Vegetation water content retrieval using MERIS and AATSR data over the Loess Plateau

Vegetation water content is an important indicator of the degree of stress experienced by plants. This paper explored the potential of using the remote sensing data of MERIS (Medium Resolution Imaging Spectrometer) and AATSR (Advanced Along-Track Scanning Radiometer) collected during the Loess Plateau land surface process field Experiment 2005 (LOPEX05) to map and monitor vegetation water content for corn canopies. By comparing with the daily ground observation to validate the satellite reflectance data, we established relationships between the vegetation water content and satellite remotely sensed indices. The two indices studied were the NDVI (Normalized Different Vegetation Index) from MERIS and the NDWI (Normalized Different Water Index) from AATSR. We used the daily ground observation to demonstrate that the NDVI was saturated during the study period while the NDWI continued to reflect the changes in VWC. We found that NDWI, based on near infrared channel (0.855-0.875 mu m) and short wave infrared wavelength channel (1.58-1.64 =mu m), is suggested to be more suitable and robust approach for retrieval of vegetation water content. The proposed method was validated with experimental field data with biases that are 1.0314 kg/m(2) and 0.9413 kg/m(2) respectively. Therefore the NDWI was recommended to retrieval the vegetation water content.