SMOS

SMOS, or Soil Moisture and Ocean Salinity, is a European Space Agency Earth observation mission designed to produce global maps of soil moisture and sea surface salinity. By providing measurements of soil moisture and ocean salinity, SMOS supports climate research, weather forecasting, and water resource management, and contributes to understanding the role of water cycles in Earth systems.

It carries the MIRAS instrument, a passive microwave radiometer operating in the L-band around 1.4 GHz. MIRAS uses interferometric techniques to measure brightness temperatures over land and ocean, enabling retrievals of soil moisture and salinity from the observed radiances.

SMOS was launched in 2009 and placed into a sun-synchronous low Earth orbit at roughly 700 kilometers altitude. The mission is operated by ESA with partners including CNES. Data products include soil moisture maps, ocean salinity fields, brightness temperature data, and auxiliary data used to calibrate and interpret observations.

Data are provided to the international science community and are archived and distributed through ESA's portals, enabling researchers to examine hydrologic and oceanographic processes, validate models, and support numerical weather prediction and climate studies. Since its launch, SMOS has contributed to global coverage of surface water properties and has informed ocean and land surface research, with ongoing data collection and calibration efforts continuing under ESR-supported programs.