浙江省金衢盆地降水和蒸发变化及其周年分布

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

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上升到 90年代的 1.0 3,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趋势分析表明 ,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 。

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.