Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/20/2007
Publication Date: 12/9/2007
Citation: McKee, L.G., Jackson, T.J., Bindlish, R., Tao, J. 2007. Vegetation water content retrievals for NAFE06 and CLASIC [abstract]. EOS Transactions, American Geophysical Union, Fall Supplements. 88(52):H31D-0630.
Technical Abstract: Vegetation water content (VWC) is a valuable input to many microwave based soil moisture retrieval algorithms. Previous research, both theoretical and experimental, has established that VWC can be estimated using multispectral remote sensing. There are limits on the reliability of these methods that are related to canopy characteristics. For some crops index based techniques typically saturate before peak VWC occurs. Therefore, a careful evaluation using validation data is useful, especially in an intensive field campaign. As part of NAFE06 and CLASIC, ground based VWC sampling was conducted in conjunction with surface reflectance and Leaf Area Index (LAI) measurements. These data were used to establish crop/cover condition dependent relationships between the Normalized Difference Water Index (NDWI) and VWC. In order to apply these relationships over larger regions it was also necessary to develop land cover classifications using satellite data that incorporated the temporal changes that occurred during the study (i.e. flooding of rice fields). This was accomplished using multiple Landsat Thematic Mapper or ASTER images and a decision tree classifier. The NDWI relationships were applied to the available vegetation index images to generate VWC.