Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture (L3, Passive)" layer displays a daily global composite of surface soil moisture in cm3/cm3 derived from the Single Channel Algorithm V-Pol (SCA-V), the baseline soil moisture algorithm, for the 6:00 a.m. descending half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. The variation in the intensity of this radiation depends on the dielectric properties and temperature of the target medium, which for the near surface soil layer is a function of the amount of moisture present.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate. The imagery resolution is 2 km and sensor resolution is 36 km. The temporal resolution is daily.
References: SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture
Data field: soil_moisture