Biparabolic NDVI-TS Space and Soil Moisture Remote Sensing in an Arid and Semi arid Area

. Normalized difference vegetation index (NDVI) and land surface temperature (T-s) data from the multitemporal Moderate Resolution Imaging Spectroradiometer (MODIS) were used to analyze the NDVI-T-s space. Unlike the traditional triangular or trapezoidal NDVI-T-s space, the NDVI-T-s space in this study was biparabolic when NDVI values below 0.15 were included, describing areas that are vegetated but have low biomass due to arid conditions. Moreover, the NDVI-T-s biparabolic space is slightly better than the NDVI-T-s triangular space at discerning soil moisture (validation at a 10-cm depth). Linear relationships exist between TVDIC obtained from the NDVI-T-s biparabolic space and relative soil moisture with R-2 > 0.28, while correlation coefficient between TVDIT obtained from the triangular NDVI-T-s space and relative soil moisture is R-2 > 0.08. The soil moisture situations in Henan Province from February 26, 2011 to May 16, 2011 and in the Shendong mining area on October 8, 2010 were evaluated based on the temperature vegetation dryness index (TVDI) obtained from the NDVI-T-s biparabolic space. Moreover, the general spatiotemporal features of soil moisture conditions in Henan Province and the Shendong mining area were revealed.