河北省旱涝的变化特征及其相关的海气异常型分析

利用河北省及邻近区域73个气象站1961—2009年逐年降水资料,同期NCEP/NCAR再分析资料,NOAA太平洋海温等资料,分析了河北省干旱的时空变化特征,并应用奇异值分解、合成分析等方法,研究了河北省典型旱涝年份与同期太平洋海温场和环流场的异常特征.结果表明：河北省旱涝异常的空间型分布主要有2种,这些空间型的时间变化除了具有明显的年际变化外,还存在显著的年代际变化.SVD（奇异值分解）分析揭示的河北省旱涝和海气异常的关系表明,当赤道东太平洋年平均海温异常偏低,北太平洋海盆中部年平均海温异常偏高的年份,河北省大部分地区容易偏涝,反之,易干旱.典型干旱年,500hPa平均高度场上贝加尔湖西南部以及极地500 hPa年平均高度场为正异常,阿留申地区南部为负异常;亚洲中高纬地区环流从西到东呈现-＋-的环流异常纬向分布.而典型雨涝年500 hPa平均高度场上贝加尔湖西南部以及极地500hPa年平均高度场为负异常,阿留申地区南部为正异常;亚洲中高纬地区环流从西到东呈现-＋的环流异常纬向分布.

Variability of drought/flood in Hebei province and associated atmospheric and oceanic pattern analysis

Based on 73 meteorological stations＇ annual precipitation data during 1961—2009 in Hebei province and its vicinity,NCEP / NCAR reanalysis data and NOAA Sea Surface Temperature（ SST） data of the Pacific Ocean dur- ing the same period,the spatial and temporal distributions of drought / flood are analyzed. The relations between drought / flood in Hebei and contemporaneous anomalies of the SST field in the Pacific Ocean and the field of circu- lation are investigated by using Singular Value Decomposition（ SVD） and composite analysis methods. The research shows that,there are mainly two patterns in the anomalous distributions of drought / flood in Hebei,with temporal variations in not only inter-annual but also inter-decadal time scale. The coupling relationship between drought / flood in Hebei and associated atmospheric and oceanic anomaly patterns with SVD analysis presents that,when the annual mean SST in equatorial eastern Pacific is abnormally low and the mean SST in the middle of the North Pacific Basin at the same time is abnormally high,it would always have flood in most regions of Hebei province,otherwise it would be a drought year. In drought years of Hebei province the positive anomalies over the southwestern of Lake Baikal and North Pole and the negative anomalies over the south of Aleutian region emerge at 500 hPa mean geopotential height fields. While the circulation anomalies display a latitudinal negative-positive-negative pattern at mid-and high-latitudes in Asia. Concurrent flood years pattern corresponded with the negative anomalies over the southwest- ern of Lake Baikal and North Pole and the positive anomalies over the south of Aleutian region emerge at 500 hPa mean geopotential height fields. At the same time,at mid-and high-latitudes there was latitudinal negative-positive a- nomalous circulation pattern in Asia.