伊朗高原和北非感热异常对夏季塔里木盆地降水的影响  

Effects of sensible heat anomalies in the Iranian Plateau and North Africa on summer precipitation in the Tarim Basin

作　　者：陈佳毅 赵勇[1] CHEN Jiayi;ZHAO Yong(Plateau Atmosphere&Environment Key Laboratory of Sichuan Province,School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,Sichuan,China)

机构地区：[1]高原大气与环境四川省重点实验室/成都信息工程大学大气科学学院,成都四川610225

出　　处：《干旱区地理》2022年第5期1357-1369,共13页Arid Land Geography

基　　金：国家自然科学基金(41875102);四川省科技计划项目(2020JDJQ0050)资助。

摘　　要：基于1971—2019年日本气象厅提供的JRA-55地表感热、大气环流再分析数据和国家气象信息中心提供的我国陆面逐月格点降水数据,研究了夏季伊朗高原和北非感热异常对同期塔里木盆地降水的可能影响。结果表明:(1)夏季伊朗高原感热和北非感热均与塔里木盆地夏季降水密切联系,将2个区域加热共同考虑,其与塔里木盆地降水的关系要比仅考虑单一区域加热更为紧密。(2)当伊朗高原感热整体偏强,且北非感热呈北弱南强异常分布时,对应中亚副热带西风急流相对偏南,中亚和蒙古高原上空分别为异常气旋和反气旋控制,塔里木盆地上空南风加强;热带印度洋水汽在阿拉伯海与中亚的异常环流配合下北上进入塔里木盆地;以上条件共同导致了同期塔里木盆地降水的增多,反之亦然。(3)北非和伊朗高原加热均可单独影响塔里木盆地夏季降水,其中伊朗高原感热对大尺度环流和水汽输送的影响均显著,因此其与降水的关系也更加密切。北非感热加热的影响主要体现在大尺度环流方面,对水汽输送的影响和伊朗高原存在差异,主要体现在印度半岛上空的异常反气旋位置偏南,导致阿拉伯海水汽无法进入塔里木盆地。Based on the JRA-55 surface sensible heat(SH)flux,Japan Meteorological Agency provided the reanalysis circulation data,and the National Meteorological Information Centre of China Meteorological Administration provided monthly grid precipitation data from 1971 to 2019.Therefore,the effects of SH anomalies over the Iranian Plateau and North Africa on precipitation in the Tarim Basin during summer were investigated.The results show that(1)the SH anomalies over both areas were closely associated with summer precipitation in the Tarim Basin,and the combined heating in the two regions was better associated with summer precipitation in the Tarim Basin than the heating in single one of the two regions.(2)When the SH strengthened in the Iranian Plateau,although strengthened and weakened in the southern and northern North Africa,respectively,it corresponded to the subtropical westerly jet in Central Asia shifting south,which caused an anomalous south wind to prevail in the Tarim Basin.Concurrently,an anomalous anticyclone over the Arabian Sea and that in Central Asia transported water vapor from the Arabian Sea to the Tarim Basin.Consequently,the abovementioned conditions contributed to more rainfall in the Tarim Basin during the same period.(3)Single thermal anomalies over the Iranian Plateau and North Africa can affect the summer precipitation in the Tarim Basin.Additionally,the SH over the Iranian Plateau can significantly influence the large-scale circulation and water vapor transport,indicating its closer relationship with precipitation.In contrast,SH anomalies in North Africa primarily affected the large-scale circulation,the impact on water vapor transport differed from that of the Iranian Plateau,and the more southerly positioning of the anomalous anticyclone over the Indian Peninsula,resulting in the inability to transport Arabian Sea water vapor into the Tarim Basin through the two-step processes.

关 键 词：感热异常 共同加热 北非 伊朗高原 塔里木盆地夏季降水 

分 类 号：P461[天文地球—大气科学及气象学]