Uncertainty analysis of actual evapotranspiration reconstructed with GRACE gravity satellite data in the Jinsha River BasinEI北大核心CSCD

通过GLDAS数据对GRACE重力卫星水储量数据进行降尺度处理,采用水量平衡方程重构了金沙江流域2007—2016年25个子流域月实际蒸散发数据,采用拉丁超立方抽样法确定各水量平衡参数的不确定性,并对各参数和实际蒸散发进行不确定性分析。结果表明:抽样样本数为415时,抽样结果较好,各参数中降水量的不确定性变化范围最大,水储量变化次之,径流深最小;金沙江流域年均实际蒸散发不确定性变化范围为46.02~146.19 mm,空间分布总体上表现为自西向东、自北向南逐渐增大的趋势,信噪比分布与不确定性分布有一定的相似性;在年、季节尺度下,流域内不同土地利用类型的实际蒸散发不确定性由大到小排序均为林地、灌丛、农田、草地、其他占地类型;实际蒸散发不确定性在季节上呈现出差异性,夏季不确定性变化范围最大,冬季最小。

Uncertainty analysis of actual evapotranspiration reconstructed with GRACE gravity satellite data in the Jinsha River Basin

GLDAS data was used to downscale the water storage data of GRACE gravity satellites, and the actual monthly evapotranspiration (AET) data of 25 sub-basins in the Jinsha River Basin from 2007 to 2016 were reconstructed with the water balance equation. The uncertainty of each water balance parameter was quantified by the Latin hypercube sampling method, and the uncertainty analysis of every parameter and AET was carried out. The results showed that the sampling results were satisfactory when the sample size was set to 415.Precipitation had the largest uncertainty range, followed by the change of water storage, and runoff depth had the smallest uncertainty range. The spatial distribution of AET uncertainty in the Jinsha River Basin showed an increasing trend from west to east and from north to south, with the data ranging from 46.02 mm to 146.19 mm, and it was similar to the spatial distribution of AET signal-to-noise ratio. At the annual and seasonal scales, the AET uncertainty of different land-use types in the river basin was ranked from high to low as follows:woodland, shrub, farmland, grassland, and other land types, and the AET uncertainty varied seasonally, with the largest variation range in summer and the smallest in winter.