STOP PRESS!! The first CCI+SSS maps are now available

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From Jacqueline Boutin at LOCEAN

The first version of satellite Sea Surface Salinity (SSS) maps produced by the ESA CCI (Climate Change Initiative) SSS project by combining SMOS-CATDS, AQUARIUS and SMAP SSS over the 2010-2018 period are now available. Systematic differences between SSS obtained from the various instruments and under various geometries have been homogenized  using a methodology similar to the one developed and implemented at CATDS (Centre Aval de Traitement des Données SMOS).

See more on data description and access here.

You may also see the ESA announcement there.


SSS maps as derived from SMOS+ AQUARIUS (2012) and from SMOS+SMAP (2017) : see in particular the interannual variation of the SSS in the Amazon plume, off the Rio De La Plata and the Mississippi river plumes.

Announcing a special Issue « Soil Moisture and Ocean Salinity: Water Cycle Components from Decadal SMOS Observations »

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Special Issue « Soil Moisture and Ocean Salinity: Water Cycle Components from Decadal SMOS Observations »

is open for submissions

The Soil Moisture and Ocean Salinity (SMOS) satellite, launched in November 2009, is specifically designed to provide data regarding soil moisture and vegetation water content over continental surfaces as well as on ocean salinity. These features are key components of the water cycle, and their characterization at large scale is essential for weather and climatic studies. The SMOS instrument—an interferometer—measures the Earth surface’s passive microwave emission at L-band (1.4 GHz). It provides the brightness temperature at several angles and two polarizations (H and V polarization) with an average resolution of 40 km. Complete coverage of Earth is achieved in three days with data acquired at two daily timepoints of 6 am and 6 pm (local time).

After a decade of collecting SMOS data, the assimilation of these data have led to the development of numerous products linked with the global water cycle, such as water fraction, freeze/thaw, thin sea ice, root zone soil moisture, drought indices at low and high spatial resolution, flood risk indices, and improved precipitation.

This Special Issue solicits original manuscripts on innovative research—from work based on SMOS data to hydrological studies. We welcome contributions using SMOS data to examine hydrological changes during the last 10 years. The potential topics of this Special Issue include, but are not limited to:

  • Decadal observations on global and/or regional water cycle components using SMOS data;
  • Detection of hydrological extreme from SMOS data;
  • New hydrological products based on SMOS data;
  • Fusion of SMOS data and other(s) sensor(s) for hydrological purposes;
  • Coupling SMOS observations and modeling in hydrology.

Dr. Marie Parrens
Dr. Ahmad Al Bitar
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Remote Sensing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI’s English editing service prior to publication or during author revisions.


  • SMOS
  • hydrology
  • large scale
  • decadal observations
  • soil moisture
  • root zone soil moisture
  • freeze
  • vegetation water content
  • water fraction
  • L-band

SMOS-L4 precipitation product available on CATDS database (PrISM)

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From Thierry Pellarin IGE

Surface soil moisture intrinsically contains information on previous rain event. Different research teams (W. Crow (USDA, US), L. Brocca (IRPI, Italy), T. Pellarin (IGE, France), N. Wanders (Utrecht, NL)) investigated the way to use satellite soil moisture measurements to derive a precipitation product. At IGE (Grenoble Alpes University), a methodology based on the assimilation of SMOS measurement in a simple soil moisture – precipitation model was developed: the PrISM methodology (Precipitation Inferred from Soil Moisture).


Figure: Evaluation of PrISM precipitation products over 20 raingauge stations in Burkina Faso. PrISM is applied to correct for CMORPH, PERSIANN and TRMM-RT products using SMOS-L3SM.

The illustration gives an overview of the performance of three real-time satellite precipitation products (CMORPH, PERSIANN and TRMM-RT) versus SMOS-PrISM products over 20 raingauge stations in Burkina Faso (2012) in term of correlation, RMSE and bias (red boxes). The blue boxes (PrIMS products) indicate the improvement of the performances of the three real-time satellite precipitation products due to SMOS soil moisture information.

PrISM precipitation products (0.25°, 3 hours) are available on CATDS from 2010 to 2017, for Africa and Australia. PrISM was funded by CNES (TOSCA) and ESA (SMOS+RAINFALL ESA/AO/1-7875/14/I-NC).

Data is available on CATDS and more specifically here and more details on the product are given here

SMOS data is now integrated into ECMWF’s forecasting system!

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Great news!

As of last Monday (June 11, 2019) the European Centre for Medium range Weather Forecast (ECMWF) is using SMOS in its forecasting system (46R1)!

Since its launch in 2009, the Soil Moisture and Ocean Salinity (SMOS) mission  made by ESA CNES and CDTI has been providing global observations of L band emissions from Earth’s surface, providing information on, but not limited to, soil moisture, vegetation optical thickness, thin sea ice, freeze thaw, and ocean salinity – all very major components of the water cycle.

Accurate weather forecasts are paramount for both commercial and leisure activities. ECMWF is the leading agency to provide global accurate weather forecasts. Its Integrated Forecasting System (IFS), a gigantic numerical weather prediction model, provides weather predictions 24 hours a day, seven days a week. To do so the system ingests lots of data but the key is to get data into the IFS in the so called near real time (NRT ) .i.e., less than 3 hours after sensing. which is not necessarily easy with satellite data requiring lost of processing.


Fig1: Impact of assimilation SMOS SM NN and screen variables on weather forecasts at ECMWF on air temperature at 850 hPa for different forecast periods (July September period).eImprovements are in blue.

To overcome this difficulty, LERMA and CESBIO jointly worked on a faster retrieval approach relying on machine learning through the use of Neural Networks. It was adapted to ECMWF requirements  by N Rodriguez Fernandez et al., to generate the information needed for operational forecasts, and after 15 years or so of efforts, the SMOS data is used in 24/7 operations which is a major achievement.


Fig 2 SMOS derived soil moisture using neural networks

So far, only SMOS measurements over land are being used to support general weather forecasts. Considering SMOS provides information in all weather conditions, SMOS also delivers new information for tracking hurricanes or improving rainfall estimates from satellite, for monitoring thin sea ice or freeze thaw, for monitoring root zone soil moisture and delivering drought indices etc (see previous posts on this blog!).

So far, SMOS is the only Earth explorer satellite providing measurements operationally for global medium-range weather forecasts. But is was not even considered for Copernicus expansion mission…Nevertheless we are keeping busy and a phase A for the SMOS improved follow on: SMOS High Resolution or SMOS HR is starting at CNES in an international collaboration scheme. The Goal is to have by 2026 a 10 km resolution L band radiometer… Stay tuned!

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