental Research Letters,8,044015, https://doi.org/10.1088/1748-9326/8/4/044015.

10.1088/1748-9326/8/4/044015

8c1f32f7ca34bd27f63b35abea55aec9

http%3A%2F%2Fwww.ingentaconnect.com%2Fsearch%2Farticle%3Foption1%3Dtka%26amp%3Bvalue1%3DEuropean%2Bseas%26amp%3BpageSize%3D10%26amp%3Bindex%3D4

http://stacks.iop.org/1748-9326/8/i=4/a=044015?key=crossref.42089eb0cee2159ec299ee960d1840a4

Takaya K., H. Nakamura, 2001: A formulation of a phase-independent wave-activity flux for stationary and migratory quasigeostrophic eddies on a zonally varying basic flow. J. Atmos. Sci., 58, 608-627, https://doi.org/10.1175/1520-0469(2001)058<0608:AFOAPI>2.0,CO;2.

10.1175/1520-0469(2001)058<0608:AFOAPI>2.0.CO;2

cd8c40c8181e2ef17726a6d7ec840f85

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2001JAtS...58..608T

http://adsabs.harvard.edu/abs/2001JAtS...58..608TA new formulation of an approximate conservation relation of wave-activity pseudomomentum is derived, which is applicable for either stationary or migratory quasigeostrophic (QG) eddies on a zonally varying basic flow. The authors utilize a combination of a quantity A that is proportional to wave enstrophy and another quantity that is proportional to wave energy. Both A and are approximately related to the wave-activity pseudomomentum. It is shown for QG eddies on a slowly varying, unforced nonzonal flow that a particular linear combination of A and , namely, M (A + )/2, is independent of the wave phase, even if unaveraged, in the limit of a small-amplitude plane wave. In the same limit, a flux of M is also free from an oscillatory component on a scale of one-half wavelength even without any averaging. It is shown that M is conserved under steady, unforced, and nondissipative conditions and the flux of M is parallel to the local three-dimensional group velocity in the WKB limit. The authors' conservation relation based on a straightforward derivation is a generalization of that for stationary Rossby waves on a zonally uniform basic flow as derived by Plumb and others.A dynamical interpretation is presented for each term of such a phase-independent flux of the authors or Plumb. Terms that consist of eddy heat and momentum fluxes are shown to represent systematic upstream transport of the mean-flow westerly momentum by a propagating wave packet, whereas other terms proportional to eddy streamfunction anomalies are shown to represent an ageostrophic flux of geopotential in the direction of the local group velocity. In such a flux, these two dynamical processes acting most strongly on the node lines and ridge/trough lines of the eddy streamfunction field, respectively, are appropriately combined to eliminate its phase dependency. The authors also derive generalized three-dimensional transformed Eulerian-mean equations with the residual circulation and eddy forcing both expressed in phase-independent forms.The flux may not be particularly suited for evaluating the exact local budget of M, because of several assumptions imposed in the derivation. Nevertheless, these assumptions seem qualitatively valid in the assessment based on observed and simulated data. The wave-activity flux is a useful diagnostic tool for illustrating a`snapshot' of a propagating packet of stationary or migratory QG wave disturbances and thereby for inferring where the packet is emitted and absorbed, as verified in several applications to the data. It may also be useful for routine climate diagnoses in an operational center.

Tian S.-F., T. Yasunari, 1992: Time and space structure of interannual variations in summer rainfall over China.J. Meteor. Soc. Japan,70,585-596, https://doi.org/10.2151/jmsj1965.70.1B_585.

10.2151/jmsj1965.70.1B_585

5899a2dd11d2b0e561da3d3978e6d962

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F40000634892

https://www.jstage.jst.go.jp/article/jmsj1965/70/1B/70_1B_585/_articlereact-text: 526 Numerical weather prediction is considered as an initial/boundary value problem: given an estimate of the present state of the atmosphere (initial conditions), and appropriate surface and lateral boundary conditions, an atmospheric model is able to simulate the future state of the atmosphere. Therefore, the more accurate the estimate of the initial conditions, the better the quality of the... /react-text react-text: 527 /react-text [Show full abstract]

Wang H. J., S. P. He, 2015: The North China/Northeastern Asia severe summer drought in 2014.J. Climate,28,6667-6681, https://doi.org/10.1175/JCLI-D-15-0202.1.

10.1175/JCLI-D-15-0202.1

b073ea7a25f753b91ff51ee7281f9c48

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2015JCli...28.6667W

http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0202.1ABSTRACT In summer 2014, north China and large areas of northeastern Asia (NCNEA) suffered from the most severe drought of the past 60 years. This study indicates that the East Asian summer precipitation in 2014 exhibited a tripole anomaly, with severe negative anomalies in NCNEA, strong positive anomalies in south China, South Korea, and Japan, and intense negative anomalies in the western North Pacific. Along with the severe tripole precipitation anomalies, there were strong intensities of the Silk Road pattern, the Pacific-Japan pattern, and the Eurasian teleconnection pattern, which were responsible for the strong precipitation anomaly in 2014 through changes to the western Pacific subtropical high (WPSH) and the East Asian trough. Further analysis indicates that the sea surface temperature (SST) in the North Pacific was nearly the warmest in the past 60 years and, together with the strong SST warming in the warm pool region, thus caused the strong Pacific-Japan teleconnection pattern, southward positioning of the WPSH, and weakened East Asian summer monsoon. Additionally, the summertime sea ice cover in the Arctic Ocean was anomalous, resulting in high SST in the Laptev-Kara Sea and, hence, triggering a strong Eurasian teleconnection pattern and contributing to the severe drought of NCNEA. Furthermore, the intense warming over the European Continent and Caspian Sea favored the Silk Road pattern, also contributing to the southward positioning of the WPSH and the NCNEA drought. The NCNEA severe drought was therefore the joint result of Pacific SST anomalies, Arctic sea ice anomalies, and warming over the European Continent and Caspian Sea.

Wang H. J., H. P. Chen, 2012: Climate control for southeastern China moisture and precipitation: Indian or East Asian monsoon? J,Geophys. Res.,117,D12109, https://doi.org/10.1029/2012JD017734.

10.1029/2012JD017734

00f6fdf0394cbe73e16f92c88c161251

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2012JD017734%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2012JD017734/fullIn this study, the water vapor sources for the precipitation processes in southeastern China (SECN) during 1981-2010 were investigated using atmospheric reanalysis data. We also studied the factors influencing the summer atmospheric moisture over SECN. These two issues are all closely related to the climate signals recorded in stalagmites recovered from caves in SECN. Result supports that the atmospheric water vapor over SECN during the whole summer time is primarily transported from the Indian Ocean. However, the vertically integrated water vapor content throughout the year in SECN has two main sources: the Indian Ocean and the tropical western Pacific. In addition, the water vapor transport for the precipitation processes in SECN has complex vertical structure. At approximately 700 hPa to 500 hPa, part of the water vapor for the precipitation in SECN comes from the Arab-Caspian region. Finally, the water vapor content over SECN is regulated primarily by both the Indian and East Asian monsoons. Further analysis indicated that the variability of the East Asian summer monsoon is substantially regulated by the western Pacific subtropical high, the Eurasia-Atlantic thermal conditions, as well as the large-scale Eurasia-Atlantic atmospheric circulation. Therefore, the SECN Cave proxies can record the signals from faraway middle and high latitude Eurasia-Atlantic climate, besides the regional East Asian monsoon and remote Indian monsoon.

Wang T., H. J. Wang, O. H. Otter濮橈拷, Y. Q. Gao, L. L. Suo, T. Furevik, and L. Yu, 2013: Anthropogenic agent implicated as a prime driver of shift in precipitation in eastern China in the late 1970s.Atmospheric Chemistry and Physics,13,12433-12450, .http://doi.org/10.5194/acp-13-12433-2013

10.5194/acp-13-12433-2013

211d47d45a58674be11484110cfae655

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2013acp....1312433w

http://www.atmos-chem-phys.net/13/12433/2013/Observation shows that eastern China experienced an interdecadal shift in the summer precipitation during the second half of the 20th century. The summer precipitation increased in the middle and lower reaches of the Yangtze River valley, whereas it decreased in northern China. Here we use a coupled ocean-atmosphere general circulation model and multi-ensemble simulations to show that the interdecadal shift is mainly caused by the anthropogenic forcing. The rapidly increasing greenhouse gases induce a notable Indian Ocean warming, causing a westward shift of the western Pacific subtropical high (WPSH) and a southward displacement of the East Asia westerly jet (EAJ) on an interdecadal timescale, leading to more precipitation in Yangtze River valley. At the same time the surface cooling effects from the stronger convection, higher precipitation and rapidly increasing anthropogenic aerosols contribute to a reduced summer land-sea thermal contrast. Due to the changes in the WPSH, the EAJ and the land-sea thermal contrast, the East Asian summer monsoon weakened resulting in drought in northern China. Consequently, an anomalous precipitation pattern started to emerge over eastern China in the late 1970s. According to the model, the natural forcing played an opposite role in regulating the changes in WPSH and EAJ, and postponed the anthropogenically forced climate changes in eastern China. The Indian Ocean sea surface temperature is crucial to the response, and acts as a bridge to link the external forcings and East Asian summer climate together on a decadal and longer timescales. Our results further highlight the dominant roles of anthropogenic forcing agents in shaping interdecadal changes of the East Asian climate during the second half of the 20th century.

Weng H. Y., K.-M. Lau, and Y. K. Xue, 1999: Multi-scale summer rainfall variability over China and its long-term link to global sea surface temperature variability.J. Meteor. Soc. Japan,77,845-857, https://doi.org/10.2151/jmsj1965.77.4_845.

10.1175/1520-0469(1999)056<2728:OTFSIT>2.0.CO;2

dbace0ebcb5bb0802aaf81e6adde35ca

http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F10013127193

https://www.jstage.jst.go.jp/article/jmsj1965/77/4/77_4_845/_articleMulti-scale summer (Jun-Aug) rainfall variability over China and its long-term link to global sea surface temperature (SST) variability are studied for the period of 1955-1997. First, the dominant spatial and temporal patterns of the observed rainfall anomaly are studied by empirical orthogonal function (EOF) analysis. By a wavelet transform, interannual and decadal-interdecadal variabilities as well as a trend are found, with different dominance, in the first two EOF modes. EOF1 shows a sudden shift in rainfall anomaly over China in the late 1970s, representing overall wetter conditions in central China and drier conditions in northern and southern China in the 1980s than the conditions in the 1960s. This sudden shift is associated with a quasi-in-phase reinforcement between bidecadal and quadridecadal variabilities. EOF2 represents an increasing trend in the rainfall anomaly in broad central and southern China, especially in the Yangtze River valley, without an apparent shift in the late 1970s. The lack of such a shift is associated with an out-of-phase partial cancellation between a bidecadal cycle and the trend around that time. Second, to understand the long-term rainfall variability that is linked to global SST variability, the singular value decomposition (SVD) analysis for the two fields is carried out. SVD1 links drought conditions in northern China and flood conditions in central China to an El Niño-like SST anomaly distribution. This mode shows both an apparent trend and a regime shift in the late 1970s, which do not coexist in the rainfall EOF modes. SVD2 links the rainfall anomaly in the area between the Yangtze River and the Yellow River and the opposite anomaly in southern China to a wave-like SST anomaly distribution in the eastern Pacific from tropics to extratropics. SVD3 links the rainfall anomaly in the Yangtze River valley to the SST anomaly in the western Pacific centered near 20ºN 140ºE. The rainfall variability in different areas of China that can be attributed to SST effects results from the interplay of the SVD modes. The most significant links found from SVD analysis are verified by cross-correlation functions. A scenario for a long-term link on the trend scale between the rainfall over China and global SST variabilities, through the associated large-scale circulation, is presented.

Wu B. Y., R. H. Zhang, B. Wang, and R. D'Arrigo, 2009: On the association between spring Arctic sea ice concentration and Chinese summer rainfall,Geophys. Res. Lett.,36,L09501, https://doi.org/10.1029/2009GL037299.

10.1029/2009GL037299

942eda0778ebc3ab2750515e08040092

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs00376-009-9009-3

http://link.springer.com/article/10.1007/s00376-009-9009-3In our previous study, a statistical linkage between the spring Arctic sea ice concentration (SIC) and the succeeding Chinese summer rainfall during the period 19682005 was identified. This linkage is demonstrated by the leading singular value decomposition (SVD) that accounts for 19% of the co-variance. Both spring SIC and Chinese summer rainfall exhibit a coherent interannual variability and two apparent interdecadal variations that occurred in the late 1970s and the early 1990s. The combined impacts of both spring Arctic SIC and Eurasian snow cover on the summer Eurasian wave train may explain their statistical linkage. In this study, we show that evolution of atmospheric circulation anomalies from spring to summer, to a great extent, may explain the spatial distribution of spring and summer Arctic SIC anomalies, and is dynamically consistent with Chinese summer rainfall anomalies in recent decades. The association between spring Arctic SIC and Chinese summer rainfall on interannual time scales is more important relative to interdecadal time scales. The summer Arctic dipole anomaly may serve as the bridge linking the spring Arctic SIC and Chinese summer rainfall, and their coherent interdecadal variations may reflect the feedback of spring SIC variability on the atmosphere. The summer Arctic dipole anomaly shows a closer relationship with the Chinese summer rainfall relative to the Arctic Oscillation.

Xie S.-P., K. M. Hu, J. Hafner, H. Tokinaga, Y. Du, G. Huang, and T. Sampe, 2009: Indian Ocean capacitor effect on Indo-western Pacific climate during the summer following El Niño.J. Climate,22,730-747, .http://doi.org/10.1175/2008JCLI2544.1

10.1175/2008JCLI2544.1

5ca7332e21ffff9143909ee76fe9bab3

http%3A%2F%2Fwww.cabdirect.org%2Fabstracts%2F20093117314.html

http://journals.ametsoc.org/doi/abs/10.1175/2008JCLI2544.1Significant climate anomalies persist through the summer (June-August) after El Nino dissipates in spring over the equatorial Pacific. They include the tropical Indian Ocean (TIO) sea surface temperature (SST) warming, increased tropical tropospheric temperature, an anomalous anticyclone over the subtropical northwest Pacific, and increased mei-yu-baiu rainfall over East Asia. The cause of these lingering El Nino effects during summer is investigated using observations and an atmospheric general circulation model (GCM). The results herein indicate that the TIO warming acts like a capacitor anchoring atmospheric anomalies over the Indo-western Pacific Oceans. It causes tropospheric temperature to increase by a moist-adiabatic adjustment in deep convection, emanating a baroclinic Kelvin wave into the Pacific. In the northwest Pacific, this equatorial Kelvin wave induces northeasterly surface wind anomalies, and the resultant divergence in the subtropics triggers suppressed convection and the anomalous anticyclone. The GCM results support this Kelvin wave-induced Ekman divergence mechanism. In response to a prescribed SST increase over the TIO, the model simulates the Kelvin wave with low pressure on the equator as well as suppressed convection and the anomalous anticyclone over the subtropical northwest Pacific. An additional experiment further indicates that the north Indian Ocean warming is most important for the Kelvin wave and northwest Pacific anticyclone, a result corroborated by observations. These results have important implications for the predictability of Indo-western Pacific summer climate: the spatial distribution and magnitude of the TIO warming, rather than simply whether there is an El Nino in the preceding winter, affect summer climate anomalies over the Indo-western Pacific and East Asia.

Xu Z. Q., K. Fan, and H. J. Wang, 2016: Role of sea surface temperature anomalies in the tropical Indo-Pacific region in the northeast Asia severe drought in summer 2014: Month-to-month perspective. Climate Dyn., https://doi.org/10.1007/s00382-016-3406-y.

10.1007/s00382-016-3406-y

f514ada3f3d59407ad4e8024a91ee600

http%3A%2F%2Flink.springer.com%2F10.1007%2Fs00382-016-3406-y

http://link.springer.com/10.1007/s00382-016-3406-yAbstract The severe drought over northeast Asia in summer 2014 and the contribution to it by sea surface temperature (SST) anomalies in the tropical Indo-Pacific region were investigated from the month-to-month perspective. The severe drought was accompanied by weak lower-level summer monsoon flow and featured an obvious northward movement during summer. The mid-latitude Asian summer (MAS) pattern and East Asia/Pacific teleconnection (EAP) pattern, induced by the Indian summer monsoon (ISM) and western North Pacific summer monsoon (WNPSM) rainfall anomalies respectively, were two main bridges between the SST anomalies in the tropical Indo-Pacific region and the severe drought. Warming in the Arabian Sea induced reduced rainfall over northeast India and then triggered a negative MAS pattern favoring the severe drought in June 2014. In July 2014, warming in the tropical western North Pacific led to a strong WNPSM and increased rainfall over the Philippine Sea, triggering a positive EAP pattern. The equatorial eastern Pacific and local warming resulted in increased rainfall over the off-equatorial western Pacific and triggered an EAP-like pattern. The EAP pattern and EAP-like pattern contributed to the severe drought in July 2014. A negative Indian Ocean dipole induced an anomalous meridional circulation, and warming in the equatorial eastern Pacific induced an anomalous zonal circulation, in August 2014. The two anomalous cells led to a weak ISM and WNPSM, triggering the negative MAS and EAP patterns responsible for the severe drought. Two possible reasons for the northward movement of the drought were also proposed.

Xue F., J.-J. Zhao, 2017: Intraseasonal variation of the East Asian summer monsoon in La Niña years.Atmospheric and Oceanic Science Letters,10,156-161, 2016. 1254008.https://doi.org/10.1080/16742834.

10.1080/16742834.2016.1254008

79bb64b46b3f8138050fa942054bb3f8

http%3A%2F%2Fkns.cnki.net%2FKCMS%2Fdetail%2Fdetail.aspx%3Ffilename%3Daosl201702007%26dbname%3DCJFD%26dbcode%3DCJFQ

https://www.tandfonline.com/doi/full/10.1080/16742834.2016.1254008

Yu L., 2013: Potential correlation between the decadal East Asian summer monsoon variability and the Pacific decadal oscillation.Atmospheric and Oceanic Science Letters,6,394-397, https://doi.org/10.3878/j.issn.1674-2834.13.0040.

10.1080/16742834.2013.11447114

bb0135e065d65455d98515035a97d6d7

http%3A%2F%2Fkns.cnki.net%2FKCMS%2Fdetail%2Fdetail.aspx%3Ffilename%3Daosl201305030%26dbname%3DCJFD%26dbcode%3DCJFQ

http://www.tandfonline.com/doi/full/10.1080/16742834.2013.11447114

Yu L., T. Furevik, O. H. Otter濮橈拷, and Y. Q. Gao, 2015: Modulation of the Pacific Decadal Oscillation on the summer precipitation over East China: A comparison of observations to 600-years control run of Bergen Climate Model.Climate Dyn.,44,475-494, https://doi.org/10.1007/s00382-014-2141-5.

10.1007/s00382-014-2141-5

94610e85c29b460a2c6696a0555cc478

http%3A%2F%2Flink.springer.com%2F10.1007%2Fs00382-014-2141-5

http://link.springer.com/10.1007/s00382-014-2141-5Observations show that the summer precipitation over East China often goes through decadal variations of opposite sign over North China and the Yangtze River valley (YRV), such as the “southern flood and northern drought” pattern that occurred during the late 1970s–1990s. In this study it is shown that a modulation of the Pacific Decadal Oscillation (PDO) on the summer precipitation pattern over East China during the last century is partly responsible for this characteristic precipitation pattern. During positive PDO phases, the warm winter sea surface temperatures (SSTs) in the eastern subtropical Pacific along the western coast of North American propagate to the tropics in the following summer due to weakened oceanic meridional circulation and the existence of a coupled wind–evaporation–SST feedback mechanism, resulting in a warming in the eastern tropical Pacific Ocean (5°N–20°N, 160°W–120°W) in summer. This in turn causes a zonal anomalous circulation over the subtropical–tropical Pacific Ocean that induces a strengthened western Pacific subtropical high (WPSH) and thus more moisture over the YRV region. The end result of these events is that the summer precipitation is increased over the YRV region while it is decreased over North China. The suggested mechanism is found both in the observations and in a 600-years fully coupled pre-industrial multi-century control simulations with Bergen Climate Model. The intensification of the WPSH due to the warming in the eastern tropical Pacific Ocean was also examined in idealized SSTA-forced AGCM experiments.

Yu R.C., T. J. Zhou, 2007: Seasonality and three-dimensional structure of interdecadal change in the East Asian monsoon.J. Climate,20,5344-5355, http://doi.org/10.1175/2007JCLI1559.1.

10.1175/2007JCLI1559.1

4c86b70a5798b4316f51386783f01c76

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2007JCli...20.5344Y

http://journals.ametsoc.org/doi/abs/10.1175/2007JCLI1559.1A significant interdecadal cooling with vivid seasonality and three-dimensional (3D) structure is first revealed in the upper troposphere and lower stratosphere over East Asia. A robust upper-tropospheric cooling appears in March and has two peaks in April and August, but in June, a moderate uppertropospheric warming interrupts the cooling, while strong cooling occurs in the lower stratosphere. The seasonally dependent upper-tropospheric cooling leads to a clear seasonality of interdecadal changes in the atmospheric general circulation and precipitation against their normal seasonal cycle over East Asia. In March, precipitation over southern China (south of 26°N) has increased in accordance with the strong upper-tropospheric cooling occurring in northeast Asia. In April and May, following the southward extension and intensification of the upper-tropospheric cooling, the normal seasonal march of the monsoon rainband has been interrupted, resulting in a drying band to the south of the Yangtze River valley in late spring. In June, the moderate upper-tropospheric warming and strong lower-stratospheric cooling over northeast Asia has suddenly enhanced the northward migration of the rainband and resulted in an increase of precipitation in the mid–lower reaches of the Yangtze River and farther north. During July and August, the return of upper-tropospheric cooling has weakened the northward progression of southerly monsoon winds, resulting in a mid–lower Yellow River valley (34°–40°N) drought and excessive rain in the Yangtze River valley. The change of surface temperature is well correlated with the change in precipitation, especially in the spring. The surface cooling is generally collocated with excessive rain, while the warming is generally collocated with droughts. Possible causes for the robust interdecadal change are discussed, and stratosphere–troposphere interaction is suggested to play a crucial role in seasonally dependent 3D atmospheric cooling over East Asia.

Zhao P., X. D. Zhang, X. J. Zhou, M. Ikeda, and Y. H. Yin, 2004: The sea ice extent anomaly in the North Pacific and its impact on the East Asian summer monsoon rainfall. J. Climate, 17, 3434-3447, https://doi.org/10.1175/1520-0442(2004)017<3434:TSIEAI>2.0,CO;2.

10.1175/1520-0442(2004)0172.0.CO;2

b61b47b1a73a75d0e1f59d515bc723fe

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2004jcli...17.3434z

http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%282004%29017%3C3434%3ATSIEAI%3E2.0.CO%3B2The relationship between extreme anomalies of the spring sea ice extent over the Bering Sea and the Sea of Okhotsk and rainfall variability in the east Asian summer monsoon was examined through an analysis of observed data and modeling experiments. The results show that reduced sea ice extent leads to an enhanced summer monsoon rainfall in southeastern China. This relationship is well supported by the background atmospheric circulation changes and the stationary wave dynamics. A difference in the 500-hPa geopotential height composed from the NCEP-NCAR reanalysis data and model output between the light and heavy sea ice cases shows an anomalous high in the east Asian summer, which favors the invasion of a cold air mass into southern China and prevents the east Asian summer monsoon from advancing northward. Hence, the mei-yu front and its associated rainfall intensify and stay in southeastern China. The generation of the summer anomalous high and its interseasonal link to the spring sea ice extent anomalies can be accounted for by the stationary wave dynamics and the land surface process. In spring, the decrease in sea ice extent forces eastward-propagating wave activity flux and causes an anomalous high in Europe along with a decrease in precipitation. The decreased soil water content results in a higher land surface temperature and more sensible heat flux in summer, and this strengthens summer stationary wave activities in Europe. The eastward propagation of the wave energy and its intensification in east Asia are responsible for the anomalous high in the east Asian summer. In this process, the European land surface acts as a bridge linking the spring sea ice extent anomalies with the east Asian summer monsoon.