川渝盆地夏季旱涝变化特征及成因分析  

Features of Summer Precipitation Change of the Chuanyu Basin and Its Relationship with Large-Scale Circulation

作　　者：陈权亮[1,2] 倪长健[1] 万文龙[1,3] 

机构地区：[1]成都信息工程学院高原大气与环境四川省重点实验室,四川成都610225 [2]中国气象局成都高原气象研究所,四川成都610071 [3]山东省东营市气象局,山东东营257091

出　　处：《高原气象》2010年第3期587-594,共8页Plateau Meteorology

基　　金：成都信息工程学院科研启动项目(KYTZ201005);中国气象局成都高原气象开放实验室基金课题(LPM2008005)共同资助

摘　　要：利用川渝盆地18个观测站1955—2008年的月平均降水资料,分析了川渝盆地东、西部夏季降水的年代际变化特征;通过NCEP/NCAR再分析资料、NOAA OLR资料,分析了川渝盆地东、西部多雨年和少雨年的环流形势,结果表明:(1)川渝盆地东、西部夏季区域平均降水量呈负相关关系,且川渝盆地东、西部夏季降水的长期变化周期也有一定的差异。(2)在川渝盆地西部多雨年,500 hPa高度上北半球欧亚地区两脊一槽型环流发展,孟加拉湾的低气压有利于水汽从西南方向输送到我国,同时南亚高压西部增强,使得川渝盆地西部和我国河套地区降水偏多。而在川渝盆地东部多雨年,东亚高纬度地区经向环流有利于我国东部冷空气南下,配合副热带高压西伸,南亚高压东部减弱,我国中部地区和川渝盆地东部降水偏多。(3)前期春季OLR场特征对后期夏季川渝盆地夏季降水的预测有一定的指示意义。在川渝盆地西部多雨年,印度洋到孟加拉湾整个地区前期春季OLR减小,印度洋和孟加拉湾地区的对流活动增强,有利于水汽输送到川渝盆地西部地区。而川渝盆地东部多雨年,从南海向我国的水汽输送增强,盆地东部地区降水偏多。Monthly mean precipitation data at 18 stations of Chuanyu basin from 1955 to 2006 is used to analyze the variation of summer precipitation.Then the NCEP/NCAR reanalysis data and OLR data from NOAA are used to analyze the precipitation change with the large-scale circulation.The results show that：（1） The summer precipitation change phase of the west and east parts of Chuanyu basin is opposite,and the most frequent rain pattern is less precipitation in the west of Chuanyu basin and more precipitation in the east.（2） In more summer precipitation years of the west,it is associated with the circulation that two ridges and one trough in mid-high latitudes.And the low pressure in the Bay of Bengal reduces so that the south-west vapor transport enhances.South Asian High（SAH） enhanced in the west.These result in the more precipitation in the west of Chuanyu basin.At the same time,in more summer precipitation in the east of Chuanyu basin,the meridional circulation in East Asia and the west spread of the subtropical high as well as the reduce of the SAH result in the more precipitation in the east of Chuanyu basin.（3） The previous spring OLR has indicative signal of the change of summer precipitation in the west and east of Chuanyu basin.In more rain years of the west of Chuanyu basin,the previous spring OLR decreases from Indian Ocean to the Bay of Bengal.While in more rain years of the east of Chuanyu basin,the vapor transportation from the South China Ocean enhances.

关 键 词：川渝盆地 夏季降水 大尺度环流 OLR 

分 类 号：P426.616[天文地球—大气科学及气象学]