doi:10.1007/s00376-015-5054-2

Barre J., V. H. Peuch, J. L. Atti, L. El Amraoui, W. A. Lahoz, B. Josse, M. Claeyman, P. Nec, 2012: Stratosphere-troposphere ozone exchange from high resolution MLS ozone analyses. Atmospheric Chemistry and Physics, 12( 14), 6129- 6144.10.5194/acp-12-6129-2012

8ea67068808487b6c4b50b564acd285f

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F258564429_Stratosphere-troposphere_ozone_exchange_from_high_resolution_MLS_ozone_analyses

http://www.researchgate.net/publication/258564429_Stratosphere-troposphere_ozone_exchange_from_high_resolution_MLS_ozone_analysesWe assimilate stratospheric ozone profiles from MLS (Microwave Limb Sounder) into the MOCAGE Chemistry Transport Model (CTM) to study Stratosphere-Troposphere Exchange (STE). This study uses two horizontal grid resolutions of 200 and 0.200. The combined impacts of MLS ozone assimilation and high horizontal resolution are illustrated in two case studies

Bethan S., G. Vaughan, and S. J. Reid, 1996: A comparison of ozone and thermal tropopause heights and the impact of tropopause definition on quantifying the ozone content of the troposphere. Quart. J. Roy. Meteor. Soc., 122( 532), 929- 944.10.1002/qj.49712253207

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fqj.49712253207%2Fcitedby

refpaperuri:(97e4689a818df08238f96cfa3b7db44f)

http://onlinelibrary.wiley.com/doi/10.1002/qj.49712253207/citedbyABSTRACT A comparison has been conducted of the height and sharpness of the tropopause as revealed by temperature and ozone profiles. In the study, 628 ECC-type ozonesonde profiles from four stations in northern Europe were used. Two tropopauses were defined for each profile: a thermal tropopause and an ozone tropopause defined in terms of both mixing ratio and vertical gradient of mixing ratio. On average, the ozone tropopause lay 800 m below the thermal. Large differences in tropopause height were associated with indefinite thermal tropopauses which were, in turn, often associated with cyclonic conditions (some corresponding to profiles taken within the stratospheric polar vortex). On almost all profiles the thermal tropopause was the higher of the two, and of the 15 profiles that did not fit this pattern, two-thirds were associated with anticyclonic flow in the upper troposphere. It is also shown that the tropopause definition impacts greatly on the evaluation of the ozone content of the troposphere. Where the thermal tropopause is indefinite in character, on average 27% of the ozone found below the thermal tropopause lies above the ozone tropopause.

Bian J. C., 2009: Recent Advances in the study of atmospheric vertical structures in upper troposphere and lower stratosphere. Advances in Earth Science, 24( 3), 229- 241. (in Chinese)10.1016/S1003-6326(09)60084-4

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http%3A%2F%2Fen.cnki.com.cn%2FArticle_en%2FCJFDTOTAL-DXJZ200903006.htm

http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXJZ200903006.htmThe issues in the atmospheric tropopause structure and its variation are crucial in the study of stratosphere-troposphere exchange and the balance of atmospheric tracers in the upper troposphere and lower stratosphere,and the change of global tropopause height is a significant indicator in the climate change caused by human activity.Therefore,the study of tropopause,particularly the finer structure and key processes,arouses the attention in the world.In this paper,recent advances in the study of a few basic scientific problems on the definitions of tropopause(such as thermal,dynamical,and chemical definitions,and relationships among them),tropopause being a interface or a layer and the role of mixing in the transition between troposphere and stratosphere,and the distribution feature of tropopause inversion layer and its formation,are reviewed,and current problems among them are given some comments.

Bian J. C., A. Gettelman, H. B. Chen, and L. L. Pan, 2007: Validation of satellite ozone profile retrievals using Beijing ozonesonde data. J. Geophys. Res., 112(D6),D06305, doi: 10.1029/2006JD007502.10.1029/2006JD007502

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD007502%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2006JD007502/full[1] Ozonesondes launched from Beijing, China, over a 3 year time period (September 2002 to July 2005) are used to evaluate the performance of ozone profile retrievals in the upper troposphere and lower stratosphere (UTLS) from two new spaceborne instruments, the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua satellite and the Microwave Limb Sounder (MLS) on the NASA Aura satellite. Since the Global Positioning System ozone sensors (GPSO3) used in Beijing ozonesondes are new, comparisons with simultaneously launched Vaisala ECC sensors, and comparisons with an ozonesonde climatology from Sapporo, Japan, are presented. The results show that although the new GPSO3 sensor has a positive bias (about 20-30%) below 200 hPa and a negative bias (about 5-10%) above 60 hPa relative to known sensors, the measured ozone variability is consistent with Vaisala ECC ozonesondes, particularly in the UTLS region. The GPSO3 ozonesonde profiles over Beijing are then used to evaluate coincident ozone profiles from AIRS version 4 retrieval and MLS version 1.5 retrieval. Qualitatively, both satellite data sets can reproduce the gradients and variability of ozone in the UTLS region. Quantitatively, the agreement between the AIRS and ozonesonde ozone profiles is largely within 10% in the UTLS region (from 400 to 70 hPa). The statistical difference between the retrieval and ozonesonde data is minimum in the vicinity of the tropopause. The MLS ozone profiles also show good quality in the UTLS region with the best performance between 147 and 46 hPa.

Birner T., A. Dnbrack, and U. Schumann, 2002: How sharp is the tropopause at midlatitudes? Geophys. Res. Lett.,29(14), 45-1-45-4.10.1029/2002GL015142

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2002GL015142%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2002GL015142/pdf[1] Ten years of high-resolution radiosonde data are contrasted with fifteen years of ECMWF reanalysis (ERA) data to explore the tropopause region above two midlatitude stations (Munich and Stuttgart) in Southern Germany. We present time-averaged vertical profiles of several meteorological parameters relative to the tropopause. A strong mean inversion at the tropopause is evident from the radiosonde profiles with a vertical extension of about 2 km and a temperature increase of about 4 K. The impact of the tropopause definition on the strength of this inversion is discussed as well as the relevance of baroclinic eddies in forming it. The climatological profiles for Munich and Stuttgart do not differ significantly.

Bourqui M. S., 2006: Stratosphere-troposphere exchange from the Lagrangian perspective: A case study and method sensitivities. Atmospheric Chemistry and Physics, 6( 9), 2651- 2670.10.5194/acpd-4-3249-2004

42e7385f58d501dcdf940541611f2c05

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F2704328

http://www.oalib.com/paper/2704328An important part of extra-tropical stratosphere-to-troposphere transport occurs in association with baroclinic wave breaking and cut-off decay at the tropopause. In the last decade many studies have attempted to estimate stratosphere-troposphere exchange (STE) in such synoptic events with various methods, and more recently efforts have been made to inter-compare these methods. These inter-comparisons show large variations between estimates from different methods. This large uncertainty points to a need to thoroughly evaluate such methods, assess the realism of the resulting STE estimates and determine the sensitivities to intrinsic parameters of the methods. The present study focuses on a trajectory-based Lagrangian method which has been applied in the past to climatological studies. This method is applied here to the quantification of STE in the context of a typical baroclinic wave breaking event. The analysis sheds light on (i) the complex three-dimensional temporal and spatial structures that are associated with the rapid inflow of stratospheric air into the troposphere, (ii) the variation of STE mass flux with the choice of the dynamical tropopause definition within 1.5 to 5 PVU, (iii) the sensitivity of the results to resolution, and in particular the minimum spatial resolution of 1070705x1070705 required reasonably capture STE fluxes in this wave breaking event, (iv) the effective removal of spurious exchange events using a threshold residence time larger than 8 h.

Brewer A. W., 1949: Evidence for a world circulation provided by the measurements of helium and water vapour distribution in the stratosphere. Quart. J. Roy. Meteor. Soc., 75( 326), 351- 363.10.1002/qj.49707532603

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fqj.49707532603%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1002/qj.49707532603/pdfABSTRACT Information is now available regarding the vertical distribution of water vapour and helium in the lower stratosphere over southern England. The helium content of the air is found to be remarkably constant up to 20 km but the water content is found to fall very rapidly just above the tropopause, and in the lowest 1 km of the stratosphere the humidity mixing ratio falls through a ratio of 10—1.The helium distribution is not compatible with the view of a quiescent stratosphere free from turbulence or vertical motions. The water-vapour distribution is incompatible with a turbulent stratosphere unless some dynamic process maintains the dryness of the stratosphere. In view of the large wind shear which is normally found just above the tropopause it is unlikely that this region is free from turbulence.The observed distributions can be explained by the existence of a circulation in which air enters the stratosphere at the equator, where it is dried by condensation, travels in the stratosphere to temperate and polar regions, and sinks into the troposphere. The sinking, however, will warm the air unless it is being cooled by radiation and the idea of a stratosphere in radiative equilibrium must be abandoned. The cooling rate must lie between about 0.1 and 1.1 per day but a value near 0.5 per day seems most probable. At the equator the ascending air must be subject to heating by radiation.The circulation is quite reasonable on energy considerations. It is consistent with the existence of lower temperatures in the equatorial stratosphere than in polar and temperate regions, and if the flow can carry ozone from the equator to the poles then it gives a reasonable explanation of the high ozone values observed at high latitudes. The dynamic consequences of the circulation are not considered. It should however be noted that there is considerable difficulty to account for the smallness of the westerly winds in the stratosphere, as the rotation of the earth should convert the slow poleward movement into strong westerly winds.

Chen D., D. R. LÜ, and Z. Y. Chen, 2014: Simulation of the stratosphere-troposphere exchange process in a typical cold vortex over Northeast China. Science China Earth Sciences, 57( 7), 1452- 1463.10.1007/s11430-014-4864-x

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http%3A%2F%2Fwww.cnki.com.cn%2FArticle%2FCJFDTotal-JDXG201407003.htm

http://www.cnki.com.cn/Article/CJFDTotal-JDXG201407003.htmA mesoscale weather research and forecasting (WRF) model was used to simulate a cold vortex that developed over Northeast China during June 1923, 2010. The simulation used high vertical resolution to

Cui H., C. S. Zhao, Y. Qin, X. D. Zheng, Y. G. Zheng, C. Y. Chan, and L. Y. Chan, 2004: An estimation of ozone flux in a stratosphere-troposphere exchange event. Chinese Science Bulletin, 49( 2), 167- 174.10.1360/03wd0244

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http://d.wanfangdata.com.cn/Periodical_kxtb-e200402011.aspxA new method based on mass fluxes and observed ozone profiles was developed to estimate cross-tropopause ozone flux. Using this method, we estimated the cross-tropopause ozone flux in a stratospheric-tropospheric exchange event that occurred over East Asia in March 2001. The result revealed that the ozone flux across the tropopause in this event was an order of magnitude higher than the global and hemispheric average. Compared to the traditional method using a linear relationship between ozone mixing ratio and potential vorticity near the tropopause, the cross-tropopause ozone flux evaluated with ozonesonde data was somewhat higher, although the orders of the two values were the same.

Danielsen E. F., R. S. Hipskind, S. E. Gaines, G. W. Sachse, G. L. Gregory, and G. F. Hill, 1987: Three-dimensional analysis of potential vorticity associated with tropopause folds and observed variations of ozone and carbon monoxide. J. Geophys. Res., 92( D2), 2103- 2111.10.1029/JD092iD02p02103

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2FJD092iD02p02103%2Fpdf

refpaperuri:(c8a82a9ffcd0b21952c5e7a67528eee4)

http://onlinelibrary.wiley.com/doi/10.1029/JD092iD02p02103/pdfABSTRACT The usability and reliability of potential vorticity as a meteorological stratospheric tracer are evaluated. The concept of potential vorticity conservation during transport in which stratospheric and tropospheric air are mixing is tested. Aircraft data collected on April 20, 1984 in the western and southwestern U.S. are analyzed in order to derive potential vorticity data; vertical cross sections of constant-pressure data and temperature and wind speed gradients are examined. The tropopause fold observed during the April 20, 1984 aircraft flights is described. The potential vorticity, ozone mixing ratio, and carbon monoxide mixing ratio are compared; a positive correlation between potential vorticity and the ozone mixing ratio and a negative correlation between the potential vorticity and the carbon monoxide mixing ratio are detected. The data support the concepts of the conservation of potential vorticity, the entrainment and mixing of tropospheric air across the boundaries of the fold, and the applicability of potential vorticity as a stratospheric tracer.

Draxler R. R., G. D. Rolph, 2003: HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model access via NOAA ARL READY website. NOAA Air Resources Laboratory, Silver Spring, MD. [Available online at http://www.arl.noaa.gov/ready/hysplit4.html]

Fishman J., A. E. Wozniak, and J. K. Creilson, 2003: Global distribution of tropospheric ozone from satellite measurements using the empirically corrected tropospheric ozone residual technique: Identification of the regional aspects of air pollution. Atmospheric Chemistry and Physics, 3( 4), 893- 907.10.5194/acp-3-893-2003

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fresolve%2Freference%2FXREF%3Fid%3D10.5194%2Facp-3-893-2003

http://onlinelibrary.wiley.com/resolve/reference/XREF?id=10.5194/acp-3-893-2003Using coincident observations of total ozone from the Total Ozone Mapping Spectrometer (TOMS) and stratospheric ozone profiles from the Solar Backscattered Ultraviolet (SBUV) instruments, detailed maps of tropospheric ozone have been derived on a daily basis over a time period spanning more than two decades. The resultant climatological seasonal depictions of the tropospheric ozone residual (TOR) show much more detail than an earlier analysis that had used coincident TOMS and Stratospheric Aerosol and Gas Experiment (SAGE) ozone profiles, although there are many similarities between the TOMS/SAGE TOR and the TOMS/SBUV TOR climatologies. In particular, both TOR seasonal depictions show large enhancements in the southern tropics and subtropics in austral spring and at northern temperate latitudes during the summer. The much greater detail in this new data set clearly defines the regional aspect of tropospheric ozone pollution in northeastern India, eastern United States, eastern China, and west and southern Africa. Being able to define monthly climatologies for each year of the data record provides enough temporal resolution to illustrate significant interannual variability in some of these regions.

Ganguly N. D., C. Tzanis, 2011: Study of Stratosphere-troposphere exchange events of ozone in India and Greece using ozonesonde ascents. Meteorological Applications, 18( 4), 467- 474.10.1002/met.241

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fmet.241%2Ffull

http://onlinelibrary.wiley.com/doi/10.1002/met.241/fullAbstract Top of page Abstract 1.Introduction 2.Measurement sites, data and analysis 3.Discussion of results 4.A case study of STE of ozone over Athens, Greece (38, 24) 5.Conclusions Acknowledgements References Stratosphere-troposphere Exchange (STE) is an important factor controlling the budget of ozone in the upper troposphere and lower stratosphere. Studies of STE events in India are so far restricted to co-ordinated campaigns, and measurements over longer periods are relatively scarce. In the light of this observation, this paper aims to identify the Indian latitudes most likely to be affected by STE, the frequency of occurrence of shallow and deep STE events, the depth up to which the ozone from the stratosphere descends into the troposphere during STE events and the resultant trend of ozone in the troposphere under the possible influence of STE over the 24 years from 1982 to 2006. In addition, a case study of the STE of ozone, which occurred during a cut-off low event at Athens, Greece, is presented in order to understand the parameters that may contribute to the evolution of these events. It is concluded that STE plays a minor role in the Indian tropospheric ozone budget. On the whole, the occurrence of STE events in India is found to increase with increase in latitude and occur more frequently during winter followed by summer. The occurrence of deep STE is higher at high latitudes while the occurrence of shallow STE is higher at low latitudes. Copyright 2011 Royal Meteorological Society

Gettelman A., P. Hoor, L. L. Pan, W. J. Rand el, M. I. Hegglin, and T. Birner, 2011: The extratropical upper troposphere and lower stratosphere. Reviews of Geophysics,49(3), doi: 10.1029/2011RG000355.10.1029/2011RG000355

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2011RG000355%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2011RG000355/full[1] The extratropical upper troposphere and lower stratosphere (Ex-UTLS) is a transition region between the stratosphere and the troposphere. The Ex-UTLS includes the tropopause, a strong static stability gradient and dynamic barrier to transport. The barrier is reflected in tracer profiles. This region exhibits complex dynamical, radiative, and chemical characteristics that place stringent spatial and temporal requirements on observing and modeling systems. The Ex-UTLS couples the stratosphere to the troposphere through chemical constituent transport (of, e.g., ozone), by dynamically linking the stratospheric circulation with tropospheric wave patterns, and via radiative processes tied to optically thick clouds and clear-sky gradients of radiatively active gases. A comprehensive picture of the Ex-UTLS is presented that brings together different definitions of the tropopause, focusing on observed dynamical and chemical structure and their coupling. This integral view recognizes that thermal gradients and dynamic barriers are necessarily linked, that these barriers inhibit mixing and give rise to specific trace gas distributions, and that there are radiative feedbacks that help maintain this structure. The impacts of 21st century anthropogenic changes to the atmosphere due to ozone recovery and climate change will be felt in the Ex-UTLS, and recent simulations of these effects are summarized and placed in context.

Gimeno L., R. M. Trigo, P. Ribera, and J. A. Garc, 2007: Editorial: Special issue on cut-off low systems (COL). Meteor. Atmos. Phys., 96( 1-2), 1- 2.10.1007/s00703-006-0216-5

8c65c2fbec2fe3776d42709ce05638bb

http%3A%2F%2Fonlinelibrary.wiley.com%2Fresolve%2Freference%2FXREF%3Fid%3D10.1007%2Fs00703-006-0216-5

http://onlinelibrary.wiley.com/resolve/reference/XREF?id=10.1007/s00703-006-0216-5The intense, Ion-g-spell and synoptic scale fog over north India has been studied using Very High Resolution Radiometer (V.H.R.R.) visible imageries of INSAT-1D and Kalpana Geo-Stationary satellites. The intensity, coverage and characteristics of fog seen in satellite imageries are found to be in conformity with the g round-based surface meteorological observations. The Unusually long spell fog formations have been explained using rnaximurn temperature and relative humidity anomalies of I.G.I Airport, New Delhi, Amousi Airport, Lucknow Babatpur Airport, Varanasi and Rajasansi Airport, Amritsar. Atmospheric stability of very high order was seen in the lower part of the atmosphere at Delhi creating favourable condition for the formation of intense and long-spell fog. The relation between Wetness Index derived based on Basist study (1998) using 19, 37 and 85 GHz frequency channels of Special Sensor Microwave/Imager (SSM/I) onboard Defense Meteorological Satellite Programme (DMSP) satellite and fog duration were studied.

Gouget H., G. Vaughan, A. Marenco, and H. G. J. Smit, 2000: Decay of a cut-off low and contribution to stratosphere-troposphere exchange. Quart. J. Roy. Meteor. Soc., 126( 564), 1117- 1141.10.1002/qj.49712656414

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fqj.49712656414%2Ffull

refpaperuri:(054158e3543959c5eaefd07023464457)

http://onlinelibrary.wiley.com/doi/10.1002/qj.49712656414/fullAbstract We present a case study of the decay of a cut-off low over north-west Europe in June 1996, to establish how the stratospheric air initially contained within it was transferred to the troposphere. Two mechanisms for stratosphere-troposphere exchange are examined: direct convective erosion of the base of the low, and filamentation of the outer layers of the low along the flank of the polar jet stream. The approach taken relies on a combination of in-situ ozone and humidity measurements by MOZAIC (Measurement of Ozone and water vapour by Airbus In-service aircraft) aircraft and ozonesondes, and the European Centre for Medium-Range Weather Forecasts analyses. MOZAIC ozone is used to choose two analyses eight days apart at the genesis (14 June 1996) and decay (22 June 1996) of the low which have a consistent ozone/potential-vorticity relationship. Trajectories (both isentropic and three dimensional (3D)) between these two analyses reveal a consistent pattern; at the base of the low (310 K, 450 mb) all the trajectories attain tropospheric PV values whereas, at 320 K, those trajectories that leave the low experience a decrease in PV and those that do not leave the low retain their initial PV. We propose that air parcels leaving the low were stretched into thin filaments along the flank of the jet stream, which made them vulnerable to 3D mixing. A MOZAIC flight on 21 June 1996 provides direct evidence for this process. Up to 22 June 1996 (by which time the low had lost its closed circulation) the satellite images showed very little convection beneath the corresponding PV anomaly. Mixing was only effective at the very base of the stratospheric air at 310 K. On 22 June the remaining remnant of high PV was advected into a region of deep convection over central and eastern Europe, mixing the remaining stratospheric air into the troposphere. Of the initial mass of 10 15 kg of stratospheric air contained in the low, 6 × 10 14 kg was stripped into filaments along the jet and 4 × 10 14 kg remained to be mixed by convection during the period 22–23 June 1996.

Holton J. R., 1990: On the global exchange of mass between the stratosphere and troposphere. J. Atmos. Sci., 47( 3), 392- 395.10.1175/1520-0469(1990)0472.0.CO;2

497931422c5794d5e40c7fdd19f590a7

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F23838871_On_the_global_exchange_of_mass_between_the_stratosphere_and_troposphere

http://www.researchgate.net/publication/23838871_On_the_global_exchange_of_mass_between_the_stratosphere_and_troposphereAbstract Seasonal mean downward mass fluxes across the 100 mb level in the extratropics of both hemispheres are computed using the meridionally integrated residual vertical circulation as determined from the transformed Eulerian mean equations. The eddy momentum and heat flux data required for the calculation are taken from Oort's 15-year climatology. Upward mass flux from the troposphere to the stratosphere in the tropics is computed from mass continuity. The flux is a maximum during Northern Hemisphere winter and a minimum during Northern Hemisphere summer. The computed fluxes imply a 2.5 year turnover time for the global atmospheric layer above 100 mb.

Homeyer C. R., K. P. Bowman, and L. L. Pan, 2010: Extratropical tropopause transition layer characteristics from high-resolution sounding data. J. Geophys. Res.,115(D13), doi: 10.1029/2009JD013664.10.1029/2009JD013664

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2009JD013664%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2009JD013664/pdfAccurate determination of the tropopause is important for applications such as dynamical analysis and forecasting, radiative transfer calculations, and the diagnosis of chemical transport in the atmosphere. In this study, we examine how well the extratropical tropopause is determined in the National Centers for Environmental Prediction (NCEP) high-resolution Global Forecast System (GFS) model analysis over the continental United States using high-resolution aircraft and radiosonde data. The GFS analyses and sounding data compare well, with RMS differences of approximately 600 m, which is comparable to the vertical resolution of the model. The GFS tropopause is a good proxy in areas without in situ observations, but near the subtropical jet the GFS analysis often mistakenly identifies the secondary rather than the primary tropopause. We also explore an alternative method to identify the tropopause by fitting a smoothed step-function to the static stability profile. This new approach provides a measure of the depth of the troposphere-stratosphere transition and facilitates the study of the dynamical behavior of the tropopause region. In particular, using the transition depth, we are able to identify the statistical behavior of temperature in profiles with deep or shallow tropopause transition layers.

Hoskins B. J., M. E. McIntyre, and A. W. Robertson, 1985: On the use and significance of isentropic potential vorticity maps. Quart. J. Roy.Meteor. Soc., 111( 470), 877- 946.10.1002/qj.49711147002

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fqj.49711147002%2Fcitedby

http://onlinelibrary.wiley.com/doi/10.1002/qj.49711147002/citedbyAbstract The two main principles underlying the use of isentropic maps of potential vorticity to represent dynamical processes in the atmosphere are reviewed, including the extension of those principles to take the lower boundary condition into account. the first is the familiar Lagrangian conservation principle, for potential vorticity (PV) and potential temperature, which holds approximately when advective processes dominate frictional and diabatic ones. the second is the principle of ‘invertibility’ of the PV distribution, which holds whether or not diabatic and frictional processes are important. the invertibility principle states that if the total mass under each isentropic surface is specified, then a knowledge of the global distribution of PV on each isentropic surface and of potential temperature at the lower boundary (which within certain limitations can be considered to be part of the PV distribution) is sufficient to deduce, diagnostically, all the other dynamical fields, such as winds, temperatures, geopotential heights, static stabilities, and vertical velocities, under a suitable balance condition. the statement that vertical velocities can be deduced is related to the well-known omega equation principle, and depends on having sufficient information about diabatic and frictional processes. Quasi-geostrophic, semigeostrophic, and ‘nonlinear normal mode initialization’ realizations of the balance condition are discussed. an important constraint on the mass-weighted integral of PV over a material volume and on its possible diabatic and frictional change is noted. Some basic examples are given, both from operational weather analyses and from idealized theoretical models, to illustrate the insights that can be gained from this approach and to indicate its relation to classical synoptic and air-mass concepts. Included are discussions of (a) the structure, origin and persistence of cutoff cyclones and blocking anticyclones, (b) the physical mechanisms of Rossby wave propagation, baroclinic instability, and barotropic instability, and (c) the spatially and temporally nonuniform way in which such waves and instabilities may become strongly nonlinear, as in an occluding cyclone or in the formation of an upper air shear line. Connections with principles derived from synoptic experience are indicated, such as the ‘PVA rule’ concerning positive vorticity advection on upper air charts, and the role of disturbances of upper air origin, in combination with low-level warm advection, in triggering latent heat release to produce explosive cyclonic development. In all cases it is found that time sequences of isentropic potential vorticity and surface potential temperature charts—which succinctly summarize the combined effects of vorticity advection, thermal advection, and vertical motion without requiring explicit knowledge of the vertical motion field—lead to a very clear and complete picture of the dynamics. This picture is remarkably simple in many cases of real meteorological interest. It involves, in principle, no sacrifices in quantitative accuracy beyond what is inherent in the concept of balance, as used for instance in the initialization of numerical weather forecasts.

Hu K. X., R. Y. Lu, and D. H. Wang, 2010: Seasonal climatology of cut-off lows and associated precipitation patterns over Northeast China. Meteor. Atmos. Phys., 106( 1-2), 37- 48.10.1007/s00703-009-0049-0

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http://link.springer.com/article/10.1007/s00703-009-0049-0Cut-off lows (COLs) are significantly associated with many convective events and anomalous regional climate in the Northeast China. By using 49-year NCEP/NCAR reanalysis data, COL events are detected and tracked by an objective and automatic method based on synoptic concept model. Based on this dataset and daily rain-gauge records in Northeast China during 1979-2005, seasonal climatology of COLs and associated precipitation patterns over Northeast China are investigated. Most COLs have a short lifetime of less than a week and have a spatial size ranging from 500 to 1,000m, with slight seasonal differences. Temporal variation of COL occurrence exhibits a seasonal cycle, with a peak in summer, and considerable interannual variability. The COLs tend to occur more frequently over the northern Northeast China Plain, and the center for maximum frequency shows a zonal oscillation, with an extension to continent in summer and a shift to western North Pacific coast in winter. Most COLs form to the east of Lake Baikal and decay over the western North Pacific coast. COLs are apt to move along east or southeast passages around the year, and tracks are relatively more complicated in warm seasons. About a quarter of annual mean precipitation over Northeast China is associated with COLs. Moreover, COL-associated precipitation contributes greatly to total precipitation in northern and northwestern parts of Northeast China, and the ratios of COL contribution are stronger during spring and autumn than in summer.

IPCC, 1996: Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change,section 2. Climate Change 1995-The Science of Climate Change, J. T. Houghton et al., Eds., Cambridge University Press, 572 pp.

Kentarchos A. S., T. D. Davies, 1998: A climatology of cut-off lows at 200 hPa in the Northern Hemisphere, 1990-1994. International Journal of Climatology, 18( 4), 379- 390.10.1002/(SICI)1097-0088(19980330)18:43.0.CO;2-F

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http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0088(19980330)18:4<379::AID-JOC257>3.0.CO;2-F/fullAbstract A statistical study of the size, temporal and spatial distribution of cut-off low (COL) systems on the 200 hPa pressure surface has been conducted for the Northern Hemisphere. The 200 hPa surface is of relevance for stratosphere roposphere exchange processes. The study covered a 5-year period and recorded information (duration, size, position, movement) for all COLs that lasted for 2 days or more. Cut-off lows form more often in summer than winter and in preferred geographical regions. The majority of COLs lasted 2 3 days and very few lasted more than 10 days. Cut-off lows were found over a wide range of sizes, but the majority were between 200 and 1200 km (max diameter in latitude). Approximately 50% of the COLs that lasted more than 3 days moved considerable (>600 km) distances. Although their motion was, as a rule, rather irregular, it was seen that COL systems would characteristically move northwards, or eastwards orthwards as they began to decay. Finally, there was some degree of interannual variability in COL distribution. 08 1998 Royal Meteorological Society

Kim J. H., H. Lee, 2010: What causes the springtime tropospheric ozone maximum over Northeast Asia? Adv. Atmos. Sci.,27(3), 543-551, doi: 10.1007/s00376-009-9098-z.10.1007/s00376-009-9098-z

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http://d.wanfangdata.com.cn/Periodical_dqkxjz-e201003007.aspxScientists have long debated the relative importance of tropospheric photochemical production versus stratospheric influx as causes of the springtime tropospheric ozone maximum over northern mid-latitudes. This paper investigates whether or not stratospheric intrusion and photochemistry play a significant role in the springtime ozone maximum over Northeast Asia, where ozone measurements are sparse. We examine how tropospheric ozone seasonalities over Naha (26N, 128E), Kagoshima (31N, 131E), and Pohang (36N, 129E), which are located on the same meridional line, are related to the timing and location of the jet stream. The ozone seasonality shows a gradual increase from January to the maximum ozone month, which corresponds to April at Naha, May at Kagoshima, and June at Pohang. In order to examine the occurrence of stratospheric intrusion, we analyze a correlation between jet stream activity and tropospheric ozone seasonality. From these analyses, we did not find any favorable evidence supporting the hypothesis that the springtime enhancement may result from stratospheric intrusion. According to trajectory analysis for vertical and horizontal origins of the airmass, a gradual increasing tendency in ozone amounts from January until the onset of monsoon was similar to the increasing ozone formation tendency from winter to spring over mainland China, which has been observed during the build-up of tropospheric ozone over Central Europe in the winter-spring transition period due to photochemistry. Overall, the analyses suggest that photochemistry is the most important contributor to observed ozone seasonality over Northeast Asia.

Komhyr W. D., R. A. Barnes, G. B. Brothers, J. A. Lathrop, and D. P. Opperman, 1995: Electrochemical concentration cell ozonesonde performance evaluation during STOIC 1989. J. Geophys. Res., 100( D5), 9231- 9244.10.1029/94JD02175

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http://onlinelibrary.wiley.com/doi/10.1029/94JD02175/citedbyABSTRACT Electrochemical concentration cell (ECC) ozonesondes flown by NOAA and NASA Wallops Flight Facility (WFF) personnel during the Stratospheric Ozone Intercomparison Campaign (STOIC) conducted at the Jet Propulsion Laboratory's Table Mountain Facility, Wrightwood, California, July 21 to August 1, 1989, exhibited highly similar ozone measurement precisions and accuracies even though considerably different methods were used by the two research groups in preparing the instruments for use and in calibrating the instruments. The Table Mountain data as well as data obtained in the past showed the precisions to range from about +/-3 to +/-12% in the troposphere, remain relatively constant at +/-3% in the stratosphere to 10 mbar, then decrease to about +/-10% at 4-mbar pressure altitude. Corresponding ozone measurement accuracies for individual ozonesonde soundings were estimated to be about +/-6% near the ground, decrease to -7 to 17% in the high troposphere where ozone concentrations are low, increase to about +/-5% in the low stratosphere and remain so to an altitude of about 10 mbar (~32 km), then decrease to -14 to 6% at 4 mbar (~38 km) where ozone concentrations are again low. Stratospheric ozone measurements were also made during STOIC with ground-based lidars and a microwave radiometer that will be used for ozone measurements in the future at sites of the Network for the Detection of Stratospheric Change (NDSC). The ECC ozonesonde observations provided useful comparison data for evaluating the performance of the lidar and microwave instruments.

Kuang S., M. J. Newchurch, J. Burris, L. H. Wang, K. Knupp, and G. Y. Huang, 2012: Stratosphere-to-troposphere transport revealed by ground-based lidar and ozonesonde at a midlatitude site. J. Geophys. Res.: Atmospheres, 117(D18),D18305, doi: 10.1029/2012JD017695.10.1029/2012JD017695

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refpaperuri:(25e7cc2201392294f080437203d6b7e7)

http://onlinelibrary.wiley.com/doi/10.1029/2012JD017695/fullAbstract Top of page Abstract 1.Introduction 2.Instrumentation 3.Results 4.Conclusions Acknowledgments References [1] This paper presents ozone structures measured by a ground-based ozone lidar and ozonesonde at Huntsville, Alabama, on 2729 April 2010 originating from a stratosphere-to-troposphere transport event associated with a cutoff cyclone and tropopause fold. In this case, the tropopause reached 6km and the stratospheric intrusion resulted in a 2-km thick elevated ozone layer with values between 70 and 85 ppbv descending from the 65306-K to 298-K isentropic surface at a rate of 655kmday 611 . The potential temperature was provided by a collocated microwave profiling radiometer. We examine the corresponding meteorological fields and potential vorticity (PV) structures derived from the analysis data from the North American Mesoscale model. The 2-PVU (PV unit) surface, defined as the dynamic tropopause, is able to capture the variations of the ozone tropopause estimated from the ozonesonde and lidar measurements. The estimated ozone/PV ratio, from the measured ozone and model derived PV, for the mixing layer between the troposphere and stratosphere is 6541 ppbv/PVU with an uncertainty of 6533%. Within two days, the estimated mass of ozone irreversibly transported from the stratospheric into the troposphere is between 0.07 Tg (0.9 10 33 molecules) and 0.11 Tg (1.3 10 33 molecules) with an estimated uncertainty of 59%. Tropospheric ozone exhibited enormous variability due to the complicated mixing processes. Low ozone and large variability were observed in the mid-troposphere after the stratospheric intrusion due to the westerly advection including the transition from a cyclonic system to an anticyclonic system. This study using high temporal and vertical-resolution measurements suggests that, in this case, stratospheric air quickly lost its stratospheric characteristics once it is irreversibly mixed down into the troposphere.

Lefohn A. S., H. Wernli, D. Shadwick, S. Limbach, S. J. Oltmans, and M. Shapiro, 2011: The importance of stratospheric-tropospheric transport in affecting surface ozone concentrations in the western and northern tier of the United States. Atmos. Environ., 45( 28), 4845- 4857.10.1016/j.atmosenv.2011.06.014

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http://www.sciencedirect.com/science/article/pii/S1352231011006078ABSTRACT Stratospheric–tropospheric exchange (STE) processes contribute at both high and low-elevation monitoring sites to background ozone (O3) concentrations. This study addresses the importance of stratospheric intrusions contributing to enhanced hourly average surface O3 concentrations (i.e., 50 ppb) at 12 O3 monitoring stations in the western and northern tier of the US for 2006, 2007, and 2008. The Lagrangian Analysis Tool (LAGRANTO) trajectory model identified specific days when stratosphere-to-troposphere transport was optimal to elevate surface O3 levels. The coincidences between the number of days with a daily maximum hourly average O3 concentration 50 ppb and stratosphere-to-troposphere transport to surface (STT-S > 0) were quantified. The high-elevation site at Yellowstone National Park (NP) in Wyoming exhibited the most coincidences (i.e., more than 19 days a month) during the spring and summer for hourly average O3 concentrations 50 ppb with STT-S > 0 of the 12 monitoring sites. At this site, the daily maximum hourly springtime average O3 concentrations were usually in the 60–70 ppb range. The maximum daily 8-h average concentrations mostly ranged from 50 to 65 ppb. At many of the lower-elevation sites, there was a preference for O3 enhancements to be coincident with STT-S > 0 during the springtime, although summertime occurrences were sometimes observed. When statistically significant coincidences occurred, the daily maximum hourly average concentrations were mostly in the 50–65 ppb range and the daily maximum 8-h average concentrations were usually in the 50–62 ppb range. For many cases, the coincidences between the enhancements and the STT-S events occurred over a continuous multiday period. Supplementary observations, such as (1) the greater frequency of O3 concentration enhancements occurring during the springtime versus other times of the year, (2) the elevation dependency of the frequency of enhancements, (3) the year-to-year variability, (4) the timing of the hour-by-hour occurrences of the O3 concentration enhancements within and across monitoring sites, and (5) the detailed analyses of O3 enhancement events at specific sites, provide additional support for our modeling and statistical results. Our analysis provides an important step in better understanding the variability of natural background O3 concentrations. The study has provided insight into stratospheric intrusions, with emphasis on the combined role of quasi-isentropic large-scale advection and mesoscale boundary layer turbulence for stratospheric air influencing enhanced surface O3.Highlights78 This study addresses the importance of STT with enhanced ozone. 78 A trajectory model was used in the study. 78 Many sites exhibited frequent coincidences between enhanced ozone and STT.

Li D., J. C. Bian, and Q. J. Fan, 2015: A deep stratospheric intrusion associated with an intense cut-off low event over East Asia. Science China Earth Sciences, 58( 1), 116- 128.10.1007/s11430-014-4977-2

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http://www.cnki.com.cn/Article/CJFDTotal-JDXG201501011.htmEuropean Centre for Medium-Range Weather Forecasts Re-Analysis Interim(ERA-Interim)reanalysis data and satellite data,and trajectory model were applied to analyze the dynamical,thermo-dynamical,and chemical structure in the upper troposphere and lower stratosphere(UTLS)of an intense cut-off low(COL)event occurring over East Asia during June 19-23,2010,and to characterize the process and transport pathway of deep stratospheric intrusion.The Atmospheric Infrared Sounder(AIRS)ozone data and the Global Positioning System Ozone(GPSO3)sonde data showed that the air mass originating from the polar formed a region with relatively high values of potential vorticity(PV)and ozone in the center of COL,and a secondary ozone peak appeared in the upper troposphere during mature stage of the COL.Forward trajectory simulation suggested that during the first stage of COL,deep stratospheric intrusion associated with strong northerly wind jet on the west side of the upper-level trough transported ozone-rich air from the polar lower stratosphere into the middle and lower troposphere in the mid-latitude,and increased the ozone concentration there.During the mature stage of the COL,stratospheric air was transported counterclockwise into the troposphere.Backward trajectory model was used to find the source regions of air mass within the COL during its mature stage.Model results show that air masses with high ozone concentration in the center of the COL have two source regions:one is the subpolar vortex which lies in northern part of Center Siberia,where ozone-rich air plays a major role in increasing the ozone concentrations,and the other is the strong shear region which is near by the cyclonic side of the extratropical jet axis(west of 90,near 50).The air masses with low ozone concentration around the COL also have two source regions:one is the anticyclonic side of the extratropical jet axis,where the air mass with the relatively low ozone concentration at the bottom of the COL is mainly controlled by horizontal movement,and the other is the warm area of the south side of COL,where the air mass on the east and west side of the COL is mainly dominated by upward motion.

Lin, M. Y., Coauthors, 2012: Springtime high surface ozone events over the western United States: Quantifying the role of stratospheric intrusions. J. Geophys. Res., 117(D21),D00V22, doi: 10.1029/2012JD018151.10.1029/2012JD018151

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http://onlinelibrary.wiley.com/doi/10.1029/2012JD018151/citedby1] The published literature debates the extent to which naturally occurring stratospheric ozone intrusions reach the surface and contribute to exceedances of the U.S. National Ambient Air Quality Standard (NAAQS) for ground-level ozone (75 ppbv implemented in 2008). Analysis of ozonesondes, lidar, and surface measurements over the western U.S. from April to June 2010 show that a global high-resolution ($50 00 50 km 2) chemistry-climate model (GFDL AM3) captures the observed layered features and sharp ozone gradients of deep stratospheric intrusions, representing a major improvement over previous chemical transport models. Thirteen intrusions enhanced total daily maximum 8-h average (MDA8) ozone to $70-86 ppbv at surface sites. With a stratospheric ozone tracer defined relative to a dynamically varying tropopause, we find that stratospheric intrusions can episodically increase surface MDA8 ozone by 20-40 ppbv (all model estimates are bias corrected), including on days when observed ozone exceeds the NAAQS threshold. These stratospheric intrusions elevated background ozone concentrations (estimated by turning off North American anthropogenic emissions in the model) to MDA8 values of 60-75 ppbv. At high-elevation western U.S. sites, the 25th-75th percentile of the stratospheric contribution is 15-25 ppbv when observed MDA8 ozone is 60-70 ppbv, and increases to $17-40 ppbv for the 70-85 ppbv range. These estimates, up to 2-3 times greater than previously reported, indicate a major role for stratospheric intrusions in contributing to springtime high-O 3 events over the high-altitude western U.S., posing a challenge for staying below the ozone NAAQS threshold, particularly if a value in the 60-70 ppbv range were to be adopted. (2012), Springtime high surface ozone events over the western United States: Quantifying the role of stratospheric intrusions, J. Geophys. Res., 117, D00V22, doi:10.1029/2012JD018151.

Liu C. X., Y. Liu, X. Liu, and K. Chance, 2013: Dynamical and chemical features of a cutoff low over northeast China in July 2007: Results from satellite measurements and reanalysis. Adv. Atmos. Sci.,30(2), 525-540, doi: 10.1007/s00376-012-2086-8.10.1007/s00376-012-2086-8

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http://d.wanfangdata.com.cn/Periodical_dqkxjz-e201302021.aspxThe European Centre for Medium-Range Weather Forecasts Re-Analysis Interim (ERA-Interim) meteorology and measurements from the Microwave Limb Sounder, High Resolution Dynamics Limb Sounder, and Ozone Monitoring Instrument onboard the Earth Observing System Aura satellite were applied to analyze the dynamical and chemical features of a cutoff low (COL) event over northeast China in early July 2007. The results showed the polar stratospheric origin of an upper-level warm-core cyclone at 100-300 hPa, associated with a funnel-shaped tropopause intruding into the mid-troposphere just above the COL center. The impacts of the stratospheric intrusion on both column ozone and ozone profiles were investigated using satellite measurements. When the intensity of the COL peaked on 10 July 2007, the total column ozone (TCO) increase reached a maximum (40-70 DU). This could be dynamically attributed to both the descent of the tropopause (6575%) and the downward transport of stratospheric ozone across the tropopause (6525%). Analysis of the tropospheric ozone profiles provided evidence for irreversible transport/mixing of ozone-rich stratospheric air across the tropopause near the upper-level front region ahead of the COL center. This ozone intrusion underwent downstream transport by the upper tropospheric winds, leading to further increase in TCO by 12-16 DU over broad regions extending from east China toward the northern Japan Sea via South Korea. Meteorological analysis also showed the precedence of the stratospheric intrusion ahead of the development of cyclones in the middle and lower troposphere.

Logan J. A., 1999a: An analysis of ozonesonde data for the lower stratosphere: Recommendations for testing models. J. Geophys. Res., 104( D13), 16151- 16170.10.1029/1999JD900216

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http://onlinelibrary.wiley.com/doi/10.1029/1999JD900216/citedbyABSTRACT . I present an analysis of ozonesonde data with a focus on using these data to evaluate stratospheric models of transport and chemistry. Ozonesondes are the only instruments that provide year-round profiles of ozone throughout the lowermost stratosphere for middle and high latitudes of the Northern Hemisphere. I show vertical profiles and the annual cycle of ozone at selected pressure levels and stations and use TOMS data to evaluate the spatial bias of the sonde stations with respect to zonal mean values of column ozone. Between 10 and 30% of the ozone column is located between 100 hPa and the tropopause at middle and high latitudes, and this region drives much of the seasonal variation of the ozone column. The sonde data allow quantification of the buildup of ozone in the lowermost stratosphere of the Northern Hemisphere in winter and of its loss in late spring and summer. The amount of ozone between the tropopause and 100 hPA in the Northern Hemisphere decreases from 175 t...

Logan J. A., 1999b: An analysis of ozonesonde data for the troposphere: Recommendations for testing 3-D models and development of a gridded climatology for tropospheric ozone. J. Geophy. Res., 104( D13), 16115- 16149.10.1029/1998JD100096

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refpaperuri:(1c62cacb94b1dd88f40398e83a8849ba)

http://onlinelibrary.wiley.com/doi/10.1029/1998JD100096/fullI present an analysis of ozonesonde data, synthesizing what is known about the distribution of tropospheric ozone. Major features of the distribution are highlighted, and recommendations are given for testing three-dimensional models of tropospheric chemistry and transport with these data. The data are analyzed on pressure surfaces and relative to the height of the thermal tropopause. A minimum of 20 soundings are required for 95% confidence intervals of the ozone monthly means to be less than 30% near the extratropical tropopause. Twenty soundings also ensures means reliable to better than 15% for 800-500 hPa for the extratropics and for 800-100 hPa in the tropics. Ozone variability is higher in the upper troposphere for subtropical locations than for tropical locations, and 35 soundings are required for 400-100 hPa for the means to be defined to better than 15%. For northern middle and high latitudes, the broad summer maximum in ozone in the middle troposphere extends all the way up to the tropopause. Median concentrations at the tropopause are highest in June and July, typically 125-200 ppb, and are a factor of 2 smaller in winter. Highest values of ozone are in spring 2 km above the tropopause. The change in the phase of the annual cycle of ozone between the tropopause and the region immediately above it, and the steep concentration gradients across the tropopause, suggest that high vertical resolution (651 km) will be required in models to simulate this behavior. Mean ozone values in the middle troposphere are approximately constant from 30 to 75 in the winter in both hemispheres, while there is a maximum from 35 to 50N in summer. In the northern subtropics, there is a summer minimum in middle tropospheric ozone over the Pacific and a summer maximum over the Atlantic which appear to be related to differences in circulation. Mean ozone values over Samoa are similar to those measured 20-30 years ago over Panama. Ozone is higher over the tropical South Atlantic (Natal) than over the western Pacific (Samoa) all year from about 800 hPa to the tropopause; ozone is most similar in May and June over the Atlantic and Pacific, the months with minimum burning in the tropics. The ozone maximum at Samoa in the middle and upper troposphere in October is caused by long-range transport of ozone and its precursors from biomass burning, with the peak lagging that at Natal by about a month. The secondary peak in ozone in January and December at South Atlantic sites reflects transport of biomass burning effluents from the Northern Hemisphere. The sonde data were used in combination with surface and satellite data to derive a gridded climatology for tropospheric ozone.

Mauzerall D. L., D. Narita, H. Akimoto, L. Horowitz, S. Walters, D. A. Hauglustaine, and G. Brasseur, 2000: Seasonal characteristics of tropospheric ozone production and mixing ratios over East Asia: A global three-dimensional chemical transport model analysis. J. Geophys. Res., 105( D14), 17895- 17910.10.1029/2000JD900087

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http://onlinelibrary.wiley.com/doi/10.1029/2000JD900087/pdfABSTRACT We examine seasonal and geographical distributions of tropospheric ozone production and mixing ratios over East Asia with a global three-dimensional chemical transport model called Model of Ozone and Related Tracers, version 1 (MOZART 1). Net ozone production within the East Asian boundary layer exhibits three distinct seasonal cycles depending on region (north of 20N, 5-20N and south of 5N). North of 20N, net ozone production over East Asia from spring through autumn is found to have a maximum extending from 25N-40N and from central eastern China to Japan, resulting from the strong emission and transport of anthropogenic O3 precursors. In winter, maximum O3 production in this region occurs between 20N and 30N. This is a region of long-range transport. Over the Indochina peninsula, between 5N and 20N, net O3 production is controlled by the seasonal cycle between wet and dry seasons and has

Nieto R., Coauthors, 2005: Climatological features of cutoff low systems in the northern hemisphere. J.Climate, 18( 6), 3085- 3103.10.1175/JCLI3386.1

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http://www.researchgate.net/publication/249611502_Climatological_Features_of_Cutoff_Low_Systems_in_the_Northern_HemisphereAbstract This study presents the first multidecadal climatology of cutoff low systems in the Northern Hemisphere. The climatology was constructed by using 41 yr (1958-98) of NCEPCAR reanalysis data and identifying cutoff lows by means of an objective method based on imposing the three main physical characteristics of the conceptual model of cutoff low (the 200-hPa geopotential minimum, cutoff circulation, and the specific structure of both equivalent thickness and thermal front parameter fields). Several results were confirmed and climatologically validated: 1) the existence of three preferred areas of cutoff low occurrence (the first one extends through southern Europe and the eastern Atlantic coast, the second one is the eastern North Pacific, and the third one is the northern Chinaiberian region extending to the northwestern Pacific coast; the European area is the most favored region); 2) the known seasonal cycle, with cutoff lows forming much more frequently in summer than in winter; 3) the short lifetime of cutoff lows, most cutoff lows lasted 2-3 days and very few lasted more than 5 days; and 4) the mobility of the system, with few cutoff lows being stationary. Furthermore, the long study period has made it possible (i) to find a bimodal distribution in the geographical density of cutoff lows for the European sector in all the seasons (with the exception of winter), a summer displacement to the ocean in the American region, and a summer extension to the continent in the Asian region, and (ii) to detect northward and westward motion especially in the transitions from the second to third day of occurrence and from the third to fourth day of occurrence. The long-term cutoff low database built in this study is appropriate to study the interannual variability of cutoff low occurrence and the links between cutoff lows and jet stream systems, blocking, or major modes of climate variability as well as the global importance of cutoff low in the stratosphere roposphere exchange mechanism, which will be the focus of a subsequent paper.

Nikulin M. S., 2001: Hellinger distance. Encyclopeadia of Mathematics. Ulf Rehmann et al., Eds., Springer. [Available online at http://www.encyclopediaofmath.org/index.php?title=h/h046890]

Ojha N., Coauthors, 2014: On the processes influencing the vertical distribution of ozone over the central Himalayas: Analysis of yearlong ozonesonde observations. Atmos. Environ., 88, 201- 211.10.1016/j.atmosenv.2014.01.031

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http://www.sciencedirect.com/science/article/pii/S1352231014000491First yearlong (2011) balloon-borne measurements of ozone vertical distribution (EN-SCI 2ZV7 ECC Ozonesonde) and meteorological parameters (iMet-1-RSB 403 MHz GPS Radiosonde) over Nainital (79.5E, 29.4N, 1958 m amsl) in the central Himalayas are presented. Lower tropospheric ozone shows a prominent seasonality with highest levels during spring (6570-110 ppbv in May) and lowest levels during summer-monsoon (6520-50 ppbv), which is consistent with the ground-based observations. The lower tropospheric ozone minimum coincides with highest values of relative humidity (80-100%) during the summer-monsoon. However, ozone mixing ratios in the middle-upper troposphere show less pronounced and different seasonality. Influences of subtropical jets are observed (wind speed: 6540-80 m s) in the middle-upper troposphere, particularly during winter. A stratospheric intrusion event during winter is observed, which enhances the ozone levels by 65180% in the middle-upper troposphere. A noticeable feature of secondary ozone peaks (65140-250 ppbv) is observed in the middle troposphere (658-12 km), more frequently during spring. Ozone levels in 2-4 km altitude range are higher by 19.9 4.6 ppbv during the springtime high fire activity period over the northern India. Moreover, the lower tropospheric ozone levels over Nainital during spring are found to be considerably (6530 ppbv) higher than those over Ahmedabad in the western India. This ozone enhancement is attributed mainly to the regional pollution of the Indo-Gangetic Plain (IGP) supplemented with the northern Indian biomass burning. It is suggested that regional photochemistry and biomass burning processes play controlling role in the lower troposphere, while, the middle-upper tropospheric variations are driven by dynamical processes including advection and stratospheric intrusion.

Oltmans S.J., Coauthors, 1996: Summer and spring ozone profiles over the North Atlantic from ozonesonde measurements. J. Geophys. Res., 101( D22), 29179- 29200.10.1029/96JD01713

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F96JD01713%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/96JD01713/abstractOzone profiles obtained by near-daily ozonesonde observations during campaigns at several sites in the North Atlantic are used to construct time-height cross sections of ozone concentration through the troposphere. Strong day-to-day ozone variability on the scale of synoptic meteorological disturbances is found both in the spring and in the summer throughout much of the troposphere. Layers of high ozone concentration (100 ppb) are frequently seen in the middle and upper troposphere and are invariably associated with transport characteristics that strongly support a stratospheric source for these layers. Regions of low ozone (<40 ppb) are seen in the middle and upper troposphere associated with higher relative humidity. The connection of these events with low surface mixing ratios suggests that convective processes mix air low in ozone up through the troposphere. Vertical layering of ozone mixing ratio, which is seen at all of the observing locations, is a result of differing sources of air in the different layers.

Pan L. L., W. J. Rand el, B. L. Gary, M. J. Mahoney, and E. J. Hintsa, 2004: Definitions and sharpness of the extratropical tropopause: A trace gas perspective. J. Geophys. Res., 109(D23),D23103, doi: 10.1029/2004JD004982.10.1029/2004JD004982

703c260c1d4a033d63d70ed86be3afdf

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2004JD004982%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/2004JD004982/abstract[1] Definitions of the extratropical tropopause are examined from the perspective of chemical composition. Fine-scale measurements of temperature, ozone, carbon monoxide, and water vapor from approximately 70 aircraft flights, with ascending and descending tropopause crossings near 40N and 65N, are used in this analysis. Using the relationship of the stratospheric tracer O 3 and the tropospheric tracer CO, we address the issues of tropopause sharpness and where the transitions from troposphere to stratosphere occur in terms of the chemical composition. Tracer relationships indicate that mixing of stratospheric and tropospheric air masses occurs in the vicinity of the tropopause to form a transition layer. Statistically, this transition layer is centered on the thermal tropopause. Furthermore, we show that the transition is much sharper near 65N (a region away from the subtropical jet) but spans a larger altitude range near 40N (in the vicinity of the subtropical jet). This latter feature is consistent with enhanced stratosphere-troposphere exchange and mixing activity near the tropopause break.

Pan, L. L., Coauthors, 2007: Chemical behavior of the tropopause observed during the Stratosphere-Troposphere Analyses of Regional Transport experiment. J. Geophys. Res.,112(D18), 893-907, doi: 10.1029/2007JD008645.10.1175/2009BAMS2865.1

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1b8c712e8df908781e32891fc923d66d

http%3A%2F%2Fwww.cabdirect.org%2Fabstracts%2F20103147807.html

refpaperuri:(45615a2e8bb1dd592a9db7e538250a66)

http://www.cabdirect.org/abstracts/20103147807.htmlAbstract The Stratosphere roposphere Analyses of Regional Transport 2008 (START08) experiment investigated a number of important processes in the extratropical upper troposphere and lower stratosphere (UTLS) using the National Science Foundation (NSF)CAR Gulfstream V (GV) research aircraft. The main objective was to examine the chemical structure of the extratropical UTLS in relation to dynamical processes spanning a range of scales. The campaign was conducted during Aprilune 2008 from Broomfield, Colorado. A total of 18 research flights sampled an extensive geographical region of North America (25-65N, 80-120W) and a wide range of meteorological conditions. The airborne in situ instruments measured a comprehensive suite of chemical constituents and micro-physical variables from the boundary layer to the lower stratosphere, with flights specifically designed to target key transport processes in the extratropical UTLS. The flights successfully investigated stratosphereroposphere exchange (STE) processes, including the intrusion of tropospheric air into the stratosphere in association with the secondary tropopause and the intrusion of stratospheric air deep into the troposphere. The flights also sampled the influence of convective transport and lightning on the upper troposphere as well as the distribution of gravity waves associated with multiple sources, including fronts and topography. The aircraft observations are complemented by satellite observations and modeling. The measurements will be used to improve the representation of UTLS chemical gradients and transport in Chemistrylimate models (CCMs). This article provides an overview of the experiment design and selected observational highlights.

Pan, L. L., Coauthors, 2009: Tropospheric intrusions associated with the secondary tropopause. J. Geophys. Res.,114(D10), doi: 10.1029/2008JD011374.10.1029/2008JD011374

fa2fc3f720ae4f5c7df549485df18707

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2008JD011374%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2008JD011374/pdfABSTRACT [1] Deep intrusions of tropospheric air into the lower stratosphere above the subtropical jet are investigated using new observations and meteorological analyses. These intrusions are characterized by low ozone concentration and low static stability. The low-ozone layer is consistently observed from ozonesonde profiles and satellite remote sensing data from Aura/HIRDLS. The intruding layer occurs along and under the poleward extending tropical tropopause, which becomes the secondary tropopause in middle to high latitudes. The association of the ozone and the thermal structure provides evidence for the physical significance of the subtropical tropopause break and the secondary tropopause. The core of the intruding layer is typically between 370 and 400 K potential temperature (-15 km), but the vertical extent of the intrusion can impact ozone above 400 K, the lower boundary of the overworld. Two intrusion events over the continental United States in the spring of 2007 are analyzed to show the spatial extent and the temporal evolution of the intruding air mass. These examples demonstrate the effectiveness of potential temperature lapse rate, i.e., static stability, as a diagnostic for the intrusion event. Comparison with the potential vorticity field is made to show the complementarity of the two dynamical fields. The static stability diagnostic provides a tool to map out the horizontal extent of the intruding layer and to investigate its evolution. Furthermore, the diagnostic makes it possible to forecast the intrusion event for field studies.

Pittman, J. V., Coauthors, 2009: Evaluation of AIRS, IASI, and OMI ozone profile retrievals in the extratropical tropopause region using in situ aircraft measurements. J. Geophys. Res., 114(D24),D24109, doi: 10.1029/2009JD012493.10.1029/2009JD012493

b6541a0ce32fdbd391a507301c492cf0

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2009JD012493%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/2009JD012493/full[1] We evaluate ozone profile retrievals from the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Ozone Monitoring Instrument (OMI) using in situ measurements collected on board the NSF/NCAR Gulfstream-V aircraft during the Stratosphere-Troposphere Analyses of Regional Transport 2008 (START08) experiment. The focus of this study is to examine how well the satellite retrieval products capture the ozone gradients and variability in the extratropical upper troposphere lower stratosphere (UTLS). The AIRS retrieval examined is version 5, while IASI and OMI retrievals are research products. All satellite instruments show excellent ability in capturing synoptic-scale ozone gradients associated with strong potential vorticity (PV) gradients. The positive ozone-PV correlation near the tropopause is also well represented in the satellite data in comparison to collocated aircraft measurements. During aircraft cruise legs, more than 90% of collocated satellite retrievals agree with aircraft measurements within 50% for ozone mixing ratios greater than 200 ppbv. Below 200 ppbv, AIRS and IASI retrievals show significant positive biases, while OMI shows both positive and negative biases. Ozone gradients across the tropopause are well-captured, with median values within 30% (positive for AIRS and IASI, negative for OMI) and variances within 50%. Ozone variability in the UTLS is captured by the satellite retrievals at the 80% level. In the presence of high clouds, however, the infrared retrievals show the largest positive biases. Despite the limited vertical information content, the high horizontal coverage and long-term data availability make these satellite data sets a valuable asset for UTLS research.

Price J. D., G. Vaughan, 1993: The potential for stratosphere-troposphere exchange in cut-off-low systems. Quart. J. Roy.Meteor. Soc., 119( 510), 343- 365.10.1002/qj.49711951007

ee72be15dbd3124873d7eb795404d7b1

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fqj.49711951007%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1002/qj.49711951007/abstractAbstract Three mechanisms are discussed associated with cut-off-low (COL) systems which can transfer stratospheric air into the troposphere. These mechanisms are: (i) convective erosion of the tropopause, (ii) erosion of the tropopause by turbulence associated with a jet stream, and (iii) tropopause folding around the flank of a COL. Three case studies are presented which examine the first two of these processes and provide evidence that stratosphere-troposphere exchange (STE) had occurred. Furthermore, results suggest that periodic reintensification of some COLs cause all these processes to recur or be prolonged. Their relative importance to STE is discussed and an estimate for that occurring by mechanism (i) is given for one of the case studies. Statistical data on annual COL numbers are used to calculate and annual mean transfer of ozone by this mechanism, which is found to be no more than 4% of the annual transfer for the northern hemisphere. This result suggests that convective STE in COLs is a minor contributor to the northern hemisphere STE.

Rand el, W. J., D. J. Seidel, L. L. Pan, 2007: Observational characteristics of double tropopauses. J. Geophys. Res.,112(D7), doi: 10.1029/2006JD007904.10.1029/2006JD007904

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2006JD007904%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1029/2006JD007904/pdf[1] Temperature profiles in the extratropics often exhibit multiple tropopauses (as defined using the lapse rate definition). In this work we study the observational characteristics of double tropopauses based on radiosondes, ERA40 reanalysis, and GPS radio occultation temperature profiles. Double tropopauses are associated with a characteristic break in the thermal tropopause near the subtropical jet, wherein the low latitude (tropical) tropopause extends to higher latitudes, overlying the lower tropopause; this behavior can extend to polar latitudes. Tropopause statistics derived from radiosondes and GPS data show good agreement, and GPS data allow mapping of double tropopause characteristics over the globe. The occurrence frequency shows a strong seasonal variation over NH midlatitudes, with 6550–70% occurrence in profiles during winter, and a small fraction (6510%) over most of the hemisphere during summer (with the exception of a localized maximum over the poleward flank of the Asian monsoon anticyclone). SH midlatitude statistics show a smaller seasonal variation, with occurrence frequencies of 6530–50% over the year (maximum during winter). Over the extratropics, the occurrence frequency is substantially higher for cyclonic circulation systems. Few double tropopauses are observed in the tropics. Ozone measurements from balloons and satellites show that profiles with double tropopauses exhibit systematically less ozone in the lower stratosphere than those with a single tropopause. Together with the meteorological data, the ozone observations identify double tropopauses as regions of enhanced transport from the tropics to higher latitudes above the subtropical jet cores.

Srivastava S., S. Lal, M. Naja, S. Venkataramani, and S. Gupta, 2012: Influence of regional pollution and long range transport over western India: Analysis of ozonesonde data. Atmos. Environ., 47, 174- 182.10.1016/j.atmosenv.2011.11.018

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http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1352231011012015

refpaperuri:(d9ea9bfb8afa9b563c2b955829d834a0)

http://www.sciencedirect.com/science/article/pii/S1352231011012015Four years (April 2003 July 2007) of ozonesonde observations over Ahmedabad have been studied for the first time using ten days backward trajectories in the boundary layer (lower 2km) and lower troposphere (2.5-4km). Ozone data are classified according to the residence times of air-masses over the North-Western India (NWI), marine and Northern Africa/Southern Europe (NASE) regions. Ozone increases linearly with increasing residence days over the NWI region for about six days with maximum increase rate (boundary layer 654.51.1ppbv/day, lower troposphere 653.40.8ppbv/day) during spring and minimum during winter (boundary layer 650.70.8ppbv/day, lower troposphere 650.80.7ppbv/day). The analysis of surface ozone over Ahmedabad confirms that ozone increase with residence days is largely due to photochemical build up. The estimated background ozone corresponding to zeroth residence day is found to be significantly lower during summer-monsoon (6526.33.3ppbv) than winter (6547.73.2ppbv) within the boundary layer. The air masses mainly influenced by NWI region, marine and NASE regions are termed as regionally polluted, marine and long range transport (LRT) respectively. The regionally polluted ozone is found to be higher than the average ozone during spring and summer-monsoon by 2241% within the boundary layer and by 912% in the lower troposphere. The marine air shows lower ozone by 38% and 10% during spring and summer seasons respectively in the boundary layer. LRT plays a significant role in the lower troposphere during spring and summer seasons with an ozone enhancement of 9% and 27% respectively. The present work suggests that regional pollution and long range transport have significant influence on the seasonal distribution of ozone in the lower troposphere whereas the background ozone levels in summer-monsoon are mainly influenced by marine air mass over this region.

Sun L., X. Y. Zheng, and Q. Wang, 1994: The climatological characteristics of northeast cold vortex in China. Quarterly Journal of Applied Meteorology, 5( 3), 297- 303. (in Chinese)9fa35e18dfc418e328d0952575b271e4

http%3A%2F%2Fen.cnki.com.cn%2FArticle_en%2FCJFDTOTAL-YYQX403.005.htm

http://en.cnki.com.cn/Article_en/CJFDTOTAL-YYQX403.005.htmA climatological andlysis of spatial and temporal distfribution of the nortHeast coldvortex in China during the period 1956-1990 and their relationship with the generalcirculation over East Asia is presented based on Beijing Meteorological Centerhistorical weather map. The results show: The frequency of northeast cold vortex hassignificant continuity , interannual variability, inter-monthly change and the low-frequency variation. And they trend to appear in the regions of low-lying landgenerally, such as Northeast Plain and Three-River Plain,especially the developingnortheast cold vortex also relates to the contrast of ocean-land distribution. Thevariations of the frequency and location of the northeast cold vortex are characterized byateleconnection structure at 500 hPa in East Asia. The effective factors are mainlyconcerned with the location and intensity of the blocking over East Asia and subtropicalhigh.

Tilmes, S., Coauthors, 2012: Technical Note: Ozonesonde climatology between 1995 and 2011: Description, evaluation and applications. Atmospheric Chemistry and Physics, 12( 16), 7475- 7497.10.5194/acp-12-7475-2012

0e589f6f6c7a4b40d112c685b36630b5

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F1368406

http://www.oalib.com/paper/1368406An ozone climatology based on ozonesonde measurements taken over the last 17 yr has been constructed for model evaluation and comparisons to other observations. Vertical ozone profiles for 42 stations around the globe have been compiled for the period 1995-20, in pressure and tropopause-referenced altitudes. For each profile, the mean, standard deviation, median, the half-width are provided, as well as information about interannual variability. Regional aggregates are formed in combining stations with similar ozone characteristics. The Hellinger distance is introduced as a new diagnostic to identify stations that describe similar shapes of ozone probability distribution functions (PDFs). In this way, 12 regions were selected covering at least 2 stations and the variability among those stations is discussed. Significant variability with longitude of ozone distributions in the troposphere and lower stratosphere in the northern mid- and high latitudes is found. The representativeness of regional aggregates is discussed for high northern latitudes, Western Europe, Eastern US, Japan, using independent observations from surface stations and MOZAIC aircraft data. Good agreement exists between ozonesondes and aircraft observations in the mid-troposphere and between ozonesondes and surface observations for Western Europe. For Eastern US and high northern latitudes, surface ozone values from ozonesondes are biased 10ppb high compared to independent measurements. An application of the climatology is presented using the NCAR CAM-Chem model. The climatology allows evaluation of the model performance regarding ozone averages, seasonality, interannual variability, the shape of ozone distributions. The new assessment of the key features of ozone distributions gives deeper insights into the performance of models.

Wang G. C., Q. X. Kong, H. B. Chen, Y. J. Xuan, and X. W. Wan, 2004b: Characteristics of ozone vertical distribution in the atmosphere over Beijing. Advance in Earth Science, 19( 5), 743- 748. (in Chinese)

Wang G. C., Q. X. Kong, Y. J. Xuan, X. W. Wan, H. B. Chen, S. Q. Ma, and Q. Zhao, 2004a: Preliminary analysis on parallel comparison of GPSO3 and Vaisala ozonesondes. J. Appl. Meteor. Sci., 15( 6), 672- 680. (in Chinese)79d30d31baa16b20b211f2c252904b72

http%3A%2F%2Fqk.cams.cma.gov.cn%2Fjams%2Fch%2Freader%2Fview_abstract.aspx%3Ffile_no%3D20040682%26flag%3D1

http://qk.cams.cma.gov.cn/jams/ch/reader/view_abstract.aspx?file_no=20040682&flag=1

Wang, Y., Coauthors, 2012: Tropospheric ozone trend over Beijing from 2002-2010: Ozonesonde measurements and modeling analysis. Atmospheric Chemistry and Physics, 12( 18), 8389- 8399.10.5194/acp-12-8389-2012

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http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F258563770_Tropospheric_ozone_trend_over_Beijing_from_2002-2010_ozonesonde_measurements_and_modeling_analysis

refpaperuri:(70f8fff4a442bbab204ca1c213f9dabc)

http://www.researchgate.net/publication/258563770_Tropospheric_ozone_trend_over_Beijing_from_2002-2010_ozonesonde_measurements_and_modeling_analysisUsing a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS), the trend of tropospheric ozone (O3) during 2002-2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone for the entire time series is 4.6%yr-1 for a mean level of 52 DU. This trend is close to the significant trend of partial column ozone in the lower troposphere (0--3 km) during summer (3.4%yr-1 for a mean level of 23 DU). Analysis of the CLaMS simulation shows that transport rather than chemistry drives most of the seasonality of tropospheric ozone. However, dynamical processes alone cannot explain the trend of tropospheric ozone in the observational data. Clearly enhanced ozone values and a negative vertical ozone gradient in the lower troposphere in the observational data emphasize the importance of photochemistry within the troposphere during spring and summer, and suggest that the photochemistry within the troposphere significantly contributed to the tropospheric ozone trend over Beijing during the last decade.

Wirth V., 1995: Diabatic heating in an axisymmetric cut-off cyclone and related stratosphere-troposphere exchange. Quart. J. Roy. Meteor. Soc., 121( 521), 127- 147.1597e7004497b4fca59212995b5968f6

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fqj.49712152107%2Fcitedby

http://onlinelibrary.wiley.com/doi/10.1002/qj.49712152107/citedby

WMO, 1957: Meteorology: A three-dimensional science: Second session of the Commission for Aerology. WMO Bull., 6, 134- 138.

Xie F. Q., X. H. Cai, 2000: Spatial and temporal variation of total ozone over East-Asia. Acta Scientiae Circumstantiae, 20( 5), 513- 517. (in Chinese)8bd30c01-49c3-4655-a026-90132762541b

115200020521

eded4957de28879c78ad3216ccdd7dfd

http%3A%2F%2Fen.cnki.com.cn%2FArticle_en%2FCJFDTotal-HJXX200005000.htm

http://en.cnki.com.cn/Article_en/CJFDTotal-HJXX200005000.htmSpatial and temporal variation of total ozone over an East\|Asia region which mainly include mainland of China was analyzed.TOMS (Total Ozone Mapping Spectrometer) data were used for this work.It showed that the average concentration over this region was approximately 307DU (Dobson Unit),while a seasonal evolution exists with a variation magnitude about 50DU.The mean concentration over this region reached its maximum at March and a minimum at October yearly.Strong latitudinal variation was shown by the distribution of ozone concentration,with lower values at lower latitudes while higher ones at higher latitudes.One\|peak probability distribution of ozone concentration was shown in this region,with narrower peak at low latitudes and broad one at higher latitudes.A mean reduction of total ozone approximating to 10DU was obvious in the period from 1978 to 1994.Correspondent to a more or less even reduction at different concentration levels,appearance probability of lower concentrations increased and probability of higher concentrations decreased in this period.

Xuan Y. J., S. Q. Ma, H. B. Chen, G. C. Wang, Q. X. Kong, Q. Zhao, and X. W. Wan, 2004: Intercomparisons of GPSO3 and Vaisala ECC ozone sondes. Plateau Meteorology, 23( 3), 394- 399. (in Chinese)00b50aa6-8ccb-42a5-8f71-f5158dd42031

mag484262004233394

Ozone sonde is widely used for in situ measurements of atmospheric ozone profiles from ground to 35 km.In order to obtain the measured precision, sensitivity and reliability of Chinese ozone sonde named GPSO<sub>3</sub>, a series intercomparison with Vaisala ECC type ozone sonde has been carried, including the sensitivity and response time of ozone sensors, ozone measurements at ground in comparison with that by a standard ozone analyzer, the pump efficiency at low pressure, and balloon soundings with two sondes together.The results show that our GPSO<sub>3</sub> ozone sensor has the capability similar to that of Vaisala ECC ozone sonde.

Yang J., D. R. LÜ, 2003: A simulation study of Stratosphere-troposphere exchange due to Cut-off-low over Eastern Asia. Chinese J. Atmos. Sci., 27( 6), 1031- 1044. (in Chinese)10.1007/BF02948883

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http%3A%2F%2Fen.cnki.com.cn%2Farticle_en%2Fcjfdtotal-dqxk200306006.htm

refpaperuri:(7e95b58387dc6eff664db9990e03182c)

http://en.cnki.com.cn/article_en/cjfdtotal-dqxk200306006.htmMesoscale model (MM5) is used to simulate a strong process of stratosphere troposphere exchange (STE) due to cut off low over Eastern Asia (grid center: 45 N, 120 E; simulated time: 8-12 April 2002) The total net mass from stratosphere to troposphere calculated by Wei formula is 5 0 10 14 kg, corresponding to 0 72 10 -3 kg m -2 s -1 The results show that the tropopause folding appears in the entrance of jet stream and upper front zone due to the interaction of the surface front and the upper front The horizontal movement of air is the primary contributor to the STE According to historical climate recorder, the annual mean number of cut off lows in eastern Asia(20-70 N,80-180 E) is 60 accounting for 52% of total polar type cut off lows in the Northern Hemisphere All above show the significant contribution of eastern Asia STE to global STE

Yates, E. L., Coauthors, 2013: Airborne observations and modeling of springtime stratosphere-to-troposphere transport over California. Atmospheric Chemistry and Physics, 13( 24), 12 481- 12 494.

Zhang J. Q., Y. J. Xuan, X. L. Yan, M. Y. Liu, H. M. Tian, X. A. Xia, L. Pang, and X. D. Zheng, 2014a: Development and preliminary evaluation of a double-cell ozonesonde. Adv. Atmos. Sci.,31(4), 938-947, doi: 10.1007/s00376-013-3104-1.10.1007/s00376-013-3104-1

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http%3A%2F%2Fwww.cqvip.com%2FQK%2F84334X%2F201404%2F49968212.html

refpaperuri:(f449592dc1950e1d8204b11d53087d1b)

http://d.wanfangdata.com.cn/Periodical_dqkxjz-e201404018.aspxOzonesondes are widely used to obtain ozone concentration profiles from the surface to the upper atmosphere. A kind of double-cell ozonesonde has been developed at the Institute of Atmospheric Physics(IAP), Chinese Academy of Sciences(named the "IAP ozonesonde") based on previous experience over the past 20 years of developing the singlecell GPSO3 ozonesonde. The IAP ozonesonde is of the Electrochemical Concentration Cell(ECC) type. A detailed description of the IAP ozonesonde is firstly provided in the present paper, followed by a presentation of results from a series of launches carried out to evaluate its performance. The analysis involved comparing its observations with measurements from the GPSO3 and ECC ozonesondes(Model type ENSCI-Z) as well as a Brewer spectrophotometer. The results showed that the IAP ozonesonde is a vast improvement over the GPSO3 ozonesonde, able to capture vertical ozone structures very well and in good agreement with ECC ozonesonde measurements. The average difference in the ozone partial pressure between the IAP and ECC ozonesondes was 0.3 mPa from the surface to 2.5 km, close to zero from 2.5 to 9 km and generally less than 1 mPa for layers higher than 9 km. The apparent deviation is likely caused by a decreasing pump flow rate in the IAP ozonesonde which needs further improvement. The total ozone amounts measured by the IAP ozonesonde profiles were highly comparable with the Brewer data with a relative difference of 6%. The development of the IAP ozonesonde and its strong performance will surely accelerate the process of conventional observations of ozone profiles over China in the near future as well as provide more data for ozone research in general.

Zhang J. Q., Y. J. Xuan, X. A. Xia, M. Y. Liu, X. L. Yan, L. Pang, Z. X. Bai, and X. W. Wan, 2014b: Performance evaluation of a Self-developed ozonesonde and its application in an intensive observational campaign. Atmos. Oceanic Sci. Lett., 7( 3), 175- 179.10.3878/j.issn.1674-2834.13.0089

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http%3A%2F%2Fd.wanfangdata.com.cn%2FPeriodical_dqhhykxkb201403002.aspx

http://d.wanfangdata.com.cn/Periodical_dqhhykxkb201403002.aspxTo make a detailed test on the reliability and detection performance of the electrochemical concentration cell (ECC) type ozonesonde which had been developed and preliminarily evaluated by the authors, an intensive ozonesonde release experiment was held at two sites in Beijing and Changchun in June 2013. The results showed that the mean background current and its standard deviation were 0.03 (0.04) muA and 0.02 (0.03) muA in Beijing (Changchun). The average response time and its standard deviation were 27.8 s (30.4 s) and 4.0 s (3.7 s) in Beijing (Changchun). The ozone partial pressure profiles at both sites showed a central peak in the stratosphere and a side peak in the boundary layer. Large variation in ozone partial pressure was observed at the middle levels of the atmosphere (10-17 km). A more marked gradient of ozone change was observed in Beijing (3.4 mPa km~(-1)) at the lower atmosphere level, as compared to that in Changchun (0.4 mPa km~(-1)). The results presented in this paper indicate that this self-developed ozonesonde shows a high level of reliability and good performance. The ozonsonde is expected to play an important role in operational observations of ozone profiles.

Zhang M., W. S. Tian, L. Chen, and D. R. LÜ, 2010: Cross-tropopause mass exchange associated with a tropopause fold event over the northeastern Tibetan Plateau. Adv. Atmos. Sci.,27(6), 1344-1360, doi: 10.1007/s00376-010-9129-9.10.1007/s00376-010-9129-9

d95bde80b74b9a5a236e138691198ae8

http%3A%2F%2Fwww.cqvip.com%2Fqk%2F84334x%2F201006%2F35559682.html

http://d.wanfangdata.com.cn/Periodical/dqkxjz-e201006011A springtime tropopause fold event, found to be related to a cold trough intrusion from the north, was detected in the northeastern Tibetan Plateau (TP) based on various observations. A nested high-resolution mesoscale model was employed to investigate the effect of orography on the stratosphere-troposphere exchange. The model was found to be able to capture plausible tropopause fold properties. The propagation of the tropopause fold changed significantly when the terrain height in the model was altered. However, decreasing the terrain height had no significant effect on the morphology of folds. When a fold passed over an elevated surface, a leeside jet stream and a layer of humid air in the middle troposphere tended to develop. This strong leeside descent of air masses and high mid-level potential instability (PI) could give rise to deep upward motions in the leeside and inject tropospheric air into the lower stratosphere. Besides, when the flow encounters an elevated surface, forced lifting together with mid-level PI can trigger deep convective motions on the windward slope. The troposphere to stratosphere transport was found to be persistent and almost stationary over the windward slope of the TP during the evolution of the fold.