Satellite-derived vegetation temperature condition index to infer root zone soil moisture in semi-arid province of Rajasthan, India

Soil moisture is one of the key state variable to regulate the water and energy budgets at the soil-plant-atmosphere continuum. This study demonstrates the utility of Vegetation Temperature Condition Index (VTCI), developed from interpretation of NDVI-Ts space using MODIS, to estimate soil moisture status at a spatial resolution of 1-km in Rajasthan province. The key findings reveal that VTCI at 1-km resolution and computed for the whole image (Method-1) was found to be more representative of the average profile soil moisture condition than the other methods. Statistical regression between VTCI and in-situ volumetric soil moisture for the surface and at depths of 15, 30 and 45 cm for the prominent crops in Eastern Rajasthan showed a strong relation (R-2 = 0.63, p-value <0.01). Thus, it is suggested that VTCI is useful to infer soil moisture beneath the surface over semi-arid areas for agricultural drought assessment.