中国西北东部汛期降水主模态的年代际差异及其大气环流特征  

Interdecadal Difference of Dominant Modes of Precipitation in Rainy Season over the Eastern Part of Northwest China and Their Corresponding Atmospheric Circulation Characteristics

作　　者：马金龙 庞雪琪 杨建玲[1,2,5] 

机构地区：[1]中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室,宁夏银川750002 [2]宁夏气象防灾减灾重点实验室,宁夏银川750002 [3]银川市气象局,宁夏银川750002 [4]山西省大气探测技术保障中心,山西太原030002 [5]宁夏回族自治区气候中心,宁夏银川750002

出　　处：《干旱气象》2017年第6期940-948,共9页Journal of Arid 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);2014年江苏省普通高校研究生科研创新计划项目(KYLX_0830)共同资助

摘　　要：利用1961—2012年中国西北东部156站降水和NCEP/NCAR再分析资料,分析该地区汛期(5—9月)降水特征的变化,构造综合相似指数,将历年汛期降水量场划分为全区一致偏多型、一致偏少型、南多北少型、南少北多型共4类降水类型,其中以全区一致偏少型所占比例最多。在全球气候变暖背景下,全区降水虽仍以一致偏少型为主,但其比例明显减小,而全区一致偏多型比例明显增加。全区一致偏多(少)的降水异常敏感区的中心位置随时间逐渐向东南方向移动,而南多(少)北少(多)型的降水异常敏感区中心位置则随时间逐渐向西北方向移动,两个模态所反映的降水异常敏感区的范围和强度在各年代均有较大差异。夏季西部型南亚高压、乌拉尔山脊显著增强,蒙古气旋加强、西太平洋副热带高压加强,南海、孟加拉湾的暖湿气流深入到中国西北东部地区,是西北东部降水一致偏多的主要大气环流特征。Based on the rainfall data at 156 meteorological stations in the eastern part of Northwest China and the NCEP/NCAR reanalysis dataset during 1961-2012,the variation features of precipitation in flood season( May-September) were investigated. According to the synthetic similarity index constructed in this paper,the precipitation fields in flood season over the years were divided into four patterns including the regional consistent more than normal,the regional consistent less than normal,the more in the south and less in the north,the less in the south and more in the north. Among the four patterns,the regional consistent less than normal pattern took the largest proportion. Under the global warming,although the pattern of regional consistent less than normal was dominated in the whole region,its percentage decreased,while that for the pattern of regional consistent more than normal increased distinctly. The central positions of the sensitive districts for the pattern of regional consistent more( less) than normal shifted to southeast over time,but for the pattern of the south more( less) and the north less( more),the central positions moved to northwest. The ranges and intensities of the rainfall anomaly regions responding to the two modes varied in different decades. For this pattern,the atmosphere circulation characteristic in summer could be depicted as the western south Asian high,the Ural ridge,the Mongolia cyclone and the western Pacific subtropical high enhancing significantly,so the warm and moist air from the South China Sea and the Bay of Bengal was transported into the eastern part of Northwest China.

关 键 词：中国西北东部 汛期降水 大气环流 

分 类 号：P426.614[天文地球—大气科学及气象学]