Soon 8 candles for SMOS!! (4/8)

Category : CATDS, Cal/Val, Data, L2, Non classé, ground measurements

Today let’s have a look back on what was done over land… but remember: it is only a quick summary of part of the findings!!


Of course all the emphasis at the beginning was on the soil moisture retrievals over what as called « nominal surfaces », which meant land surface with moderate vegetation cover (fallow, crop land, savannah etc..) with all the cal val efforts related to it. For this in particular, several sites were dedicated to Cal Val (VAS in Spain, UDB in Germany, AACES/COSMOS/NAFE in Australia, and later HOBE in Denmark, with also sites in France, Poland, Finland, Tibet, etc…). We also relied heavily on the USDA so called « Watershed sites » and various sparse networks. Actually it is for SMOS that ESA and NASA decided to start the International Soil moisture Network.

lewis-faugaAACES 6MELBEX-II EMIRAD Installation 004LEWIS_3IMG_9674ELBARA-Sodankyla

Various pictures SMOSREX, AACES, VAS, Crolles, Mysore, Sodankylä …

Surprisingly enough we obtained good results almost immediately. But this was only the beginning as, in parallel, both level 1 and level 2 made significant progresses, leading to always improved retrievals. Actually with such fast progresses, it has always been a bit of a frustration to see people use not up to date products, as publications looking at SMOS data tended – for obvious reasons – to be a couple of version old (but generally failed to stipulate which version they were looking at!).

The most striking features of these always improved retrievals was, to me, the fact that the range of validity tended to regularly increase. Low to medium topography did not seem to a be a limitation, we managed to make sense in case of flooded areas (see for instance Mississipi floods) and we could get information in case of dense vegetation. The Tor Vergata University for instance related very quickly the vegetation depth to tree height and performed soil moisture retrievals under rainforest. No so accurate of course, but the tendencies are well depicted.


SMOS opacity vs tree height from ICESat for two season (Rahmoune et al)

The only trouble we had was that the vegetation optical depth was not as satisfactory as we would have expected. It remained noisy in spite of significant overall progresses. To address this problem and also to keep on improving our retrievals (parametrisations) INRA and CESBIO worked on a different approach, the so called SMOS-IC and, lo and behold, first results are rather amazing! We believe we have again struck gold. More about this in the near future!

To finish with the surface soil moisture and vegetation opacity retrievals, we were faced with the fact that the retrieval algorithm is not so fast and thus tests or re-processings are a lengthy and tedious. This was another motivation for SMOS-IC but we also wanted to go a step further and, as soon as enough data was acquired, we developed a global neural network retrieval scheme. It has since been implemented in ECMWF and delivers Soil moisture fields less than 3 hours of sensing, paving the way to many applications…. to be summarised soon: stay tuned!

Further reading

Fernandez-Moran, R.; Al-Yaari, A.; Mialon, A.; Mahmoodi, A.; Al Bitar, A.; De Lannoy, G.; Rodriguez-Fernandez, N.; Lopez-Baeza, E.; Kerr, Y.; Wigneron, J.-P. SMOS-IC: An Alternative SMOS Soil Moisture and Vegetation Optical Depth Product. Remote Sens. 2017, 9, 457.

Kerr, Y. H., et al. (2012), The SMOS Soil Moisture Retrieval Algorithm, IEEE Transactions on Geoscience and Remote Sensing, 50(5), 1384-1403, doi:10.1109/tgrs.2012.2184548.

Rahmoune, R., Ferrazzoli, P., Singh, Y., Kerr, Y., Richaume, P., Al Bitar,  A. SMOS Retrieval Results Over Forests: Comparisons With Independent Measurements. J-STARS ,2014

Rodriguez-Fernandez, N.J., Aires, F., Richaume, P., Kerr, Y.H., Prigent, C., Kolassa, J., Cabot, F., Jimenez, C., Mahmoodi, A., & Drusch, M. (2015). Soil Moisture Retrieval Using Neural Networks: Application to SMOS. Ieee Transactions on Geoscience and Remote Sensing, 53, 5991-6007

Vittucci, C., Ferrazzoli, P., Kerr, Y., Richaume, P., Guerriero, L., Rahmoune, R., & Laurin, G.V. (2016). SMOS retrieval over forests: Exploitation of optical depth and tests of soil moisture estimates. Remote Sensing of Environment, 180, 115-127


Category : CATDS, L3, Ocean

Dear  SMOS users,

All the SMOS L3 soil moisture, ocean salinity and common products, from January 2010 to April 2015, have been reprocessed. You can download those products from

a) CATDS with the usual procedure (if you do not have a password contact contact to get one) or

b) through the SIPAD interface (

Please NOTE :
- All the reprocessed products use the EASE2 grid.
- The CATDS processor’s version used is 300, which correspond to the DPGS version v620
- The reprocessed products are tagged RE04
- These reprocessed products are derived using the same algorithm as the one used in the CATDS real time processing, hence ensuring temporal continuity.
- A new RFI (radio frequency interference) probability product is available.

Very soon we will also make available 6 years of root zone soil moisture from SMOS

We appreciate your feed back so do not hesitate to contact us

Remember the SMOSDATA POLICY : The CATDS data are freely distributed. However, when using these data in a publication, we request that the following acknowledgement be given :
« These data were obtained from the « Centre Aval de Traitement des Données SMOS » (CATDS), operated for the « Centre National d’Etudes Spatiales » (CNES, France) by IFREMER (Brest, France) »

SMOS RSE special issue deadline postponed

Category : Cal/Val, Data, L1, L2, L3, L4, Model, Ocean, ground measurements

Dear colleague,

With regards to your potential contribution to the Special Issue on SMOS in Remote Sensing of Environment, we would like to notify you that the deadline for full paper submissions has been extended until 31st July 2015. Please be aware that this deadline change is final and no exceptions will be allowed after this date.

In case you have already submitted your paper, please disregard this message.

To submit your paper, please go to and select the option ‘submit paper’ from the menu bar near the upper left corner of the page. During the submission process, please make sure to select ‘SMOS 5 Years’ in the dropdown menu when choosing the article type, as demonstrated in the attached image.

Accepted papers will be published online as soon as possible following a final editing procedure by the Publisher. Once again, we encourage you to critically check your list of authors against the RSE guidelines on authorship ( to ensure appropriate representation of effort.

We look forward to receiving your contributions.

Yours sincerely,
Susanne Mecklenburg
On behalf of the editors for the Special Issue on SMOS in RSE

SMOS 3rd training course is in full swing

Category : Training

The SMOS training course (3rd edition) is currently taking place at the ESA centre of Villafranca (ESAC) in Spain.
18 students from 14 countries together with 4 spectators are currently being « initiated » to the SMOS data in the very nice facilities of ESAC


Ali presenting image reconstruction (picture by Beatriz)

The course is the third one and takes advantage of the release of the new version (V620) of the SMOS Data while covering both land and ocean science applications (see twitter account)

Next week, the Second post launch SMOS workshop will take place, also at ESAC. Stay tuned!

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