福建初夏(7月)旱涝特征的对比分析

Comparing analysis of feature of drought and waterlogging on primary summer(July) in Fujian

以全省 2 5个代表站 1 96 0～ 2 0 0 0年 7月的降水资料和北半球 50 0hPa高度资料、北太平洋海温的月平均资料为素材 ,首先标定典型旱涝年例 ,其次揭示降水的演变规律 ,最后对比分析典型旱涝年例的 50 0hPa环流背景和海温特征 ,得出以下几点初步结论 :1 )福建初夏发生干旱年例和洪涝年例各约“十年二遇” ;2 ) 2a、5～ 7a、1 9a和 9a的周期振动较为明显 ;3)北半球极涡偏弱 (强 ) ,乌拉尔山附近的阻塞形势较为明显(不够明显 ) ,冷空气路径比较偏东 (西 ) ,西太平洋副高偏强 (弱 )偏南 (北 ) ,东亚中纬度高度场偏低 (高 ) ,太平洋中部槽加深 (槽较浅 ) ,东亚地区高、中、低纬的距平为“ +- +”(“ - +-”)分布特征 ,在这环流形势的配置下 ,为福建初夏发生干旱 (洪涝 )提供有利的环流背景 ;4 )黑潮区海温偏高 (偏低 ) ,而太平洋中东部赤道附近海域海温偏低 (偏高 )时 ,福建初夏易于发生干旱 (洪涝 ) .

The precipitation data in July at 25 representative meteorological stastions in Fujian Province,500hPa height data in northern hemisphere and monthly mean data of sea temperature in north Pacific from 1960 to 2000 were selected. First the model of drought and waterlogging years were defined. Next the variable regularity of precipitation was revealed. Finally the model feature of 500hPa circulation and sea temperature in drought years and waterlogging years was comparatively analyzed,four primary results were found:1) The drought years and waterlogging years were about 'two times in ten years' in primary summer in Fujian Province; 2) 2a, 5～7a, 19a and 9a periodic vibrations were comparatively evident; 3) The polar vortex in northern hemisphere was weaker(stronger) than normal, the blocking position around the Ural Mountain was comparatively evident(misty), the path of cold air was by east(west),the subtropical high over the West Pacific was stronger (weaker) and by south (north), height of mid latitude in East Asia was lower(higher), the trough of centre in Pacific was deeper(shallower), the distribution characteristics anomaly of high ,middle, low latitude in East Asia was '+-+'('-+-') , those results were helpful to provide a favourable circulation background for causing drought(waterlogging) in primary summer in Fujian Province under this circulation collocation;4)When the sea temperature was higher(lower) than normal in Kuroshio region,and lower(higher) than normal on the eastern section of mid Pacific round equatorial region,the drought(waterlogging) were easily occured in primary summer in Fujian Province.