蒸散发是水循环中的一个重要过程,研究蒸散发对农业灌溉、水资源合理利用和地区生态环境的可持续发展均有重要意义。本文基于Landsat TM数据和SEBAL模型,详细介绍了日蒸散发遥感估算的方法,分析了黄河三角洲蒸散发的数值特征和空间格局特征,并在此基础上研究了土地利用类型与蒸散发的关系。结果表明,2009年6月4日黄河三角洲日蒸散发量在0-9.11mm,平均值为5.31mm。蒸散量的空间分异特征较为显著,受下垫面条件的影响突出,高值区主要分布在东部以林地为主的国家级自然保护区和河口区大范围的盐田和养殖池、中部东营市区周边的平原水库区以及南部广饶县的优质农田区域。水体、林草地、建设用地和未利用地的日蒸散发空间分布频率图均呈单峰分布,耕地受作物类型空间分布差异等因素的影响而呈现为较明显的双峰分布。土地利用类型决定了日蒸散发的水平,不同下垫面蒸散发量的日均值从大到小依次为：水体、滩涂、苇地、林草地、耕地、建设用地和未利用地。

Evapotranspiration (ET) is an important part of the water cycle; therefore, the studies on ET are of great importance to the improvement of irrigation efficiency, regional wise water management, and the sustainability of ecosystem. The calculation method of daily ET using Landsat TM and Surface Energy Balance Algorithm for Land (SEBAL) model is described in detail. Furthermore, the quantitative characteristics, spatial patterns of ET are analyzed. And then, the spatial relationships between ET and land utilization types are studied. The result shows that ET ranges from 0.05 mm to 9.11 mm with the mean value of 5.31 mm. Spatial differences of daily ET in the Yellow River Delta (YRD) are significant for different land utilization types. High ET are mainly distributed in the National Nature Reserve located in the eastern part of Dongying City, saltern and sea water culture zones in the Hekou District, the surrounding reservoirs of the central urban area of Dongying City, and high-quality farmland in Guangrao Country. The daily ET takes on a single-peak curve in water body, grassland and forest, construction area, and unused land, but a double-peak curve in farmland. Land utilization types decide the level of ET. The mean values of daily ET in the descending order are water body, beach, reed land, grassland and forest, farmland, construction area, and unused land.