我国北方1986年和1997年干旱事件环流异常对比分析  

Comparative Analysis on Atmospheric Circulation Anomalies of Heavy Drought Event in Northern China in 1986 and 1997

作　　者：段海霞[1] 李耀辉[1] 刘芸芸[2] 

机构地区：[1]中国气象局兰州干旱气象研究所,甘肃省(中国气象局)干旱气候变化与减灾重点(开放)实验室,甘肃兰州730020 [2]中国气象局国家气候中心,北京100081

出　　处：《干旱区研究》2015年第5期966-976,共11页Arid Zone Research

基　　金：国家自然基金项目(41175081);公益性行业(气象)科研专项经费(GYHY201006023)资助

摘　　要：利用中国逐日站点降水资料、逐日季风监测指数及逐日副热带高压指数、74项环流指数及NCEP/NCAR再分析资料,分析我国北方地区1986年和1997年夏季发生的干旱过程中大气环流及海温异常特征。结果表明:1与1986年相比,1997年旱情持续时间更长,受旱程度相对更为严重,波及范围更广,且旱区气温偏高;2 1986年和1997年夏季2次北方干旱过程西太副高演变差别明显。1986年西太副高位置整体较常年平均偏东略偏南,面积偏小,强度偏弱,与之相比,1997年副高位置偏西偏南,面积偏大,强度偏强;3 2次过程中上升运动条件和水汽条件相似,旱区主要以下沉运动及下沉运动距平为主,而且来自南海和孟加拉湾的水汽均不足,导致干旱少雨;4太平洋海温分布的不同,影响了2次过程西太副高南北和东西振荡的差异,进而影响了2次干旱过程干旱区域分布的不同。In order to study the features and causes of the drought disasters,the two drought events and their atmospheric circulation anomaly occurred in the northern China in summer of 1986 and 1997 is examined using daily stations precipitation data,daily monsoon monitoring index,daily subtropical high index,74 atmospheric circulation indices and NCEP / NCAR reanalysis data. The results show that,in comparison with 1986,the drought in 1997 had a longer duration,stronger disaster degree and larger range. The two Western Pacific Subtropical High（ WPSH） evolutions showed a significant difference. This results display that the WPSH position is stronger and larger,in comparison with 1986,in addition to a shift to the west and south. This results in less water vapor transport from the tropical Indian Ocean and the South China Sea,and the sinking motion anomaly. Furthermore,the analysis of Pacific sea surface temperature showed that distribution of different equatorial and northwest Pacific SSTs affected different oscillation of the North-South and East-West of WPSH,thereby affecting the different arid region distribution in the two drought process.

关 键 词：干旱事件 环流指数 大气环流 海温距平 水汽输送 

分 类 号：P434[天文地球—大气科学及气象学]