Characterizing satellite-derived soil moisture and its relationship with rainfall over India

Understanding the spatial and temporal variations of soil moisture is important since the feedback between soil moisture and precipitation is a key control of the climate. This is also important as soil moisture data is a key input in regional climate models. The inter-annual and inter-decadal variability of soil moisture has been investigated here using the European Space Agency's Climate Change Initiative active and passive combined soil moisture product over different climate regimes of India. The observed soil moisture and rainfall are positively correlated and their relationship in this study suggests that both positive and negative feedback occur. The analysis showed an increasing soil moisture trend with a significant increase in the monsoon and autumn seasons for the past two decades over central India, where the frequency of extreme precipitation increased in the same period. An overall increase in soil moisture over the western arid region is also significant. A decreasing trend in soil moisture prevailed throughout the monsoon season over eastern India, where monsoon depressions make landfall, signalling the recent climate trends over the Indian subcontinent.