基于SEBAL模型的渭-库绿洲蒸散量特征及影响因子研究

Characteristics and Impact Factors of Evapotranspiration in Ugan and Kuqa Rivers Delta Oasis Based on SEBAL Model

对渭-库绿洲蒸散发量的估算在绿洲水资源管理和分配以及生态环境的保护方面扮演着重要作用,同时对于深刻了解流域水循环和水文过程也具有重要意义。本文以渭干河-库车河绿洲为研究靶区,将Landsat TM/OLI遥感数据与地面气象站点实测数据相结合,利用SEBAL模型估算了渭-库绿洲1997年和2016年的日蒸散量,并对日蒸散量的空间分布特征及日蒸散量与相关地表参数的相关性进行了分析。结果表明:渭-库绿洲日蒸散量的空间分布表现为西高东低,北高南低的分布特征,其高值出现在水体和植被覆盖较多的绿洲内部区域,低值则分布在研究区东、东南和西部的低植被覆盖区域;在日蒸散量与植被指数(NDVI、SAVI、LAI)、水体指数(MNDWI、NDWI、TVI、VSWI、TVDI)和地表温度(LST)等地表参数的相关性方面,研究时段内全部地表参数与日ET具有较高的相关关系,Pearson相关系数都通过0.01水平的显著性检验,其中NDWI与日蒸散量表现出了最好的相关性,表明在渭-库绿洲水分对日蒸散量分布与变化的影响是最大的。

The arid zone refers to the arid climate area, which accounts for about 30% of the land area. The common characteristics are： the precipitation is low and the change rate is large, the ranges of both the daily and annual temperature are large, and the evaporation is far greater than the precipitation. Thus, the estimation of evapotranspiration in the Ugan and Kuqa Rivers Delta Oasis plays an important role in the management and allocation of water resources. At the same time, it has a great significance to understand the water cycle and hydrological process of the study area. In this paper takes the Ugan and Kuqa Rivers Delta Oasis as the study site, the daily evapotranspiration of Ugan and Kuqa Rivers Delta Oasis in 1997（August 30） and 2016（August 2） was estimated, and the spatial distribution characteristics of daily evapotranspiration, and the correlation between daily evapotranspiration and relative surface parameters were analyzed by combining Landsat TM/OLI remote sensing images with meteorological data, and using SEBAL model. The results showed that the spatial distribution of daily evapotranspiration in the Ugan and Kuqa Rivers Delta Oasis was characterized by distribution patterns of high to low from west to east, and from north to south. The high value appeares in the oasis area covered with abundant water and vegetation, and the low value is distributed in the east, southeast and west part of the study area with the low vegetation coverage. In terms of the correlation between the daily evapotranspiration and surface parameters, such as vegetation indices （NDVI, SAVI, LAI）, water indices （MNDWI, NDWI, TVI, VSWI, TVDI） and land surface temperature （LST）, the daily evapotranspiration showed the good correlation with every index. The Pearson correlation coefficients past the significance test at 0.01 level, especially with a best correlation with NDWI. the results indicate that water bodies are the most important factor for distribution and changes of the daily evapotranspiration in the Ugan and Kuqa Rivers Delta Oasis.