基于遥感的泾河流域日蒸散量估算

Estimation of Daily Evapotranspiration Based on Remote Sensing Data in Jinghe Basin

蒸散发是陆地水分和能量循环过程中的重要环节。利用遥感数据与传统蒸散发模型相结合的方法,对泾河流域2006年3—10月日实际蒸散量进行动态模拟,并利用LAS站实测数据对模拟结果进行了验证。结果表明:1)基于遥感的P-T方法估算地表实际蒸散发可获得较好的效果。2)泾河流域蒸散发空间上,总体趋势为"南高北低;东西两侧山区高,中部平原低";林地蒸散量最高,其次为农田,最低的是草地。3)时间上,泾河流域蒸散发呈单峰型分布,7月、8月份的蒸散发量最高。4)月均气温、月降雨量和月均植被指数与月均蒸散发量的相关系数分别在0.8,0.5,0.7左右,表明温度、降水和植被是影响泾河流域蒸散发的关键因素。

Evapotranspiration （ET） is a key process in the global water and energy cycle. It is convenient to estimate the spatiotemporal variation of ET using remote sensing techniques. The regional ET model driven by remote sensing was built by coupling the conventional ET model with remote sensing data. Daily ET was estimated from March to October of 2006 in the Jinghe basin. The estimation was validated with LAS data. The results showed that： 1） the estimation using the P-T method based, on remote sensing met the observa- tions well; 2） spatial distribution patterns indicated that ET was higher in lower latitudes and mountainous areas than in higher latitudes and plains, and ET of forest ranked the highest among other land cover types; 3） ET presented a unimodal distribution and peaked in July and August; 4） strong correlations were found between monthly ET and the monthly average temperature, monthly precipitation, and vegetation index, the correlation coefficients were 0. 8, 0.5 and 0.7, respectively. Temperature, precipitation and vegetation index were the major factors affecting the daily ET in Jinghe basin.