Retrieving soil moisture for non-forested areas using PALS radiometer measurements in SMAPVEX12 field campaign
Retrieving soil moisture for non-forested areas using PALS radiometer measurements in SMAPVEX12 field campaign
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DOI：
10.1016/j.rse.2016.06.001
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发表时间：
2016-10
影响因子：
13.5
通讯作者：
A. Colliander;E. Njoku;T. Jackson;S. Chazanoff;H. Mcnairn;J. Powers;M. Cosh
中科院分区：
文献类型：
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作者：
A. Colliander;E. Njoku;T. Jackson;S. Chazanoff;H. Mcnairn;J. Powers;M. Cosh
本文利用L波段亮温数据，对不同条件和不同土地覆盖类型下的表层土壤水分进行了反演研究。研究的重点是2012年在加拿大马尼托巴省南部进行的SMAPVEX12(土壤湿度主动被动验证试验2012)野外试验期间收集的PALS(被动主动L波段系统)辐射计数据。试验区既有高粘粒含量的农田，也有沙质土壤的农田和草地。对于这些特定的土地类型，检索算法被参数化。该反演算法的公式是基于传统的表面散射假设。基于这一数据集，我们发现对于粘质农田，表面散射假设是不充分的，并且对于沙质土壤，该算法需要进行重大调整。开发了基于经验的参数，用于在这些条件下反演土壤水分。我们还将该参数化算法应用于整个实验区的土壤水分反演。我们发现，子网格建模的使用将检索性能提高到了令人满意的水平，尽管遇到了具有挑战性的土地类型。
In this paper, soil moisture retrievals of surface soil moisture was investigated using L-band brightness temperature under diverse conditions and land cover types. The study focused on the PALS (Passive Active L-band System) radiometer data collected during the SMAPVEX12 (Soil Moisture Active Passive Validation Experiment 2012) field experiment which took place in southern Manitoba, Canada in 2012. The experiment domain covers croplands with high clay content as well as croplands and grasslands with sandy soils. A retrieval algorithm was parameterized for these specific land types. The formulation of the retrieval algorithm is based on a traditional surface scattering assumption. Based on this data set we found that for the clayey croplands the surface scattering assumption is inadequate, and that the algorithm needed significant tuning for the sandy soils. Empirically-based parameters for retrieving soil moisture under these conditions were developed. We also applied the parameterized algorithm to the retrieval of soil moisture for the entire experiment domain. We found that the use of sub-grid modeling improves the retrieval performance to a satisfactory level despite the challenging land types encountered.