EVALUATION OF SOIL MOISTURE - PRECIPITATION FEEDBACK USING REMOTE SENSING DATA

The interplay of soil moisture and precipitation strongly affects the terrestrial water and energy cycles. The interaction between soil moisture and precipitation is complex, varying regionally in correlation direction (i.e., positive/negative) and magnitude (i.e., weak/strong). In this study, we utilized the near-global soil moisture estimates and precipitation measurements from Soil Moisture Active Passive (SMAP) and Tropical Rainfall Measuring Mission (TRMM), respectively, to investigate the co-variation of soil moisture and precipitation regionally, as a function of climate regimes and ecosystem types. We apply information on climate regimes and land cover to provide insights about correlation strength of soil moisture and precipitation. The results indicate that most of the globe has a moderate to strong positive correlation of SMAP soil moisture and TRMM precipitation data during the study period. In relation to climate regimes, soil moisture and precipitation have stronger correlations in arid or cold regions, and weaker correlations in humid, temperate locations. As for land cover, soil moisture and precipitation have stronger correlations in regions of limited vegetation, whereas forests and densely vegetated regions have weaker correlations. While remotely sensed soil moisture data are less reliable in dense vegetation, these results confirm that drier and less vegetated climate show a highly linear relationship between soil moisture and precipitation.