利用美国大气研究中心(the National Center for Atmospheric Research,NCAR)的中层大气模式模拟了平流层准两年振荡(Quasi-Biennial Oscillation,QBO)过程对对流层顶和对流层上层的影响,并结合NCEP(the National Centers for Environme...利用美国大气研究中心(the National Center for Atmospheric Research,NCAR)的中层大气模式模拟了平流层准两年振荡(Quasi-Biennial Oscillation,QBO)过程对对流层顶和对流层上层的影响,并结合NCEP(the National Centers for Environmental Prediction)/NCAR、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)月平均的风场资料和实际的探空观测资料,分析了平流层QBO对南海夏季风的影响作用.结果表明:平流层QBO会引起平流层的异常经向环流并向下传播,在QBO位相的中后期和位相转换期影响到对流层顶和对流层上层,使热带和低纬度的对流层上层形成异常的经向气压梯度,最终在夏季的对流层热带地区激发出不同类型的异常环流—西风位相时,激发出与南海夏季风环流相反的异常环流,在南海地区有显著的异常下沉运动,对南海夏季风有削弱作用;东风位相时,激发出反Hadley环流型的异常环流,在南海地区有明显的异常上升气流,对南海夏季风有加强的效果.虽然QBO对南海夏季风经向环流有影响,但它并不是决定南海夏季风准两年变化的唯一因子.展开更多
美国西北研究机构(NWRA:NorthWest Research Associates)发布了1963-1992年期间在Kwajalein岛礁(8°N,167°E)上共计1862次火箭探测的平流层风场和温度剖面.本文选取测量较为连续的1969-1972年期间共计345个风场剖面来研...美国西北研究机构(NWRA:NorthWest Research Associates)发布了1963-1992年期间在Kwajalein岛礁(8°N,167°E)上共计1862次火箭探测的平流层风场和温度剖面.本文选取测量较为连续的1969-1972年期间共计345个风场剖面来研究平流层月平均风场及其两年变化、年变化和半年变化的特征.同时与目前应用较为广泛的风场模式HWM07(Horizontal Wind Model:2007)和CIRA86(COSPAR International Reference Atmosphere:1986)进行了比较.火箭测量的4年逐月平均纬向风在夏季为西向风,并在8月41km处达到最大值45ms-1;在冬季变为东向风,并在3月57km处达到最大值47ms-1.全年的经向风在60km以下基本上是北向风且风速低于10ms-1.纬向风在20~35km之间以两年变化为主,振幅在10~17ms-1之间;在45~55km之间以半年变化为主,振幅是16~25 ms-1之间;在5km以上以年变化为主,振幅在16~25 ms-1之间.测量风场与HMW07相比,HWM07的西向风在7月46km处达到最大值38ms-1,东向风在2月60km处达到最大值37ms-1,均小于测量风场的峰值.测量风场与CIRA86相比,CIRA86的西向风在7月49km处达到最大值36ms-1,东向风在3月60km处达到最大值43ms-1,仍小于测量风场的峰值.测量风速稍大于模式风速的可能原因之一是测量风场包含了背景风场和各种波动成分,而模式风场是气候学平均的结果;此外,HWM07和CIRA86虽然包含了不少探空火箭数据,但并没有包含在Kwajalein岛礁的测量资料.展开更多
The National Centers for Environmental Prediction (NCEP) reanalysis data, Climate Diagnostics Center Merged Analysis of Precipitation (CMAP) results, and NOAA Extended Reconstructed Sea Surface Temperature (SST), have...The National Centers for Environmental Prediction (NCEP) reanalysis data, Climate Diagnostics Center Merged Analysis of Precipitation (CMAP) results, and NOAA Extended Reconstructed Sea Surface Temperature (SST), have been utilized in this paper to study the quasi-biennial variations in Asia-Pacific monsoon subsystems and associated SST anomalies (SSTA) and wind anomalies. Four monsoon indices are computed from NCEP/ National Center for Atmospheric Research (NCAR) reanalysis to represent the South Asian monsoon (SAM), South China Sea summer monsoon (SCSSM), Western North Pacific monsoon (WNPM) and East Asian monsoon (EAM), respectively. The quasi-biennial periods are very significant in Asia-Pacific monsoons (as discovered by power spectrum analysis), and for SAM and EAM---with moderate effects by El Ni?o-Southern Oscillation (ENSO)---the quasi-biennial periods are the most important factor. For SCSSM and WNPM (once again due to the effects of ENSO), the quasi-biennial periods are of secondary durations. There are obvious interdecadal variations in the quasi-biennial modes of the Asia-Pacific monsoon, so in the negative phase the biennial modes will not be significant or outstanding. The wind anomalies and SSTA associated with the biennial modes are very different in the SAM, WNPM and EAM regions. Since the WNPM and SCSSM are very similar in the biennial modes, they can be combined into one subsystem, called SCS/WNPM.展开更多
文摘利用美国大气研究中心(the National Center for Atmospheric Research,NCAR)的中层大气模式模拟了平流层准两年振荡(Quasi-Biennial Oscillation,QBO)过程对对流层顶和对流层上层的影响,并结合NCEP(the National Centers for Environmental Prediction)/NCAR、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)月平均的风场资料和实际的探空观测资料,分析了平流层QBO对南海夏季风的影响作用.结果表明:平流层QBO会引起平流层的异常经向环流并向下传播,在QBO位相的中后期和位相转换期影响到对流层顶和对流层上层,使热带和低纬度的对流层上层形成异常的经向气压梯度,最终在夏季的对流层热带地区激发出不同类型的异常环流—西风位相时,激发出与南海夏季风环流相反的异常环流,在南海地区有显著的异常下沉运动,对南海夏季风有削弱作用;东风位相时,激发出反Hadley环流型的异常环流,在南海地区有明显的异常上升气流,对南海夏季风有加强的效果.虽然QBO对南海夏季风经向环流有影响,但它并不是决定南海夏季风准两年变化的唯一因子.
文摘美国西北研究机构(NWRA:NorthWest Research Associates)发布了1963-1992年期间在Kwajalein岛礁(8°N,167°E)上共计1862次火箭探测的平流层风场和温度剖面.本文选取测量较为连续的1969-1972年期间共计345个风场剖面来研究平流层月平均风场及其两年变化、年变化和半年变化的特征.同时与目前应用较为广泛的风场模式HWM07(Horizontal Wind Model:2007)和CIRA86(COSPAR International Reference Atmosphere:1986)进行了比较.火箭测量的4年逐月平均纬向风在夏季为西向风,并在8月41km处达到最大值45ms-1;在冬季变为东向风,并在3月57km处达到最大值47ms-1.全年的经向风在60km以下基本上是北向风且风速低于10ms-1.纬向风在20~35km之间以两年变化为主,振幅在10~17ms-1之间;在45~55km之间以半年变化为主,振幅是16~25 ms-1之间;在5km以上以年变化为主,振幅在16~25 ms-1之间.测量风场与HMW07相比,HWM07的西向风在7月46km处达到最大值38ms-1,东向风在2月60km处达到最大值37ms-1,均小于测量风场的峰值.测量风场与CIRA86相比,CIRA86的西向风在7月49km处达到最大值36ms-1,东向风在3月60km处达到最大值43ms-1,仍小于测量风场的峰值.测量风速稍大于模式风速的可能原因之一是测量风场包含了背景风场和各种波动成分,而模式风场是气候学平均的结果;此外,HWM07和CIRA86虽然包含了不少探空火箭数据,但并没有包含在Kwajalein岛礁的测量资料.
基金National Natural Science Foundation of China (40505019)
文摘The National Centers for Environmental Prediction (NCEP) reanalysis data, Climate Diagnostics Center Merged Analysis of Precipitation (CMAP) results, and NOAA Extended Reconstructed Sea Surface Temperature (SST), have been utilized in this paper to study the quasi-biennial variations in Asia-Pacific monsoon subsystems and associated SST anomalies (SSTA) and wind anomalies. Four monsoon indices are computed from NCEP/ National Center for Atmospheric Research (NCAR) reanalysis to represent the South Asian monsoon (SAM), South China Sea summer monsoon (SCSSM), Western North Pacific monsoon (WNPM) and East Asian monsoon (EAM), respectively. The quasi-biennial periods are very significant in Asia-Pacific monsoons (as discovered by power spectrum analysis), and for SAM and EAM---with moderate effects by El Ni?o-Southern Oscillation (ENSO)---the quasi-biennial periods are the most important factor. For SCSSM and WNPM (once again due to the effects of ENSO), the quasi-biennial periods are of secondary durations. There are obvious interdecadal variations in the quasi-biennial modes of the Asia-Pacific monsoon, so in the negative phase the biennial modes will not be significant or outstanding. The wind anomalies and SSTA associated with the biennial modes are very different in the SAM, WNPM and EAM regions. Since the WNPM and SCSSM are very similar in the biennial modes, they can be combined into one subsystem, called SCS/WNPM.
基金funded by the National Natural Science Foundation of China[grant number 41776031]the Guangdong Natural Science Foundation[grant number 2015A030313796]+3 种基金the National Program on Global Change and Air-Sea Interaction[grant number GASI-IPOVAI-04]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010104]the program for scientific research start-upfunds of Guangdong Ocean Universitythe Foundation for Returned Scholars of the Ministry of Education of China