Ongoing research project |

Soil Moisture and Ocean Salinity (SMOS)

SMOS is the second Earth Explorer Opportunity mission (launched in November 2009) developed as part of the European Space Agency (ESA) Living Planet programme. The SMOS mission provides two-dimensional interferometric radiometer measurements of L-band (1.4 GHz) brightness temperature from a satellite in polar orbit. At this frequency the atmosphere is almost transparent and surface emission is strongly related to soil moisture over continental surfaces, salinity and surface state of the oceans, and to the thickness of sea ice.

The key objectives of the SMOS mission are to:

  • Improve our understanding of the global water cycle.

  • Contribute to the improvement in weather and seasonal-climate forecasting.

ECMWF plays a major role in developing and implementing the use of SMOS brightness temperature data in NWP models. ECMWF’s contribution to the SMOS mission include:

  • Maintenance and operations of data monitoring system for the SMOS near real time product to provide a timely quality check for ESA and the SMOS Expert Suport Laboratories (ESL)

  • SMOS Neural Network NRT Soil moisture product operations and dissemination to the European Space Agency

  • SMOS Neural Network soil moisture production for data assimilation purpose and assimilation in the ECMWF NWP system.

  • Provision of ECMWF forecast as SMOS Auxilliary Files (ADFs) to ESA and support to SMOS ESL Teams

One main component of the monitoring is the observation operator that transforms model fields (soil moisture and ocean salinity) into observation equivalent (brightness temperatures).

To this end the CMEM (Community Microwave Emission Modelling Platform) has been developed at ECMWF. More information on ECMWF SMOS.

Furthermore, research continues towards assimilation of SMOS brightness temperature data in ECMWF's global NWP system.

The usefulness of SMOS data for measuring the thickness of thin sea ice and strong winds over the ocean is also being investigated.

SMOS activities at ECMWF were conducted in the context of the ESA SMOS Data Assimilation Study projects (2007-2010 and 2010-2018), and the SMOS ESL project currently in Phase 1 (2020-2021).

European Space Agency