三峡地区旱涝多时间尺度变化特征及旱涝年大气环流异常  

Variation Characteristics of Multiple Time Scales of Drought/Flood and Atmospheric Circulation Anomaly in Drought/Flood Years in the Three Gorges Area

作　　者：李强[1,2] 李永华[2,3] 周锁铨[2] 王中 

机构地区：[1]重庆市气象台,重庆401147 [2]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044 [3]重庆市气象科学研究所,重庆401147

出　　处：《气候与环境研究》2011年第2期243-254,共12页Climatic and Environmental Research

基　　金：重庆市自然科学基金计划重点项目CSTC2008BA0022;中国气象局成都高原气象研究所开放基金项目LPM200814;中国气象局武汉暴雨研究所暴雨基金项目IHR2007G03

摘　　要：根据Z指数指标体系,构建了三峡地区旱涝指数时间序列,且利用Morlet小波分析方法研究了指数序列的多时间尺度演变特征和典型夏季旱涝年大气环流特征,结果表明:三峡地区干旱、雨涝有明显不同的年际、年代际特征,年、四季的干旱指数与雨涝指数基本呈反位相特征。三峡地区旱涝指数Morlet小波分析表明,在不同时间和频率域中,有显著的周期振荡,具有较强的局部特征;年旱涝指数主要有准5年、准9年、准15年的周期振荡;旱涝特征周期振荡也具有明显的季节性差异。三峡地区雨涝年的环流背景为乌拉尔山地区、西伯利亚、巴尔喀什湖地区上空位势高度偏高,我国河套地区、华北平原至日本海上空的位势高度偏低;干旱年的环流形式与之相反。The time series of drought and flood indices in the Three Gorges area are constructed according to Z-index system and the multiple time scales variation characteristics of the index series are analyzed by using Morlet wavelet transform method.The atmospheric circulation characteristics in the typical summer drought/flood years are investigated.It is found that the drought/flood variation is characterized by obvious interannual and interdecadal changes in the Three Gorges area.The drought index and the flood index time series have almost anti-phase variations on the annual and seasonal time scales.The Morlet wavelet analyses show that the drought and flood indices in the Three Gorges Reservoir area have remarkable periodic oscillation and obvious local features in different time and frequency distributions.There are quasi-5-year,quasi-9-year,and quasi-15-year interdecadal periodical oscillations.The periodical oscillations of the drought and flood features have significant seasonal differences.In flood years,the atmospheric circulation background in the Three Gorges Reservoir area shows that the anomaly of 500-hPa geopotential height field is positive in the Ural Mountains,Siberia,and Lake Balkash,and negative in the Loop area and North China Plain as far as the Sea of Japan.The atmospheric circulation anomaly is opposite in drought years.

关 键 词：三峡地区 旱涝 Z指数 MORLET小波 

分 类 号：P461[天文地球—大气科学及气象学]