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

SMOS helps discriminating water sources in cold seas

Category : L2, Ocean

Discriminating water sources from space in the Arctic Ocean: A case study for the southern Beaufort Sea using MODIS ocean color and SMOS salinity data

A recent paper by Matsuoka et al. (2016), using SMOS ESA L2 SSS, found nice correlations between the interannual variability of SMOS SSS and ocean color CDOM (see fig 1 and 2 below) in the Mackenzie river mouth. Using this region as a case study, they derive an algorithm using this two sets of data for getting reasonable fractions of river water. As stated by the authors ‘Application of this algorithm may lead to the discrimination of water sources in the surface layer of the Arctic Ocean in various environments where seawater, ice melt water, and river water are intermingled,which might be useful to improve our understanding of physical and biogeochemical processes related to each water source’.


Fig.1 : Satellite images of CDOM absorption coefficient at 443 nm [aCDOM(443),m−1] using MODIS ocean color data in July to August 2010 to 2012 (from Matsuoka et al. (2016))


Fig. 2 : Same as Fig. 1 for SMOS SSS (from Matsuoka et al. (2016)).

Atsushi Matsuoka, Marcel Babin, Emmanuel C. Devred, A new algorithm for discriminating water sources from space: A case study for the southern Beaufort Sea using MODIS ocean color and SMOS salinity data, Remote Sensing of Environment, Volume 184, October 2016, Pages 124-138, ISSN 0034-4257, (//

Workshop announcement: « measuring high-wind speeds over the ocean »

Category : L2, L3, Ocean

On behalf of the organizing committee, I would like to draw your attention on the SMOS+STORM ESA project workshop

International workshop on measuring high-wind speeds over the ocean

15-17 November 2016, Met Office, Exeter


A three-day workshop on the science and applications of ocean surface winds, with a focus on measuring high or extreme wind speeds. The workshop will be held at the Met Office headquarters in the cathedral city of Exeter.

Topics will include:

  • Satellite measurement techniques including new capabilities from SMOS, SMAP and AMSR2 sensors
  • Ground and airborne measurements
  • Core/operational applications and challenges e.g. hurricane/extreme forecasting, storm surges, waves
  • Air-sea applications and challenges e.g. seasonal/climate, upper ocean dynamics, air-sea interaction, biogeochemistry
  • Numerical Weather Prediction (NWP) applications
  • Numerical Ocean Prediction (NOP) applications

Organisers: Pete Francis (Met Office), James Cotton (Met Office), Nicolas Reul (IFREMER), Craig Donlon (ESA)

Further information on how to register for the workshop and submit an abstract and preliminary program is available from the link below:

Please find also attached the workshop flyer.


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