Evapotranspiration (ET) was estimated from 1981–2005 over Wushen Countylocated in the Mu Us Sandland, China, by applying the Advection-Ariditymodel, which is based on the complementary relationship hypothesis. We usedNational Oceanic and Atmospheric Administration (NOAA) Advanced Very HighResolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer(MODIS), and meteorological data. Our results show that the estimated dailyET was about 4.5% higher than measurements using an Eddy Covariance (EC)system after forcing energy balance closure over an alfalfa field from 22July 2004 to 23 August 2004. At a regional scale, the estimated monthly ETwas about 8.7% lower than measurements using the EC system after forcingenergy balance closure over an alfalfa field in August 2004. These resultswere about 3.0% higher than ET measurements by microlysimeter over sanddunes during June 1988. From 1981 to 2005, the average annual ET andprecipitation levels were 287 mm and 336 mm, respectively, in Wushen County.The average annual ET varied from 230 mm in western parts of Wushen Countyto 350 mm in eastern parts of the county. Both inter-annual and seasonalvariations in ET were substantial in Wushen County. The annual ET was200–400 mm from 1981–2005, and the seasonal pattern of ET showed a singlepeak distribution. The cumulative ET during the June–September 2004 periodwas 250 mm, which was 87% of the total annual ET. The annual ET,precipitation, and the maximum Normalized Difference Vegetation Index(NDVImax) showed positive correlations temporally and spatially.
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机译：应用对流-干旱模型（基于互补关系假设），对1981年至2005年位于中国毛乌素沙地的乌审县的蒸散量进行了估算。我们使用了美国国家海洋和大气管理局（NOAA）的超高分辨率高分辨率辐射计（AVHRR），中等分辨率成像光谱仪（MODIS）和气象数据。我们的结果表明，从2004年7月22日至2004年8月23日，在苜蓿田上强制关闭能量平衡之后，估计的每日ET大约比使用涡流协方差（EC）系统的测量高4.5％。在区域范围内，估计的每月ET约为8.7比2004年8月在苜蓿田强制关闭能量平衡后，使用EC系统的测量结果降低了％。这些结果比1988年6月在沙丘上用微量测微仪测量的ET高出约3.0％。从1981年到2005年，年平均ET和降水量为287乌审县的毫米分别为336毫米和336毫米。乌申县西部的年平均ET从230毫米变化到东部的350毫米。乌审县ET的年际和季节变化都很大。从1981年至2005年，年ET值在200-400 mm之间，并且ET的季节模式显示出单峰分布。 2004年6月至9月期间的累积ET为250毫米，占年度ET总量的87％。年度ET，降水量和最大归一化植被指数（NDVI max ）在时间和空间上呈正相关。
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