夏季亚洲季风区是对流层向平流层物质输送的主要通道,其对平流层水汽的变化有重要贡献。以往的研究表明亚洲季风区向平流层的水汽传输主要在青藏高原及周边地区。本文利用多年平均的逐日ERAi、MERRA再分析数据和微波临边观测仪(Microwav...夏季亚洲季风区是对流层向平流层物质输送的主要通道,其对平流层水汽的变化有重要贡献。以往的研究表明亚洲季风区向平流层的水汽传输主要在青藏高原及周边地区。本文利用多年平均的逐日ERAi、MERRA再分析数据和微波临边观测仪(Microwave Limb Sounder,MLS)数据,首先对比分析夏季青藏高原周边上空水汽的分布特征,再利用再分析资料分析了对流层—平流层水汽传输的特征。结果表明:青藏高原周边特定的等熵面和对流层顶结构分布有利于水汽向平流层的绝热输送;在南亚高压的东北侧,从青藏高原到中太平洋地区,340～360 K层次存在最为显著的水汽向平流层的纬向等熵绝热输送通道,7～8月平均输送强度可达约7×103 kg s-1。此外,在伊朗高原及南亚高压的西部,350～360 K层次也存在一支水汽向平流层的经向等熵绝热输送通道,但强度相对较弱(约2.5×103kgs-1)。在青藏高原南侧370～380K层次存在强的水汽向平流层的非绝热输送,主要由深对流和大尺度上升运动引起,7～8月平均输送强度约0.4×103 kg s-1。落基山以东到大西洋西部,350～360 K层次存在水汽向平流层的纬向等熵绝热输送通道,但强度也弱得多(约2.5×103 kg s-1)。展开更多
本文利用逐年7~8月平均的ERA-Interim再分析资料并结合SWOOSH(Stratospheric water and ozone satellite homogenized)水汽数据,分析了青藏高原及周边地区330~360 K层次水汽质量分布的年际异常特征及其成因。结果表明,水汽质量分布异常...本文利用逐年7~8月平均的ERA-Interim再分析资料并结合SWOOSH(Stratospheric water and ozone satellite homogenized)水汽数据,分析了青藏高原及周边地区330~360 K层次水汽质量分布的年际异常特征及其成因。结果表明,水汽质量分布异常表现为整体异常型、东西偶极异常型和南北偶极异常型三个主导分布型。整体异常型在水汽质量整体偏多时,青藏高原地区对流和垂直向上的水汽质量非绝热传输偏强,上对流层为异常偏强的水汽质量非绝热辐合;此时对应南亚高压偏强,青藏高原地区上对流层的水汽质量绝热辐散和高原以西地区的水汽质量绝热辐合都异常偏强,水汽质量整体偏少时则相反。东西偶极异常型水汽质量呈西多/东少分布时,青藏高原西部(中东部)对流和垂直向上的水汽质量非绝热传输异常偏强(弱),上对流层的水汽质量非绝热辐合和水汽质量绝热辐散也异常偏强(偏弱);同时对应南亚高压偏西,青藏高原以西到伊朗高原的上对流层有异常的自东向西的水汽质量绝热输送和水汽质量绝热辐合。水汽质量呈西少/东多分布时则有相反的结果。南北偶极异常型水汽质量呈北多/南少分布时,对应南亚高压偏北,青藏高原北部的上对流层有异常自南向北的水汽质量绝热输送所造成的水汽质量辐合,同时该地区低层异常偏强的自下向上的水汽质量非绝热输送也加强水汽质量辐合,而青藏高原南侧上对流层则为异常偏弱的水汽质量绝热辐散和水汽质量非绝热辐合,水汽质量呈北少/南多分布时相反。展开更多
A parallel comparison is made of the circulation climatology and the leading oscillation mode of the northern winter stratosphere among six reanalysis products and 24 CMIP5 （Coupled Model Intercomparison Project Phas...A parallel comparison is made of the circulation climatology and the leading oscillation mode of the northern winter stratosphere among six reanalysis products and 24 CMIP5 （Coupled Model Intercomparison Project Phase 5） models. The results reveal that the NCEP/NCAR, NECP/DOE, ERA40, ERA-Interim and JRA25 reanalyses are quite consistent in describ- ing the climatology and annual cycle of the stratospheric circulation. The 20CR reanalysis, however, exhibits a remarkable ＂cold pole＂ bias accompanied by a much stronger stratospheric polar jet, similar as in some CMIP5 models. Compared to the 1-2 month seasonal drift in most coupled general circulation models （GCMs）, the seasonal cycle of the stratospheric zonal wind in most earth system models （ESMs） agrees very well with reanalysis. Similar to the climatology, the amplitude of Polar Vortex Oscillation （PVO） events also varies among CMIP5 models. The P^O amplitude in most GCMs is relatively weaker than in reanalysis, while that in most of the ESMs is more realistic. In relation to the ＂cold pole＂ bias and the weaker oscillation in some CMIP5 GCMs, the frequency of PVO events is significantly underestimated by CMIP5 GCMs; while in most ESMs, it is comparable to that in reanalysis. The PVO events in reanalysis （except in 20CR） mainly occur from mid-winter to early spring （January-March）; but in some of the CMIP5 models, a l-2 month delay exists, especially in most of the CMIP5 GCMs. The long-term trend of the PVO time series does not correspond to long-term changes in the frequency of PVO events in most of the CMIP5 models.展开更多
This study uses the coupled atmosphere–surface climate feedback–response analysis method（CFRAM） to analyze the surface temperature biases in the Flexible Global Ocean–Atmosphere–Land System model, spectral versi...This study uses the coupled atmosphere–surface climate feedback–response analysis method（CFRAM） to analyze the surface temperature biases in the Flexible Global Ocean–Atmosphere–Land System model, spectral version 2（FGOALS-s2）in January and July. The process-based decomposition of the surface temperature biases, defined as the difference between the model and ERA-Interim during 1979–2005, enables us to attribute the model surface temperature biases to individual radiative processes including ozone, water vapor, cloud, and surface albedo; and non-radiative processes including surface sensible and latent heat fluxes, and dynamic processes at the surface and in the atmosphere. The results show that significant model surface temperature biases are almost globally present, are generally larger over land than over oceans, and are relatively larger in summer than in winter. Relative to the model biases in non-radiative processes, which tend to dominate the surface temperature biases in most parts of the world, biases in radiative processes are much smaller, except in the sub-polar Antarctic region where the cold biases from the much overestimated surface albedo are compensated for by the warm biases from nonradiative processes. The larger biases in non-radiative processes mainly lie in surface heat fluxes and in surface dynamics,which are twice as large in the Southern Hemisphere as in the Northern Hemisphere and always tend to compensate for each other. In particular, the upward/downward heat fluxes are systematically underestimated/overestimated in most parts of the world, and are mainly compensated for by surface dynamic processes including the increased heat storage in deep oceans across the globe.展开更多
This paper summarizes the results of the researches on the middle and upper atmosphere obtained by Chinese scientists in 2008-2010.The focuses are specifically placed on the researches being associated with ground-bas...This paper summarizes the results of the researches on the middle and upper atmosphere obtained by Chinese scientists in 2008-2010.The focuses are specifically placed on the researches being associated with ground-based observation capability development,dynamical processes,the property of atmospheric circulation and the chemistry-climate coupling of the middle atmospheric layers.展开更多
In this report we summarize the research results by Chinese scientists in 2012–2014. The focuses are placed on the researches of the middle and upper atmosphere, specifically the researches related to ground-based ob...In this report we summarize the research results by Chinese scientists in 2012–2014. The focuses are placed on the researches of the middle and upper atmosphere, specifically the researches related to ground-based observation capability development, dynamical processes, the property of circulation and chemistry-climate coupling of the middle atmospheric layers.展开更多
In this report the research results by Chinese scientists in 2014—2016 are summarized.The focuses are placed on the researches of the middle and upper atmosphere,specifically the researches associated with ground-bas...In this report the research results by Chinese scientists in 2014—2016 are summarized.The focuses are placed on the researches of the middle and upper atmosphere,specifically the researches associated with ground-based observation capabihty development,dynamical processes,and properties of circulation and chemistry-climate coupling of the middle atmospheric layers.展开更多
This report reviews the researches for the middle and upper atmosphere in 2020-2022 by Chinese scientists.The report consists of five parts introducing primarily the results from the aspects of the development of infr...This report reviews the researches for the middle and upper atmosphere in 2020-2022 by Chinese scientists.The report consists of five parts introducing primarily the results from the aspects of the development of infrastructure,the structure and composition,the climate and modeling,the dynamics for the middle and upper atmosphere,and Coupling between Stratosphere and Troposphere,respectively.展开更多
The association of seasonal timing of stratospheric final warming events(SFWs) in spring and the occurrence of major and minor stratospheric sudden warming events(SSWs) in midwinter were investigated through statistic...The association of seasonal timing of stratospheric final warming events(SFWs) in spring and the occurrence of major and minor stratospheric sudden warming events(SSWs) in midwinter were investigated through statistical analysis, parallel comparison, and composite analysis, based on the NCEP-NCAR reanalysis dataset covering 1958–2012. It was found that the intensity and occurrence of winter SSW events can largely affect the timing of spring SFWs. Specifically, the SFW onset dates tend to be later(earlier) after the occurrence(absence) of winter major SSWs. However, the occurrence or absence of minor SSWs does not change the frequency of early and late SFWs. A parallel comparison of the temporal evolution of the anomalous circulation and planetary-waves between major SSW and minor SSW winters indicates that the stratospheric polar vortex(polar jet) will keep being anomalously stronger 30 days after major SSW onset. And the associated significant negative Eliassen-Palm(EP) flux anomalies can persist for as long as 45 days after major SSW events. In contrast, the circulation anomalies around the occurrence of minor SSW events can last only a few days. To further verify the possible influence of the occurrence of major SSWs on the seasonal timing of SFWs, composite analysis was performed respectively for the 21 major-SSW years, 15 minor-SSW years, and the 15 non-SSW years. Generally, planetary-wave activity in the extratropical stratosphere tends to be stronger(weaker) and the westerly polar jet is anomalously weaker(stronger) in major-SSW(non-SSW) winters. But in the following spring, the planetary-wave activity is weaker(stronger) accompanied with an anomalously stronger(weaker) stratospheric polar vortex. In spring after minor-SSW years, however, the stratospheric polar vortex and the westerly polar jet exhibit a state close to climatology with relatively gentle variations.展开更多
Based on the daily NCEP/DOE reanalysis II data,dates of the boreal spring Stratospheric Final Warming(SFW) events during 1979–2010 are defined as the time when the zonal-mean zonal wind at the central latitudes(65...Based on the daily NCEP/DOE reanalysis II data,dates of the boreal spring Stratospheric Final Warming(SFW) events during 1979–2010 are defined as the time when the zonal-mean zonal wind at the central latitudes(65°–75°N) of the westerly polar jet drops below zero and never recovers until the subsequent autumn.It is found that the SFW events occur successively from the mid to the lower stratosphere and averagely from the mid to late April with a temporal lag of about 13 days from 10 to 50 hPa.Over the past 32 years,the earliest SFW occurs in mid March whereas the latest SFW happens in late May,showing a clear interannual variability of the time of SFW.Accompanying the SFW onset,the stratospheric circulation transits from a winter dynamical regime to a summertime state,and the maximum negative tendency of zonal wind and the strongest convergence of planetary-wave are observed.Composite results show that the early/late SFW events in boreal spring correspond to a quicker/slower transition of the stratospheric circulation,with the zonal-mean zonal wind reducing about 20/5 m s-1 at 30 hPa within 10 days around the onset date.Meanwhile,the planetary wave activities are relatively strong/weak associating with an out-of-/in-phase circumpolar circulation anomaly before and after the SFW events in the stratosphere.All these results indicate that,the earlier breakdown of the stratospheric polar vortex(SPV),as for the winter stratospheric sudden warming(SSW) events is driven mainly by wave forcing;and in contrast,the later breakdown of the SPV exhibits more characteristics of its seasonal evolution.Nevertheless,after the breakdown of SPV,the polar temperature anomalies always exhibit an out-of-phase relationship between the stratosphere and the troposphere for both the early and late SFW events,which implies an intimate stratosphere–troposphere dynamical coupling in spring.In addition,there exists a remarkable interdecadal change of the onset time of SFW in the mid 1990s.On average,the SFW onset time before the mid 1990s is 11 days earlier than that afterwards,corresponding to the increased/decreased planetary wave activities in late winter-early spring before/after the 1990s.展开更多
文摘夏季亚洲季风区是对流层向平流层物质输送的主要通道,其对平流层水汽的变化有重要贡献。以往的研究表明亚洲季风区向平流层的水汽传输主要在青藏高原及周边地区。本文利用多年平均的逐日ERAi、MERRA再分析数据和微波临边观测仪(Microwave Limb Sounder,MLS)数据,首先对比分析夏季青藏高原周边上空水汽的分布特征,再利用再分析资料分析了对流层—平流层水汽传输的特征。结果表明:青藏高原周边特定的等熵面和对流层顶结构分布有利于水汽向平流层的绝热输送;在南亚高压的东北侧,从青藏高原到中太平洋地区,340～360 K层次存在最为显著的水汽向平流层的纬向等熵绝热输送通道,7～8月平均输送强度可达约7×103 kg s-1。此外,在伊朗高原及南亚高压的西部,350～360 K层次也存在一支水汽向平流层的经向等熵绝热输送通道,但强度相对较弱(约2.5×103kgs-1)。在青藏高原南侧370～380K层次存在强的水汽向平流层的非绝热输送,主要由深对流和大尺度上升运动引起,7～8月平均输送强度约0.4×103 kg s-1。落基山以东到大西洋西部,350～360 K层次存在水汽向平流层的纬向等熵绝热输送通道,但强度也弱得多(约2.5×103 kg s-1)。
文摘本文利用逐年7~8月平均的ERA-Interim再分析资料并结合SWOOSH(Stratospheric water and ozone satellite homogenized)水汽数据,分析了青藏高原及周边地区330~360 K层次水汽质量分布的年际异常特征及其成因。结果表明,水汽质量分布异常表现为整体异常型、东西偶极异常型和南北偶极异常型三个主导分布型。整体异常型在水汽质量整体偏多时,青藏高原地区对流和垂直向上的水汽质量非绝热传输偏强,上对流层为异常偏强的水汽质量非绝热辐合;此时对应南亚高压偏强,青藏高原地区上对流层的水汽质量绝热辐散和高原以西地区的水汽质量绝热辐合都异常偏强,水汽质量整体偏少时则相反。东西偶极异常型水汽质量呈西多/东少分布时,青藏高原西部(中东部)对流和垂直向上的水汽质量非绝热传输异常偏强(弱),上对流层的水汽质量非绝热辐合和水汽质量绝热辐散也异常偏强(偏弱);同时对应南亚高压偏西,青藏高原以西到伊朗高原的上对流层有异常的自东向西的水汽质量绝热输送和水汽质量绝热辐合。水汽质量呈西少/东多分布时则有相反的结果。南北偶极异常型水汽质量呈北多/南少分布时,对应南亚高压偏北,青藏高原北部的上对流层有异常自南向北的水汽质量绝热输送所造成的水汽质量辐合,同时该地区低层异常偏强的自下向上的水汽质量非绝热输送也加强水汽质量辐合,而青藏高原南侧上对流层则为异常偏弱的水汽质量绝热辐散和水汽质量非绝热辐合,水汽质量呈北少/南多分布时相反。
基金supported by the National Basic Research Program of China (Grant Nos. 2010CB950400 and 2010CB428603)the World Climate Research Program’s Working Group responsible for the Coupled Model Intercomparison Project
文摘A parallel comparison is made of the circulation climatology and the leading oscillation mode of the northern winter stratosphere among six reanalysis products and 24 CMIP5 （Coupled Model Intercomparison Project Phase 5） models. The results reveal that the NCEP/NCAR, NECP/DOE, ERA40, ERA-Interim and JRA25 reanalyses are quite consistent in describ- ing the climatology and annual cycle of the stratospheric circulation. The 20CR reanalysis, however, exhibits a remarkable ＂cold pole＂ bias accompanied by a much stronger stratospheric polar jet, similar as in some CMIP5 models. Compared to the 1-2 month seasonal drift in most coupled general circulation models （GCMs）, the seasonal cycle of the stratospheric zonal wind in most earth system models （ESMs） agrees very well with reanalysis. Similar to the climatology, the amplitude of Polar Vortex Oscillation （PVO） events also varies among CMIP5 models. The P^O amplitude in most GCMs is relatively weaker than in reanalysis, while that in most of the ESMs is more realistic. In relation to the ＂cold pole＂ bias and the weaker oscillation in some CMIP5 GCMs, the frequency of PVO events is significantly underestimated by CMIP5 GCMs; while in most ESMs, it is comparable to that in reanalysis. The PVO events in reanalysis （except in 20CR） mainly occur from mid-winter to early spring （January-March）; but in some of the CMIP5 models, a l-2 month delay exists, especially in most of the CMIP5 GCMs. The long-term trend of the PVO time series does not correspond to long-term changes in the frequency of PVO events in most of the CMIP5 models.
基金jointly supported by projects XDA11010402 GYHY201406001the National Basic Key Project (973) 2010CB428603 and 2010CB950400
文摘This study uses the coupled atmosphere–surface climate feedback–response analysis method（CFRAM） to analyze the surface temperature biases in the Flexible Global Ocean–Atmosphere–Land System model, spectral version 2（FGOALS-s2）in January and July. The process-based decomposition of the surface temperature biases, defined as the difference between the model and ERA-Interim during 1979–2005, enables us to attribute the model surface temperature biases to individual radiative processes including ozone, water vapor, cloud, and surface albedo; and non-radiative processes including surface sensible and latent heat fluxes, and dynamic processes at the surface and in the atmosphere. The results show that significant model surface temperature biases are almost globally present, are generally larger over land than over oceans, and are relatively larger in summer than in winter. Relative to the model biases in non-radiative processes, which tend to dominate the surface temperature biases in most parts of the world, biases in radiative processes are much smaller, except in the sub-polar Antarctic region where the cold biases from the much overestimated surface albedo are compensated for by the warm biases from nonradiative processes. The larger biases in non-radiative processes mainly lie in surface heat fluxes and in surface dynamics,which are twice as large in the Southern Hemisphere as in the Northern Hemisphere and always tend to compensate for each other. In particular, the upward/downward heat fluxes are systematically underestimated/overestimated in most parts of the world, and are mainly compensated for by surface dynamic processes including the increased heat storage in deep oceans across the globe.
基金Supported by the National Natural Sciences Foundation of China under grant (40830102,40333034)the Knowledge Innovation Project of Chinese Academy of Sciences under Grant (KZCX2-YW-123)
文摘This paper summarizes the results of the researches on the middle and upper atmosphere obtained by Chinese scientists in 2008-2010.The focuses are specifically placed on the researches being associated with ground-based observation capability development,dynamical processes,the property of atmospheric circulation and the chemistry-climate coupling of the middle atmospheric layers.
文摘In this report we summarize the research results by Chinese scientists in 2012–2014. The focuses are placed on the researches of the middle and upper atmosphere, specifically the researches related to ground-based observation capability development, dynamical processes, the property of circulation and chemistry-climate coupling of the middle atmospheric layers.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences [grant number XDA17010105-02]Key Research Program of Frontier Sciences,CAS [grant number QYZDY-SSW-DQC018]the National Natural Science Foundation of China [grant numbers91437105,41430533,and 41575041]
文摘In this report the research results by Chinese scientists in 2014—2016 are summarized.The focuses are placed on the researches of the middle and upper atmosphere,specifically the researches associated with ground-based observation capabihty development,dynamical processes,and properties of circulation and chemistry-climate coupling of the middle atmospheric layers.
文摘This report reviews the researches for the middle and upper atmosphere in 2020-2022 by Chinese scientists.The report consists of five parts introducing primarily the results from the aspects of the development of infrastructure,the structure and composition,the climate and modeling,the dynamics for the middle and upper atmosphere,and Coupling between Stratosphere and Troposphere,respectively.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences [grant number XDA17010105]the National Natural Science Foundation of China [grant numbers 91437105,41430533,and 41575041]the Key Research Program of Frontier Sciences [grant number QYZDY-SSW-DQC018]
基金supported by the National Basic Research Program of China(Grant No.2010CB428603)Advanced Talent Program of NUIST(Grant No.2014R010)
文摘The association of seasonal timing of stratospheric final warming events(SFWs) in spring and the occurrence of major and minor stratospheric sudden warming events(SSWs) in midwinter were investigated through statistical analysis, parallel comparison, and composite analysis, based on the NCEP-NCAR reanalysis dataset covering 1958–2012. It was found that the intensity and occurrence of winter SSW events can largely affect the timing of spring SFWs. Specifically, the SFW onset dates tend to be later(earlier) after the occurrence(absence) of winter major SSWs. However, the occurrence or absence of minor SSWs does not change the frequency of early and late SFWs. A parallel comparison of the temporal evolution of the anomalous circulation and planetary-waves between major SSW and minor SSW winters indicates that the stratospheric polar vortex(polar jet) will keep being anomalously stronger 30 days after major SSW onset. And the associated significant negative Eliassen-Palm(EP) flux anomalies can persist for as long as 45 days after major SSW events. In contrast, the circulation anomalies around the occurrence of minor SSW events can last only a few days. To further verify the possible influence of the occurrence of major SSWs on the seasonal timing of SFWs, composite analysis was performed respectively for the 21 major-SSW years, 15 minor-SSW years, and the 15 non-SSW years. Generally, planetary-wave activity in the extratropical stratosphere tends to be stronger(weaker) and the westerly polar jet is anomalously weaker(stronger) in major-SSW(non-SSW) winters. But in the following spring, the planetary-wave activity is weaker(stronger) accompanied with an anomalously stronger(weaker) stratospheric polar vortex. In spring after minor-SSW years, however, the stratospheric polar vortex and the westerly polar jet exhibit a state close to climatology with relatively gentle variations.
基金supported by the National Basic Research Program of China(Grant Nos.2010CB428603 and 2010CB950400)National Natural Science Foundation of China(Grant No.41275094)
文摘Based on the daily NCEP/DOE reanalysis II data,dates of the boreal spring Stratospheric Final Warming(SFW) events during 1979–2010 are defined as the time when the zonal-mean zonal wind at the central latitudes(65°–75°N) of the westerly polar jet drops below zero and never recovers until the subsequent autumn.It is found that the SFW events occur successively from the mid to the lower stratosphere and averagely from the mid to late April with a temporal lag of about 13 days from 10 to 50 hPa.Over the past 32 years,the earliest SFW occurs in mid March whereas the latest SFW happens in late May,showing a clear interannual variability of the time of SFW.Accompanying the SFW onset,the stratospheric circulation transits from a winter dynamical regime to a summertime state,and the maximum negative tendency of zonal wind and the strongest convergence of planetary-wave are observed.Composite results show that the early/late SFW events in boreal spring correspond to a quicker/slower transition of the stratospheric circulation,with the zonal-mean zonal wind reducing about 20/5 m s-1 at 30 hPa within 10 days around the onset date.Meanwhile,the planetary wave activities are relatively strong/weak associating with an out-of-/in-phase circumpolar circulation anomaly before and after the SFW events in the stratosphere.All these results indicate that,the earlier breakdown of the stratospheric polar vortex(SPV),as for the winter stratospheric sudden warming(SSW) events is driven mainly by wave forcing;and in contrast,the later breakdown of the SPV exhibits more characteristics of its seasonal evolution.Nevertheless,after the breakdown of SPV,the polar temperature anomalies always exhibit an out-of-phase relationship between the stratosphere and the troposphere for both the early and late SFW events,which implies an intimate stratosphere–troposphere dynamical coupling in spring.In addition,there exists a remarkable interdecadal change of the onset time of SFW in the mid 1990s.On average,the SFW onset time before the mid 1990s is 11 days earlier than that afterwards,corresponding to the increased/decreased planetary wave activities in late winter-early spring before/after the 1990s.
