小型蒸发器的水面蒸发量折算系数

Conversion Coefficient between Small Evaporation Pan and Theoretically Calculated Water Surface Evaporation in China

利用1957—2001年全国472个测站小型蒸发器的实测资料及水面蒸发量的理论计算值,对比分析了两者折算系数的分布规律及45 a来的年际变化,同时利用各气象要素建立了回归模型。结果表明,年平均折算系数的全国平均值在0.622左右波动,变幅较小。年平均折算系数较大的地区集中在新疆天山以北、陕西南部和105°E以东的长江流域;内蒙瀚海盆地和横断山脉北部较小。45 a来,286站的年平均折算系数发生了变化,其中96%站点的变化率在±0.04/(10 a)之间。

Based on the observational data of small evaporation pan and theoretically calculated water surface evaporation of 472 meteorological stations in China from 1957 to 2001,the distribution character of conversion coefficient and its tendency during the past 45 years are studied.At the same time the regression model of conversion coefficient is given using different meteorological factors.The results indicate that national average annual conversion coefficient oscillated around 0.622 with a small amplitude.The maximal annual conversion coefficients occurred in the northern of Tianshan,the southern of Shanxi and the Yangtze River valley east of 105°E;while the minimum in Hanhai basin and the northern of the Hengduan Mountains.In the past 45 years,the conversion coefficients of 286 stations were decreasing or increasing,with a change rate within ±0.04/（10 yr） at 275 stations of the 286 stations.