黑河流域上中下游潜在蒸散发变化及其影响因素的差异

通过黑河流域及其周边气象站点的气象数据,对比分析了1958~2005年黑河流域上中下游潜在蒸散发变化的不同趋势及气象因子的不同影响.黑河流域上游山区潜在蒸散发具有弱增大的趋势,主要表现为辐射项的增大;中下游绿洲潜在蒸散发具有显著下降的趋势,主要表现在空气动力学项的减小.通过相关性分析发现,太阳辐射和平均气温是辐射项的主要因素,而风速和相对湿度是空气动力学项的主要因素.气温升高对上游山区潜在蒸散发的增大具有显著影响,而风速下降对中下游绿洲潜在蒸散发的影响非常显著.

Differences of changes in potential evapotranspiration and its factors over the upper,middle and lower reaches of Heihe River Basin

The differences of changes in potential evapotranspiration from 1958 to 2005 in the upper,middle and lower reaches of the Heihe River Basin and the relationships of these changes to meteorological factors were assessed using data from meteorological stations in and around the study area.Weak increasing trends in potential evapotranspiration were found in the upper mountainous reach,which were primarily due to the increases in the radiation terms.The decreasing trends in potential evapotranspiration were found in the middle and lower oasis reaches,which were primarily due to the decreases in the aerodynamic terms.According to the correlation coefficients,the changes in air temperature and solar radiation were the main reasons for the trends in the radiation term,and the changes in wind speed and relative humidity were the main reasons for the trends in the aerodynamic term.The increasing in air temperature is main factor of the weak increase in potential evapotranspiration in the upper mountainous reach,and the decreasing in wind speed is the main factor of the decrease in potential evapotranspiration in the middle and lower oasis reaches.