宁波市年降水量时空变化特征

应用主分量分析、气候突变检验、“墨西哥帽”小波分析及谱分析等多种方法对宁波市1953~2003年的年降水量进行了时空特征分析。结果表明:宁波市所辖7个气象站年降水量呈现出从西南往北—东北方向递减的趋势,与全市地形走向基本一致,年降水量最大、最小值相差400 mm左右;全市各地年降水量的年际变化趋势是一致的;宁波市区年降水量在20世纪60年代末到70年代初接近突变临界值,近年也有发生转折的趋势;进入21世纪以来,宁波市年降水量处于偏少的气候背景中,2003年变化最为剧烈;宁波市区年降水量有准4年的振荡周期。

Spatial and Temporal Characteristics of Annual Precipitation in Ningbo

Based on the 51-year annual precipitation data of Ningbo from 1953 to 2003,a detailed analysis is performed by means of several diagnosis methods,including EOF,climatic abrupt change testing,Mexico hat wavelet and spectrum analysis.The results show that annual rainfall amount across the city tends to descend from the southwest to north-northeast,which accords with the topographic features of the city;the difference between maximum and minimum precipitation is about 400 mm.EOF1 of spatial characteristic vectors indicates that the annual precipitation of all the seven weather stations has a coincident tendency.Ningbo experienced an abrupt climate change in annual precipitation during the late 1960's and the early 1970's,and another significant change took place in recent years.The annual precipitation has been less than normal since the beginning of the 21st century with the minimum in 2003.There is a quasi-four year periodicity in annual precipitation.