福建伏旱期旱涝环流特征及其预测探讨

DISCUSSION ON FORECAST OF DROUGHT AND FLOOD CIRCUMFLUENCE CHARACTER IN HOT SEASONS OF FUJIAN

本文取 196 0～ 2 0 0 0年全省 2 5个代表站 7月降水资料和北半球5 0 0hPa高度场资料、以及 5 0 0hPa面上的极涡、中纬度环流、青藏高原高度场 (即高原地区等压面高度场 )、副热带高压等 74个环流指数为素材 ;首先标定伏旱期降水的异常指数和严重旱涝年例 ,其次分析严重旱涝年例的 5 0 0hPa环流背景 ,最后揭示预测概念模型 ,得出秋冬季北半球副热带高压 ,欧亚经向环流和青藏高原高度场的变化是预测福建伏旱期降水的强信号因子。

The precipitation data of 25 representative meteorological stations in Fujian,500hpa height in northern hemisphere,polar vortex,meso-latitude circumfluence,Tibetan plateau height ,subtropical high and so on circumfluence index during July from 1960 to 2000 were selected.Firstly,the anomalous index and years of precipitation in hot season were defined.Secondly,the 500 hPa circumfluence background of severity drought and flood years were analysed.Finally,the forecast concept model was exposed. The primary results are found:(1) The circumfluence characters in drought years are found: Polar vortex of northern hemisphere is feeble,Ural blocking high is evident,the path of cold air is partial to be east,subtropical high of West-Pacific is strong,meso-latitude height on East-Asia is low,the trough on meso-Pacific increases,the anomaly of 500 hPa at high,median,low latitude on East-Asia region is positive ,negative and positive,respectively.(2)The circumfluence characters in flood years are found:Polar vortex of northern hemisphere is strong,Ural blocking high is not evident,the path of cold air is partial to be west,subtropical high of West-Pacific is feeble,meso-latitude height on East-Asia is high,the trough on meso-Pacific decreases,the anomaly of 500 hPa at high,median,low latitude on East-Asia region is negative,positive and negative,respectively.(3)The subtropical high in northern hemisphere in autumn-winter,the longitude circumfluence on Europe-Asia region and Tibetan plateau height change are strong signal gene for forecast of precipitation in hot season of Fujian.