热带气象学报2016，Vol.32Issue(6)：817-830,14.DOI:10.16032/j.issn.1004-4965.2016.06.004
东亚季风环流季节转变与亚太热力场之间的联系及其可能机理
RELATIONSHIP BETWEEN THE SEASONAL TRANSITION OF EAST ASIAN MONSOON CIRCULATION AND ASIA PACIFIC THERMAL FIELD AND POSSIBLE MECHANISMS
摘要
Abstract
The NCEP/NCAR reanalysis,CMAP rainfall and Hadley Centre SST datasets are used to investigate the relationship between the seasonal transition of East Asian monsoon and Asia Pacific thermal contrast and as sociated possible causes.Based on the 250 hPa air temperature over two selected key areas,the Asia-Pacific thermal difference (APTD) index is calculated.Results show that the APTD index is highly consistent with Asia-Pacific Oscillation (APO) index,which is defined by Zhao et al.in term of different key areas in different seasons.Moreover,the APTD index can be well used to determine the time point of the seasonal transition in association with the Asia Pacific thermal contrast.It is found that the time of seasonal transition determined by the APTD index can represent the seasonal change in East Asian atmospheric circulation from winter to summer.The transition characteristic of the circulation can be summarized as follows.The continental cold high at lower tropospheric level moves eastward to the East China Sea and decreases rapidly in intensity,while the low-level northerly winds turn to be southerly winds.At mid tropospheric level,the East Asia major trough is reduced and moves eastward.Furthermore,the subtropical high strengthens and appears in the vicinity of Philippines.The South Asia high shifts from the east of Philippines to the west of Indochina Peninsula,together with the prevailing northerly into southerly at upper tropospheric level.Meanwhile,the westerly and easterly jets both jump to the north.The seasonal transition of atmospheric circulation is closely related to the thermal contrast,and the possible mechanism can be concluded as follows.Under the background of the APTD seasonal transition,the southerly wind appears firstly at low level,which triggers the ascending motion via changing vertical shear of meridional winds.The resultant latent heating accelerates the transition of heating pattern from winter to summer.The summer heating pattern can further promote the adjustment of circulation,which favors the formation and strengthening of the low-level southerly and upper-level northerly winds.As a result,the meridional circulation of the East Asian subtropical monsoon is established through a positive feedback between the circulation and thermal fields.Moreover,it is concluded that this time point of this seasonal transition have a significant positive correlation with the sea surface temperature anomalies over the tropical central-eastern Pacific Ocean,providing a basis for the short-term climate prediction.关键词
东亚季风/季节转变/亚洲-太平洋涛动/可能机理Key words
East Asia monsoon/seasonal transition/Asia-Pacific Oscillation (APO)/possible mechanism分类
天文与地球科学引用本文复制引用
黄娇文,何金海,徐海明,金啟华..东亚季风环流季节转变与亚太热力场之间的联系及其可能机理[J].热带气象学报,2016,32(6):817-830,14.基金项目
国家自然科学基金(41375089、41490643、41575077) （41375089、41490643、41575077）
国家重点基础研究发展计划973项目(2013CB430202) （2013CB430202）
公共性行业专项(GYHY201406018) （GYHY201406018）
江苏省“333”工程(BRA2015290) （BRA2015290）
江苏高校优势学科建设工程项目(PAPD) （PAPD）
长江学者和创新团队发展计划(PCSIRT) （PCSIRT）
江苏省青蓝工程创新团队项目共同资助 （）
