欧亚中高纬冬季地表感热异常与中国西北东部夏季降水的可能联系  

Possible Linkage between Winter Surface Sensible Heat Flux Anomalies over the Mid-High Latitudes of the Eurasian Continent and Summer Precipitation in the Eastern Part of Northwest China

作　　者：庞雪琪 李栋梁[1] 姚慧茹[1] 

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,南京210044

出　　处：《高原气象》2017年第3期675-684,共10页Plateau Meteorology

基　　金：公益性行业(气象)科研专项(GYHY201306027;GYHY201506001-1);中国科学院寒旱区陆面过程与气候变化重点实验室开放基金项目(LPCC201503)

摘　　要：利用1979—2012年NCEP/DOE月平均地表感热通量再分析资料、西北东部156站夏季降水日资料,分析了欧亚大陆中高纬(61°N—67°N,53°E—68°E)冬季地表感热通量对我国西北东部夏季降水的影响。结果表明,当欧亚大陆中高纬冬季大气向地表输送感热值偏大时,春、夏季地表向大气输送感热值也偏大,引起了夏季500 hPa乌拉尔山阻塞高压加强,蒙古低压加深,西北太平洋副热带高压强度偏强,位置偏西,西风急流位置偏北,南亚高压呈东部型;对流层中低层表现为异常上升气流,同时有水汽的辐合,西北东部位于副高外围和蒙古低压底部,大气环流场的变化导致中国西北东部夏季降水偏多。当欧亚大陆中高纬冬季大气向地表输送感热值偏小时,春、夏季地表向大气输送感热值偏小,引起相反的夏季大气环流异常,使得中国西北东部夏季降水偏少。On the basis of daily precipitation observations at 156 stations from 1979 to 2012 in eastern part of Northwest China and the monthly means of surface sensible heat flux of NCEP/DOE reanalysis data,physical mechanism and possible linkage between winter surface sensible heat flux anomalies over mid-high latitudes of the Eurasian Continent（61°N—67°N,53°E—68°E） and summer precipitation over eastern part of Northwest China are analyzed in this study. The results show that when the sensible heat flux over mid-high latitudes of the Eurasian Continent transported from atmosphere to land surface is larger in winter,the sensible heat flux transportation from land surface to atmosphere will be larger in spring and summer as a consequence,the Ural blocking high and Mongolian low are strengthened,the northwest Pacific subtropical high is strengthened and migrating more west than normal,the subtropical westerly jet is anomalously northward and the South Asian high is far eastward,resulting in the ascending flow over eastern part of Northwest China strengthened. In addition,the transportation of the warm and moist air flows in low-level are strengthened in eastern part of Northwest China,as well as the water vapor convergence. All these contribute to the precipitation increasing over Eastern Part of Northwest China because of its location at the bottom of the Mongolian low and to the northwest of the subtropical high,in contrast,when the sensible heat flux transported from atmosphere to the surface is smaller in winter,the sensible heat flux transportation from land surface to atmosphere will also be smaller in spring and summer leading to the opposite atmospheric circulation anomalies in the summer,which will make the summer precipitation over the eastern part of Northwest China decreasing.

关 键 词：欧亚大陆中高纬 中国西北东部 地表感热通量 夏季降水 

分 类 号：P461[天文地球—大气科学及气象学]