The NASA Soil Moisture Active Passive (SMAP) Mission Status and Early Results

NASA's Soil Moisture Active Passive (SMAP) mission was launched on January 31, 2015. SMAP provides high-resolution, frequent revisit global mapping of soil moisture and freeze/thaw state based on coincident L-band radiometer and L-band radar measurements. The simultaneous radar and radiometer measurements are separately and in combination used to retrieve global soil moisture maps with 0.04 volumetric soil water content [m3/m3] (1 sigma) accuracy. The radiometer has advanced capability to detect Radio Frequency Interference (RFI). The radiometer hardware and processing software are also designed to mitigate some RFI contamination. As a result the land coverage and accuracy of the surface soil moisture retrievals are greatly enhanced. The instrument measurements also allow the binary detection of surface freeze/thaw state. The instruments use a common 6 m mesh deployable offset fed reflector antenna that rotates at about 14.6 rpm to provide a 1000 km measurement swath that enables global coverage every 2-3 days. In this presentation the status of the SMAP observatory and early results based on the science data products will be presented. The early period of science data acquisition also contains the intense calibration and validation phase. Early beta geophysical data products are now available. The data are public and accessible at designated open data archives (National Snow and Ice Data Center in Boulder, CO and the Alaska Satellite Facility in Fairbanks, AK). The primary science goal of SMAP is to provide new perspectives on how the three fundamental cycles of the Earth system, the water, energy and carbon cycles, are linked together over land. Soil moisture is the key variable that links the three cycles and makes their co-variations synchronous in time. SMAP data products also have several key practical applications that affect society through applied science. These include Numerical Weather Prediction, seasonal climate outlook, operational flash-flood and main-stem flood forecasting, and drought monitoring among others. The mapping low-frequency microwave radar and radiometer measurements are also used in development of information on sea ice, ocean surface winds and sea surface salinity. Examples of these retrievals are included in this presentation.