中国西北地区东部盛夏降水特征及对初春地表感热异常的响应  

Response of Summer Precipitation in Eastern Part of Northwest China to the Surface Sensible Heat in Early Spring

作　　者：王蕊 王慧 李栋梁 WANG Rui;WANG Hui;LI Dongliang(Collatborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Key Laboratory of Meteorological Disaster,Ministry of Education,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]南京信息工程大学大气科学学院/气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室

出　　处：《高原气象》2019年第6期1241-1250,共10页Plateau Meteorology

基　　金：中国气象局预报员专项(CMAYBY2019-119);公益性行业(气象)科研专项[GYHY(QX)201306027];江苏省基础研究计划自然科学青年基金项目(BK20130997)

摘　　要：选用1961-2015年中国西北地区74个气象站逐月地表感热通量计算资料,及其东部155个常规气象站夏季的月降水资料以及NCEP/NCAR月平均再分析资料,通过经验正交函数分解(EOF)、线性回归分析、奇异值分解(SVD)等数理统计分析方法,分析了西北地区东部盛夏(7-8月)降水的时空异常演变特征及其与西北地区初春(3-4月)地表感热异常的联系及成因。结果表明:(1)中国西北地区东部盛夏降水由东南向西北递减,总体呈年代际减少趋势,减少最明显的区域为宁夏北部、内蒙古中南部。其空间异常型主要表现为全区一致的增多(减少)和西北-东南向"-+-"变化。(2)当西北地区初春(3-4月)地表感热通量整体异常偏强(弱)时,盛夏(7-8月),在贝加尔湖以南、中国北方的上空出现高度场异常偏高(低),中国西北地区水汽辐散(辐合)加强,西北地区东部宁夏平原降水出现异常偏少(偏多);而陕西南部有水汽的辐合(辐散)加强,有(不)利于该地区降水的产生。The monthly sensible heat flux calculation data of 74 conventional meteorological stations in Northwestern China,the monthly precipitation data of 155 conventional meteorological stations in the northwest of China,and the monthly average reanalysis data of NCEP/NCAR from 1961 to 2015 were selected. Mathematical statistical analysis methods such as empirical orthogonal function decomposition( EOF),linear regression analysis,and singular value decomposition( SVD) were used to analyze relationship between the anomalous temporal and spatial evolution characteristics of precipitation in midsummer( July-August) in the eastern part of Northwest China and the surface sensible heat anomalies in the early spring( March-April) of the Northwestern China. The results show that:( 1) The precipitation in the eastern part of Northwestern China decreases from southeast to northwest with an overall decadal decline. The most obvious areas for reduction are northern Ningxia and central and southern Inner Mongolia. Its spatial anomaly is mainly characterized by a consistent increase( decrease) in the whole region and a "-+-"change in the northwest-southeast direction.( 2) When the surface sensible heat flux is relatively strong( weak) in the early spring in Northwestern China,in midsummer( July-August),the height field over the southern part of Baikal Lake and northern China during midsummer is abnormally high( low),the water vapor divergence( convergence)in Northwestern China is strengthened,and the precipitation in the Ningxia Plain in the northwestern part of the northwest is abnormally low( above average);while in the southwest of Shaanxi,the convergence( diverging) of water vapor is strengthened,which is( not) conducive to the occurrence of precipitation in this region.

关 键 词：西北干旱区 西北地区东部 夏季降水 地表感热通量 气候变化 

分 类 号：P4[天文地球—大气科学及气象学]