Simulating temporal and spatial variation of evapotranspiration over the Lushi basin
Simulating temporal and spatial variation of evapotranspiration over the Lushi basin
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DOI：
10.1016/j.jhydrol.2003.08.013
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发表时间：
2004-01
影响因子：
6.4
通讯作者：
X. Mo;Suxia Liu;Zhonghui Lin;Weimin Zhao
中科院分区：
文献类型：
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作者：
X. Mo;Suxia Liu;Zhonghui Lin;Weimin Zhao
建立了一个基于过程的分布模型，模拟了鲁氏流域蒸散发的时空变化。模型组件包括地表阻力、能量传递、土壤水分运动、截留和地表径流的参数化。在我们的模型中，通过引入一个与参考高度的水汽亏缺相关的工作变量来分配蒸散发的方案是与众不同的。将流域划分为6227个网格，分辨率为30×30角秒。采用数字高程模型对气象变量进行海拔校正，采用距离平方反比法对流域降水进行空间插值。利用1996年遥感归一化植被指数（NDVI）和土地利用/覆被数据（分辨率为30×30弧秒）反演植被叶面积指数（LAI）的分布。1996年ndvi LAI模拟的蒸散量与物候LAI模拟的蒸散量接近。1992年、1995年和1996年逐月综合NDVI反演的LAI模拟的1984 - 1997年蒸散发年量差异小于30 mm yr - 1（或5%），其中1995年为干旱，1992年为湿润。1984 ~ 1997年的年蒸散发加土壤储存量变化与降水减去出口流量的变化吻合较好。1996年全年蒸散发及其组分的空间格局与流域降水和LAI的空间格局具有明显的对应关系。月蒸散量（ETm）在7 ~ 8月最高，为104 mm /月。灌溉农田的etm值全年均高于其他植被类型，草地和干旱农田的etm值相似，夏季均比森林植被高约10 mm月−1。1996年鲁石流域年蒸散量预测值为628 mm，蒸腾量预测值为327 mm，土壤蒸发量预测值为256 mm，林冠截留量预测值为45 mm。
A process-based distributed model is established to simulate the temporal and spatial variation of evapotranspiration over the Lushi basin in China. The model components include the parameterization of land surface resistances, energy transfer, soil water movement, interception and surface runoff. What is distinguished in our model is the scheme for evapotranspiration partition by introducing a working variable related to the water vapor deficit at the reference height. The basin was divided into 6227 grids with resolution of 30×30 arc seconds. A digital elevation model was used to correct meteorological variables for altitude, and the inverse distance square method was adopted for spatial interpolation of precipitation over the basin. The remotely sensed normalized difference vegetation index (NDVI) in 1996 and the land use/cover data, both with the resolution of 30×30 arc seconds, were used to retrieve the distribution of vegetation leaf area index (LAI). The evapotranspiration simulated by using 1996 NDVI-derived LAI is close to that by using phenologically derived LAI. The differences of annual amounts of evapotranspiration from 1984 to 1997 simulated by using LAI derived by 1992, 1995 and 1996 monthly composite NDVI are less than 30 mm yr−1(or 5%), in which 1995 represents drought and 1992 wet. The simulated annual evapotranspiration (ETa) plus soil storage change from 1984 to 1997 is in good agreement with precipitation minus discharge at the outlet. The spatial pattern of annual evapotranspiration and its components in 1996 clearly corresponded to the precipitation and LAI patterns over the basin. The highest monthly evapotranspiration (ETm) occurred in the period of July to August with 104 mm month−1. The value of ETmfor irrigated farmland is higher than that for other vegetation types all the year and the values of ETmfor grass and arid farmland are similar and about 10 mm month−1higher than those for forest covers in summer. The predicted annual evapotranspiration in 1996 over the Lushi basin is 628 mm with the transpiration 327 mm, soil evaporation 256 mm and canopy interception 45 mm, respectively.