摘要
利用1979—2014年ERA-Interim逐月的风场、海平面气压场和位势高度场等再分析资料以及中国160站降水观测资料,采用回归分析等方法分析了盛夏(7、8月)南海(South China Sea,SCS)低空越赤道气流(Cross-Equatorial Flow,CEF)的变化及其与东亚夏季风的联系,结果表明:盛夏南海低空越赤道气流(SCEF)强度指数与南海夏季风强度指数呈显著的正相关关系,与东亚副热带夏季风强度指数呈显著的负相关关系。当盛夏SCEF偏强(弱)时,亚洲热带低压及西太平洋赤道辐合带增强(减弱),西太平洋副热带高压强度减弱(增强)、东撤(西伸),南海北部和西北太平洋地区为明显的气旋式(反气旋式)环流异常,使得南海夏季风增强(减弱)和东亚副热带夏季风减弱(增强)。此外,当盛夏SCEF偏强时,由于东亚副热带夏季风减弱,我国华南地区为东北风异常,华北地区为偏南风异常,受其影响,我国华南地区为显著的水汽辐合区,华中地区为显著的水汽辐散区,使得盛夏华南地区降水增多,华中地区降水减少;反之亦然。
Based on the monthly European Center for Medium-Range Weather Forecasts(ECMWF)Re-Analysis(ERA)Interim data and the observed precipitation data of 160 stations in China for the period 1979-2014,the variation of the Cross-Equatorial Flow(CEF)over the South China Sea(SCS)and its connection with the East Asian summer monsoon in midsummer are investigated by regression analysis method.It is shown that the index of the intensity of the SCS low-level CEF(SCEF)has a significantly positive(negative)correlation with the SCS summer monsoon index(East Asian subtropical summer monsoon index).When the SCEF in midsummer is stronger(weaker),the intensity of Asia low pressure and Inter-tropical Convergence Zone(ITCZ)in the west Pacific increases(decreases),the west Pacific subtropical high becomes weaker(stronger)and moves eastward(westward),cyclonic(anti-cyclonic)circulation anomalies emerge in the northern area of SCS and Northwest Pacific,resulting in the strengthening(weakening)of the SCS summer monsoon and the weakening(strengthening)of the East Asian subtropical summer monsoon.Moreover,when the SCEF is stronger,there is northeast(southerly)wind anomaly in South China(North China)induced by the weakening of the East Asian subtropical summer monsoon.As a result,water vapor anomaly is converged(diverged)in South China(Central China),leading to more(less)precipitation in South China(Central China);and vice versa.
作者
李忠贤
范倩莹
曾刚
邓伟涛
LI Zhong-xian;FAN Qian-ying;ZENG Gang;DENG Wei-tao(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanj)
出处
《热带气象学报》
CSCD
北大核心
2018年第3期339-346,共8页
Journal of Tropical Meteorology
基金
国家自然科学基金资助项目(41575102
41575085)
国家重点基础研究发展计划(973计划)项目(2013CB430202)共同资助
关键词
气候学
东亚夏季风
回归分析
南海越赤道气流
盛夏
中国降水
climatology
East Asian summer monsoon
Cross-Equatorial Flow over the South China Sea
midsummer
precipitation in China
