Soon 8 candles for SMOS!!!!! (5/8)

Category : CATDS, L2, L3, Model, Ocean

Another post from Jacqueline…and Jérôme

Water cycle in the Bay of Bengal

J. Vialard , S. Marchand et al. (LOCEAN)

The Bay of Bengal receives large amounts of freshwater from the Ganges-Brahmaputra river and monsoonal rainfall. The associated very low surface salinities induce a very stable stratification that inhibits vertical mixing of heat and nutrients. This has strong consequences for the climatological rainfall, intensification of tropical cyclones and ocean productivity in this region.

Available climatologies based on in situ data (e.g. World Ocean Atlas, top row) do not resolve the very strong horizontal gradients in this region. SMOS data (middle row) reveal that the narrow, coastal-trapped East-Indian Coastal Current transport the freshwater plume of Ganges-Brahmaputra along the Indian coast from October to December, resulting in large horizontal gradients (typically ~5 pss between coastal and offshore waters). The 8 years-long time series reveals a strong inter-annual variability of the freshwater plume southward extent, which can be related to Indian Ocean climate variability.


Caption: World ocean atlas (derived from in situ data, top row) and SMOS (middle row) (SSS climatology (altimeter-derived surface current climatology are overlaid on both panels). (Bottom row) Latitude-time section of SMOS SSS along the east coast of India. The southward extent of the freshwater plume varies depending on Indian Ocean climate variability associated with the Indian Ocean Dipole (Akhil et al. in prep.). (SMOS CATDS CPDC L3Q SSS)

To know more about associated work:

Akhil, V.P., F. Durand, M. Lengaigne, J. Vialard, M.G. Keerthi, V.V. Gopalakrishna, C. Deltel, F. Papa and C. de Boyer Montégut, 2014: A modeling study of the processes of surface salinity seasonal cycle in the Bay of Bengal, J. Geophys. Res. Oceans, 119, doi:10.1002/2013JC009632.

Akhil, V. P., M. Lengaigne, J. Vialard, F. Durand, M. G. Keerthi, A. V. S. Chaitanya, F. Papa, V. V. Gopalakrishna, and C. de Boyer Montégut, 2016a: A modeling study of processes controlling the Bay of Bengal sea surface salinity interannual variability, J. Geophys. Res. Oceans, 121, 8471–8495, doi:10.1002/2016JC011662.

Akhil, V.P., M. Lengaigne, F. Durand, J. Vialard, V.V. Gopalakrishna, C. de Boyer Montégut and J. Boutin, 2016b: Validation of SMOS and Aquarius remotely-sensed surface salinity in the Bay of Bengal, IJRS, 37,  doi: 10.1080/01431161.2016.1145362

Boutin, J., J.L. Vergely, S. Marchand, F. D’Amico, A. Hasson, N. Kolodziejczyk, N. Reul, G. Reverdin (2017), Revised mitigation of systematic errors in SMOS sea surface salinity: a Bayesian approach, Remote Sensing of Environment, in revision.

Chaittanya, A.V.S., M. Lengaigne, J. Vialard, V.V. Gopalakrishna, F. Durand, Ch. Krantikumar, V. Suneel, F. Papa and M. Ravichandran, 2014: Fishermen-operated salinity measurements reveal a “river in the sea” flowing along the east coast of India, Bull. Am. Met. Soc., 95, 1897-1908.

Fournier, S., J. Vialard, M. Lengaigne, T. Lee, M.M. Gierach, A.V.S. Chaitanya, Unprecedented satellite synoptic views of the Bay of Bengal “river in the sea”, 2017: J. Geophys. Res., in (minor) revision.

New salinity products are available at CATDS!

Category : CATDS, L3, L4, Ocean

Dear CATDS user,

New salinity products are available at CATDS. A new correction for systematic errors (land-sea and seasonal-latitudinal ) has been implemented in CATDS CPDC and in CATDS CEC LOCEAN.

Concerning CATDS CPDC, a RE05 reprocessing of ocean salinity is available from January 2010 to March 2017; the operational processing has been updated accordingly. Binned maps at usual spatial and temporal resolution are available. The SMOS SSS corrected for systematic errors are in MIR_CSQ3 files; non corrected SMOS SSS remain available in MIR_CSF3 files. The corrected product is limited to 45N-47S, the correction remaining uncertain at higher latitudes. A new ATBD is available at
You can download this product from the usual ftp site :

Concerning CATDS CEC-LOCEAN, 9-day and 18-day products sampled at 25km resolution are provided every 4 days. They cover all latitudes from January 2010 to December 2016 (see further description in the documentation at
A validation of these products has been presented at EGU (see poster at
You can download this product from the usual ftp site :

Best regards

The CATDS Team

What’s next?

Category : Data, Satellite

Dear reader of this blog.

As you are well aware SMOS and SMAP (and Aquarius for that matter) are delivering excellent data, demonstrating every day the usefulness and uniqueness of L Band data for monitoring certain facets of our planet. Moreover, many operational or pre-operational applications are emerging. The sad thing is that our dear satellites are like us, they don’t get younger with time. … and no follow on L Band radiometers are currently decided. We are thus facing a severe data gap if a follow-on is not very soon set up.

Actually the situation is getting somewhat critical and i am convinced we should get moving quite soon on this critical issue.

I thought that we could use this forum to highlight the areas the expression of needs for L band radiometry. If you have interesting elements let me know!

In the mean time see 6 years of global soil moisture as prepared by Ali Mahmoodi with 6 years of  SMOS data.anim-sm-6y

Monthly evolution of soil moisture for teh first 6 years of SMOS (2010-2015)


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) »

download wordpress themes