Fan, Lei; Xiao, Qing; Wen, Jianguang; Liu, Qiang; Tang, Yong; You, Dongqin; Wang, Heshun; Gong, Zhaoning; Li, Xiaowen (2015). Evaluation of the Airborne CASI/TASI Ts-VI Space Method for Estimating Near-Surface Soil Moisture. REMOTE SENSING, 7(3), 3114-3137.

Abstract
High spatial resolution airborne data with little sub-pixel heterogeneity were used to evaluate the suitability of the temperature/vegetation (Ts/VI) space method developed from satellite observations, and were explored to improve the performance of the Ts/VI space method for estimating soil moisture (SM). An evaluation of the airborne Delta T-s/Fr space (incorporated with air temperature) revealed that normalized difference vegetation index (NDVI) saturation and disturbed pixels were hindering the appropriate construction of the space. The non-disturbed Delta T-s/Fr space, which was modified by adjusting the NDVI saturation and eliminating the disturbed pixels, was clearly correlated with the measured SM. The SM estimations of the non-disturbed Delta T-s/Fr space using the evaporative fraction (EF) and temperature vegetation dryness index (TVDI) were validated by using the SM measured at a depth of 4 cm, which was determined according to the land surface types. The validation results show that the EF approach provides superior estimates with a lower RMSE (0.023 m(3)center dot m(-3)) value and a higher correlation coefficient (0.68) than the TVDI. The application of the airborne Delta T-s/Fr space shows that the two modifications proposed in this study strengthen the link between the Delta T-s/Fr space and SM, which is important for improving the precision of the remote sensing Ts/VI space method for monitoring SM.

DOI:
10.3390/rs70303114

ISSN:
2072-4292