Estimation of moisture availability over the Liudaogou river basin of the Loess Plateau using new indices with surface temperature
Estimation of moisture availability over the Liudaogou river basin of the Loess Plateau using new indices with surface temperature
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DOI：
10.1016/j.jaridenv.2006.12.021
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发表时间：
2007-07-01
影响因子：
2.7
通讯作者：
Kimura, R.
中科院分区：
文献类型：
--
作者：
Kimura, R.
本研究介绍了地表湿度状况估计指数的发展，旨在采用比以前的指数更机械的方法。可用水分 (m(a)) 计算为实际蒸散量 (ET) 与参考蒸散量 (ET0) 的比率，并使用两个新开发的指数估算中国黄土高原流域的土壤含水量。根据卫星获得的表面温度以及根据气象数据估计的空气动力学最低和最高表面温度计算出修正的温度-植被干燥指数（MTVDI）。 MTVDI 很好地对应了不同土地利用区域的 m(a) 季节变化，尤其是草地区域。根据 MTVDI 与归一化差分植被指数 (NDVI) 之间的关系（MTVDI-NDVI 三角形空间）推导出湿边指数，该空间是通过将 MTVDI 绘制为 NDVI 的函数来实现的。湿边指数显示了流域内各种地表和土壤含水量与m(a)的关系。然而，我们得出的结论是，需要更广泛的植被覆盖和土壤湿度含量来计算有意义的湿边指数。这两个指数具有可以定性估计地表水分状况的优点。它们可以用作干旱度和/或干旱指数。 (C) 2007 Elsevier Ltd. 保留所有权利。
This study presents developments of indices for Surface moisture condition estimations aiming at a more mechanistic approach compared to previous indices. Moisture availability (m(a)) calculated as the ratio of actual evapotranspiration (ET) to reference evapotranspiration (ET0), and soil water content were estimated over a river basin oil the Loess Plateau of China using two newly developed indices. A modified temperature-vegetation dryness index (MTVDI) was calculated from satellite-derived surface temperature, and aerodynamic minimum and maximum surface temperatures estimated from meteorological data. MTVDI corresponded well to seasonal variations of m(a) over an area of varied land use, and especially well in areas of grassland. A wet-edge index was derived front the relationship between MTVDI and the normalized differential vegetation index (NDVI), the MTVDI-NDVI triangle space, which is achieved by plotting MTVDI as a function of NDVI. The wet-edge index showed the relationship to m(a) of various land surfaces and soil water contents in the river basin. However, we concluded that a wider range of vegetation cover and soil moisture content were needed to calculate a meaningful wet-edge index. These two indices have advantages that can estimate surface moisture condition qualitatively. They can be used as aridity and/or drought indices. (C) 2007 Elsevier Ltd. All rights reserved.