Spaceborne soil moisture estimation at high resolution: a microwave-optical/IR synergistic approach
Spaceborne soil moisture estimation at high resolution: a microwave-optical/IR synergistic approach
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DOI：
10.1080/0143116031000156837
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发表时间：
2003-11-01
影响因子：
3.4
通讯作者：
Ardanuy, P
中科院分区：
文献类型：
--
作者：
Chauhan, NS;Miller, S;Ardanuy, P
评价了一种利用卫星微波和光学/红外（IR）数据以高分辨率估算土壤湿度的方法。这种方法可应用于可见光/红外成像仪辐射计传感器套件和锥形扫描微波成像仪/探测器（CMIS）获得的数据，计划在2009-2010年的时间框架下发射的国家极轨业务环境卫星系统（NPOESS）。土壤水分估算方法分为两个步骤。在第一步中，采用被动微波遥感技术在低分辨率（类似于25 km）下估计土壤水分。这涉及到使用一个简化的辐射传输模型来反演双偏振微波亮度温度。在第二步中，微波导出的低分辨率土壤水分与场景光学/IR参数相关联，例如归一化差异植被指数（NDVI），地表温度和地表温度（LST）。这种联系是基于“通用三角形”的方法，将地表参数与土壤湿度联系起来。光学/红外参数具有高分辨率（类似于1公里），但为了建立联系模型，将其汇总到微波分辨率。与高分辨率的植被指数，地表温度和LST的联动模型，然后使用分解成高分辨率的土壤水分微波土壤水分。该技术适用于从特殊传感器微波成像仪（SSM/I）和高级甚高分辨率辐射计（AVHRR）获得的南部大平原（SGP-97）的实验在俄克拉荷马州在1997年6月7月的数据。对估计过程进行的误差预算分析表明，土壤水分估计的均方根误差为5%的顺序。高分辨率的土壤水分预测结果与低分辨率结果在量级和时空格局上都相当吻合。高分辨率的结果进行了比较，在原位（0-5厘米深）点测量。虽然趋势相似，但两种情况下的土壤湿度估计值不同。还讨论了卫星测得的土壤湿度与现场点测量值的比较问题。
An approach is evaluated for the estimation of soil moisture at high resolution using satellite microwave and optical/infrared (IR) data. This approach can be applied to data acquired by the Visible/Infrared Imager Radiometer Sensor Suite (VIIRS) and a Conical Scanning Microwave Imager/Sounder (CMIS), planned for launch in the 2009-2010 time frame under the National Polar-Orbiting Operational Environmental Satellite System (NPOESS). The approach for soil moisture estimation involves two steps. In the first step, a passive microwave remote sensing technique is employed to estimate soil moisture at low resolution (similar to25 km). This involves use of a simplified radiative transfer model to invert dual-polarized microwave brightness temperature. In the second step, the microwave-derived low-resolution soil moisture is linked to the scene optical/IR parameters, such as Normalized Difference Vegetation Index (NDVI), surface albedo, and Land Surface Temperature (LST). The linking is based on the 'Universal Triangle' approach of relating land surface parameters to soil moisture. The optical/IR parameters are available at high resolution (similar to1 km) but are aggregated to the microwave resolution for the purpose of building the linkage model. The linkage model in conjunction with high-resolution NDVI, surface albedo and LST is then used to disaggregate microwave soil moisture into high-resolution soil moisture. The technique is applied to data from the Special Sensor Microwave Imager (SSM/I) and Advanced Very High Resolution Radiometer (AVHRR) acquired for the Southern Great Plains (SGP-97) experiment conducted in Oklahoma in June July 1997. An error budget analysis performed on the estimation procedure shows that the rms error in the estimation of soil moisture is of the order of 5%. Predicted soil moisture results at high resolution agree reasonably well with low resolution results in both magnitude and spatio-temporal patterns. The high resolution results are also compared with in situ (0-5 cm deep) point measurements. While the trends are similar, the soil moisture estimates in the two cases are different. Issues involving comparison of satellite derived soil moisture with in situ point measurements are also discussed.