Quantification and Correction of SMAP Soil Moisture Retrieval Biases Induced by Subpixel Moisture and Texture Heterogeneity Over China (opens in new tab)

Surface soil moisture (SSM) plays a vital role in regulating terrestrial water and energy exchanges. However, SSM retrievals from passive microwave (PMW) sensors such as Soil Moisture Active Passive (SMAP) are theoretically biased by subpixel soil heterogeneity, particularly the combined variability of soil moisture and soil texture within coarse-resolution footprints. This study investigates and corrects these heterogeneity-induced biases (HBs) in SMAP SSM products. Using a 1-km downscaled S...