A methodology for surface soil moisture and vegetation optical depth retrieval using the microwave polarization difference index
A methodology for surface soil moisture and vegetation optical depth retrieval using the microwave polarization difference index
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DOI：
10.1109/36.942542
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发表时间：
2001-08-01
影响因子：
8.2
通讯作者：
Walker, J
中科院分区：
文献类型：
--
作者：
Owe, M;de Jeu, R;Walker, J
提出了一种从卫星微波辐射计数据中反演地表土壤湿度和植被光学厚度的方法。该方法利用来自扫描多通道微波辐射计（SMMR）在伊利诺伊州几个试验场的历史6.6GHz水平（H）和垂直（V）极化亮温观测数据进行了测试。由于夜间地表温度估计更具稳定性，目前仅给出了使用夜间数据的结果。该方法使用辐射传输模型，通过非线性迭代优化程序同时求解地表土壤湿度和植被光学厚度。它假定散射反照率和粗糙度为已知常数，并且水平极化的植被光学厚度与垂直极化的相同。地表温度通过使用高频垂直极化亮温的程序得出。该方法不需要任何土壤湿度或冠层生物物理特性的实地观测用于校准，并且可应用于其他波长。结果与土壤湿度的实地观测以及来自光学传感器的卫星植被指数数据吻合良好。
A methodology for retrieving surface soil moisture and vegetation optical depth from satellite microwave radiometer data is presented. The procedure is tested with historical 6.6 GHz H and V polarized brightness temperature observations from the scanning multichannel microwave radiometer (SMMR) over several test sites in Illinois. Results using only nighttime data are presented at this time due to the greater stability of nighttime surface temperature estimation. The methodology uses a radiative transfer model to solve for surface soil moisture and vegetation optical depth simultaneously using a nonlinear iterative optimization procedure. It assumes known constant values for the scattering albedo and roughness, and that vegetation optical depth for H-polarization is the same as for V-polarization. Surface temperature is derived by a procedure using high frequency V-polarized brightness temperatures. The methodology does not require any field observations of soil moisture or canopy biophysical properties for calibration purposes and may be applied to other wavelengths. Results compare well with field observations of soil moisture and satellite-derived vegetation index data from optical sensors.