浙江省金衢盆地降水和蒸发变化及其周年分布

过对金华市1960－1997年不同年份的降雨量和蒸发量进行了统计分析，结果表明，60年代以来降雨量平均每年增加3．35mm,蒸发量平均每年下降10．70mm，干湿指数由60年代的0．79上升至90年代的1．03，变异度下降，说明盆地的水汽条件在逐步改善。各季节历年降雨变化声势分析表明，夏秋季降雨量的增加较快，但周年分布仍极不均匀，3月中旬－7月上旬的春夏季降雨量达812．6mm，占全年的56．8％，7月中旬－8月中旬的夏旱季仅110．6mm，而蒸发量是它的3倍多，且不同年度的降雨总量、夏秋季不同年度的降雨量变化较大，降雨集中强度和蒸发集中强度的分析也说明金衢盆地春夏季降水集中，夏秋季高温少雨的季节性气候特征非常明显，因此，生产上应十分重视特殊降水年份的洪涝灾害和夏秋季大旱与特大旱的防御工作。

Analysis on the change of rainfall and evaporation in the Jinqu basin in Zhejiang province

Statistical analysis on the rainfall and evaporation data of Jinghua Meteorological Station from 1960 to 1997 was carried out and the linear model of rainfall and evaporation was developed. The results showed that average rain rate increased 3.35 mm/y and average evaporation rate decreased 10.70 mm/y since 1960. The ratio of rainfall over evaporation increased from 0.79 in 1960's to 1.03 in 1990's, while the cv% of the ratio decreased,is becoming suggesting that the water condition is becoming better. Seasonal distribution of rainfall indicated that rainfall rate in draught season from July to November higher increased rate greater than that in other seasons. However, the rainfall distribution was still uneven around year. It was 812.6 mm from March 1 to July 10, which was 56.8% of annual rainfall, and 110.6 mm from July 11 to August 20, which was less than 1/3 of its evaporation. Therefore, more attention should be paid on serious drought and flood in special rainfall year.