西辽河平原蒸发皿蒸发量的气候变化特征分析

Analysis of the Change Trend of the Evaporation on the Xiliao River Plain

利用西辽河平原3个气象站1951--2007年逐月20cm口径蒸发皿蒸发量资料，分析了西辽河平原蒸发量的变化趋势．结果表明，1951--2007年西辽河平原蒸发皿蒸发量在年内呈单峰型分布，蒸发量最小值出现在1月，最大值出现在5月份；近57年来蒸发皿蒸发量总体呈明显下降趋势，蒸发量气候倾向率为-42．9mm／10a，其绝对值高于全国平均水平．不同季节蒸发皿蒸发量变化趋势有所不同，蒸发量下降主要在春季和夏季，秋季不明显，而冬季蒸发量呈上升趋势．

Analyzed the change trend of the evaporation on the Xiliao River plain, through using the evaporation material of evaporating dish which is 20cm caliber from 1951 to 2007 month by month, and there are 3 weather stations on the Xiliao River plain. The result indicated that, the evaporation of Xiliao River plain evaporating dish assumes the unimodal distribution from 1951 to 2007, the minimum of the evaporation appears in January and the maximum appears in May. The evaporation of evaporating dish assumes the obvious drop tendency overall in the resent 57 years. The climate tendency rate of the evaporating is - 42.9mm/10a, and its absolute value is higher than the national average level. The change trend of the evaporation of evaporating dish is different in the different season. The evaporation mainly drops in the spring and the summer, the autumn is not obvious,but the winter evaporation assumes the trend of escalation.