陕西汛期降水时空分布及典型旱涝年环流特征  

Spatial and Temporal Distribution of Rainfall in Flood Season and Circulation Characteristics in Canonical Drought/Flood Years in Shaanxi Province

作　　者：肖科丽[1] 赵国令[2] 王越[1] 胡春娟[1] 

机构地区：[1]陕西省气象台 [2]陕西省气象局,西安710015

出　　处：《气象科技》2006年第4期410-414,共5页Meteorological Science and Technology

基　　金：陕西省气象台资助

摘　　要：根据陕西省1959～2002年汛期（6～9月）降水资料，采用旋转经验正交（REOF）分解方法，将陕西省按汛期降水划分为4个自然气候区：Ⅰ区包括关中及渭北地区，Ⅱ区为陕北长城沿线地区，Ⅲ区、Ⅳ区分别为陕南东部和陕南西部地区。对各气候区的降水变化特征进行分析，结果表明：汛期降水除陕南东部呈线性增加趋势外，其余各区均呈线性减少趋势。分析陕西省典型旱（涝）年北半球500hPa环流形势距平场和环流特征量发现：典型旱（涝）年，Nino3区海温为明显的正（负）距平；西太平洋副热带高压强度偏强（弱），脊线位置偏南（北）、西伸脊点偏东（西），欧亚地区西风环流指数偏弱（强），以经（纬）向环流为主。According to rainfall data from 1959 to 2002 in flood season （June to September） in Shaanxi, the province is divided into four natural climatic parts by REOF： Part Ⅰ includes Guanzhong and Weibei; Part Ⅱ is the area along the Great Wall in the northern Shaanxi; Parts Ⅲ and Ⅳ refer to the east and west parts of the southern Shaanxi Province respectively. The variation characteristics of rainfall in each region are also analyzed. Result shows that in the past 44 years, there appeared linear increase of rainfall only in the east part of the southern Shaanxi. In addition, the geopotential height anomaly fields on 500 hPa in the canonical drought （flood） years are also given through synthesizing analysis. Compared the circulation characteristic values between canonical drought and flood years, it is found out that in the canonical drought （flood） years, the anomaly of SST in Nino 3 is obviously positive （negative） ; the subtropical high on western Pacific is stronger （weaker）, and the position of ridge line is on the south （north） side, and the ridge point is on the east （west） side; the west wind circulation over Eurasia is weaker （stronger）, so the meridian （zonal） circulation plays a leading role.

关 键 词：汛期降水 气候变化特征 典型旱涝年 环流特征量 

分 类 号：P434[天文地球—大气科学及气象学] P457.6