Abstract: The SMAP (Soil Moisture Active Passive) mission provides global surface soil moisture product at 36 km resolution from its L-band radiometer. While the coarse resolution is satisfactory to many applications there are also a lot of applications which would benefit from a higher resolution soil moisture product. In this paper the SMAP radiometer-based soil moisture product was downscaled to 1 km using MODIS (Moderate Resolution Imaging Spectroradiometer) data, and validated against airborne dat…