基于MODIS数据的黄河三角洲区域蒸散发量时空分布特征

    Characteristics of the spatial and temporal distribution for regional evapotranspiration in the Yellow River Delta based on MODIS data

    • 摘要: 充分利用遥感手段的快速、准确、大尺度及可视化等优势,对地球表层水量转化过程中最难估算的分量-蒸散发量进行了估算。针对黄河三角洲地理位置特殊、石油生产基地的经济重要性、生态系统水资源压力日益增大等特点,采用理论基础较坚实、区域应用限制小、反演陆面蒸散发量较为合理准确的SEBS(Surface Energy Balance System)模型,基于MODIS数据估算了黄河三角洲区域陆面蒸散发量,分析了陆面蒸散发量的时空分布特征。研究结果表明:研究区年内陆面蒸散发量呈单峰型分布,季节性变化特征显著;陆面蒸散发量的空间分布在一定程度上受人类活动驱动的土地覆盖影响呈现出南高北低的趋势。水分盈亏分析表明:春季、秋季蒸散发相对较强烈,天然水分供给不足,灌溉需求较高,水资源丰枯状况对农业耕作、生态环境影响较大。

       

      Abstract: Estimation of land surface evapotranspiration (ET) is one of the most difficult tasks in the field of hydrology and water resources. In this study, ET in the Yellow River Delta is estimated using remote sensing techniques, which own the characteristics of high efficiency, precision, large-scale and visualization. The Yellow River Delta has a specific geographic feature and it is an important petroleum production base in China. However, the health of ecosystem in this region is just enduring severe water resources stress. Surface Energy Balance System (SEBS)model being an applicable model with good theoretic basis to estimate land surface ET with less meteorological data requirement, is used to estimate land surface ET in the Yellow River Delta on the basis of MODIS data. Results show that annual ET is single-peak distributed in month scale with a well seasonal variation. Spatially, ET in southern areas is generally greater than that in northern areas remarkably influenced by human-being activities. Results of water deficit analysis show that ET in spring and autumn is relatively higher than that in natural precipitation with greater irrigation requirement, and water supply in this period has greater importance for both agriculture and ecology development.

       

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