SMOS REPROCESSED Level 2 DATA (V6) now available

Category : Data, L1, L2, Ocean

Dear SMOS data user -

We would like to inform you that the reprocessed level 2 soil moisture and sea surface salinity data are now available on the new ESA SMOS Online Dissemination service:

This release aligns the Level 2 soil moisture and sea surface salinity data available operationally already since May 2015 with the reprocessed data archive: SMOS data users now have a complete v6 data set available.

The algorithm evolutions implemented in the v6 data set are described in the respective Algorithm Theoretical Baseline Documents (ATBDs) and in the read-me-first notes: We would like to encourage all users to familiarise themselves with the read-me-first notes before using the data.

The level 2 reprocessed data products are available on the new ESA SMOS Online Dissemination service accessible here ( The new service allows to access data by https and ftp/ftps transfer protocols for all registered ESA EO Single Sign-On (EO-SSO) users. The online service facilitates the data access with enhanced functionality for data navigation and selection by data type, acquisition time, geographical area and data format (i.e. ESA Earth Explorer (EEF) or NetCDF format).

SMOS level 1 brightness temperature data and  ECMWF auxiliary products are also available from the new ESA SMOS Online Dissemination service.

For further details on how to access the SMOS data  and how to register as ESA EO_SSO please

Kind regards

Susanne Mecklenburg


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) »

Research Engineer ‘Sea Surface Salinity retrieval from SMOS satellite measurements’

Category : L2, position opening

A research engineer position is opened at the Laboratoire d’Océanographie et du Climat – Expérimentation et Approches Numériques (LOCEAN)/ Institut Pierre Simon Laplace (IPSL), PARIS, starting as soon as possible. The position is for one year, likely renewable for 2 years.

Context :

The SMOS (Soil Moisture and Ocean Salinity) mission is the first satellite mission carrying an L-band radiometer interferometer. Since its launch, end of 2009, it acquired over 5 years of data that demonstrate the feasibility of the sea surface salinity measurement by L-band radiometry, the capability of the interferometry technique, and it opens new research topics. The LOCEAN team has been involved since 1999 in the definition of direct and inverse models applicable to SMOS. It is one of the ESA Expert Support Laboratory in charge of the definition of the algorithms used for retrieving salinity from SMOS brightness temperatures in the ESA operational chain. The selected candidate will be in charge of the improvement of existing algorithms, dealing in particular with data selection, configuration of the baysian retrieval, radiative transfer model, in close collaboration with researchers and engineers of the laboratory.

The selected candidate will join the LOCEAN IPSO (Interactions et Processus au sein de la couche de Surface Océanique) team involved in the physics of the L-band radiometry, in the satellite salinity validation and in understanding  the processes responsible for the differences observed between satellite and in situ measurements, in particular those linked  to air-sea interaction, vertical stratification and small-scale variability ( and

Work details :

- Developpement of new algorithms for improving the retrieval of the salinity from SMOS mission ; collaboration with the industrial for their implementation in the processor chain

- Relationship with other ESA expert support laboratory and with the company in charge of the evolutions and the maintenance of the processor: participation to weekly teleconference of the SMOS ESA level 2 ocean team and attending the progress meetings (3 per year). Writing of technical papers and participation to scientific papers is possible, depending on the algorithms improvements.

Required Skills:
-          Physics of satellite measurement
-          Data processing and statistics
-          Knowledge of LINUX and C
-          Matlab and/or Python
-          Autonomy and team collaborative working

Welcome Skills:
-          Optimization for huge data processing
-          Interest for environmental science

Level: Research Engineer (PhD thesis or equivalent)

Address : LOCEAN, Université Pierre et Marie Curie, Tour 45-55, 5E, 4, place Jussieu, 75005 PARIS, FRANCE.

Salary : about € 1900 net, commensurable with qualification and experience of the candidate (CNRS salary grid)

Candidates should send a statement of interest, CV and coordinates of 2 referees to  Jacqueline Boutin ( and Nicolas Martin (

SMOS, AMSR-2 and SMAp join forces to track Hurricanes!

Category : L3, L4, Ocean

N Reul and colleagues looked at the signatures of 3 co-evolving 2015 major Hurricanes from 22 Aug to 9 September 2015 in the East and Central tropical Pacific  using SMOS, SMAP and AMSR-2 observations (beyond others)

from Nicolas REUL (IFREMER) from teh SMOS + Storm evolution project (ESA)


Legend: true-colour composite from the MODIS instrument on NASA’s Terra satellite and SMOS surface wind speed amplitude of hurricanes Kilo (left), Ignacio (centre) and Jimena (right) on 29 August 2015. All three were category-4 hurricanes and spanned the central and eastern Pacific basins. The bright bands in the images are sunglint where solar radiation from the Sun has reflected from Earth back to the satellite sensor.

This year sees a strong El Niño event which causes much higher temperatures than normal in the upper layers of the Tropical East Pacific. The available surplus heat favors an increased occurrence of Tropical Cyclones and storms. According to the National Oceanic and Atmospheric Administration (NOAA), this season has been ranked as the fifth most active hurricane season within the Eastern Pacific since 1971.  In a normal season, the average number of Major Hurricanes (Category 3 and plus in the Saffir-Simpson scale) is expected to be 3 whereas this year already 8 Major Hurricanes have occurred.  At the end of August, three Category 4 hurricanes (named Kilo, Ignacio and Jimena) developed in parallel in the vicinity of Hawaii which MODIS and SMOS sensors were well able to capture.

Several types of satellites observations are available to characterize surface winds over the ocean such as active scatterometer radars and passive low-frequency radiometers operating in C and L-band. The advantage of using such radiometers, being an all-weather tool, lies in detecting extreme wind speed (above 33 m/s, i.e., hurricane force) which scatterometers are not able to detect. Three such radiometers, namely, the ESA/SMOS and the recently launched NASA/SMAP L-band and the JAXA/AMSR-2 C-band, are now available to provide such observations.

SMOS surface Tbs and wind speed products along SMOS swaths were determined using the algorithm of  Reul et al., 2012 and updated in Reul et al., 2015. Image Reconstruction based on JRECON (J. Tenerelli, 2011). SMOS Level 1b Tbs are retrieved at antenna level and are further corrected for extra-terrestrial sources contributions, smooth sea surface emission, and atmospheric path effetcs to estimate a storm-surface induced Tb residual. A Quadratic Wind speed GMF is applied to the First Stokes parameter residual  to obtain U, the surface wind speed. Current validation reveals an rms of ~5 m/s up to 50 m/s with respect SFMR flight data or H*Wind analysis at the same spatial resolution than SMOS.

AMSR-2 surface winds are obtained using the  Algorithm developed by Zabolotskikh et al. (2013, 2015a,b) which involves the combined used of highest frequency Chanels (for rain retrieval) and atmosphere corrected 6.925 and 7.3 GHz channels for surface wind inversion.

SMAP: Level 1B data from NSIDC are used, surface first-stokes residual contributions are evaluated  (corrections for atmospheric, cosmic background reflections and smooth ocean surface emission), data with significant galactic reflections are not used  (asc fore beam data are not considered). GMF of Reul et al. 2015 developed for SMOS is applied to retrieved SWS. A systematic offset of -5m/s was added to the retrievals for consistency with ECMWF & NCEP winds for winds <20 m/s)

Thanks to the density of observations available from these 3 missions, the evolution of surface wind speed under tropical storms can now be monitored with an unprecedented spatial and temporal resolution. The example of the 3 co-evolving hurricanes in the East Pacific demonstrate this capability with an ensemble of 121 satellite swath intercepts of the 3 storms obtained by combining the data from the 3 sensors over a period of about 15 days (22 Aug to 7 Sep). The below animation shows the time-series mosaic of surface wind speed measurements under Hurricanes Kilo, Ignacio and Jimena. Data from the three satellite microwave radiometer missions: ESA’s L-band SMOS, NASA’s L-band SMAP and Japan’s C-band AMSR-2 are combined to reveal the track of each hurricane and maximum wind speed measured by each sensor at the ocean surface during the period.

see –> winds from SMOS, AMSR-2 and SMAP


Caption: Contours of the domains showing the maxima of surface winds obtained from the combined multiple observations of SMOS, SMAP and AMSR-2 sensors from 22 Aug to 9 Sep 2015 showing the high wind trails over Hurricanes Kilo and Loke (left), Ignacio (center), Jimena (right).

Comparison of the Maxima of winds from the 3 satellites with Best-Track Maximum winds is shown here below.


Caption: Time series of the Maximum Sustained wind speed as provided by TC’s center (NOAA/HRD and NHC) together with the Maximum wind estimated from SMOS, SMAP and AMSR-2 fro Jimena (top), Ignacio (middle) and Kilo (bottom).

Limitations in the highest wind domains is not due to Tb saturation but to the 30-40 km spatial resolution smoothing effect (Highest-wind generally occur in a narrow region of radius < ~100km around the eyes with very high Wind speed radial gradients).

Key characteristics of hurricanes, such as the radii of wind speeds above a certain threshold (i.e. 34, 50, 64 and 84 knots), can now be captured more often in far more detail. This will greatly improve the representation of initial conditions of Tropical Cyclones in Numerical Weather forecasting systems and hence their prediction.

Interestingly, the higher resolution in space and time of the surface forcing that is gained by the merging of the data from these 3 low MW frequency sensors  will certainly help inferring better understanding of the ocean-atmosphere interactions in TCs:


Caption: Sea Surface Temperature anomalies (in degrees Celcius) reveal cold-water wakes trailing behind hurricanes Kilo, Ignacio, and Jimena highlighting the power of hurricane winds to violently stir the upper ocean and bring cooler waters at depth to the ocean surface.

See as well a recent ESA web-story on the same topic


Reul, N., J. Tenerelli, B. Chapron, D. Vandemark, Y. Quilfen, and Y. Kerr (2012), SMOS satellite L-band radiometer: A new capability for ocean surface remote sensing in hurricanes, J. Geophys. Res., 117, C02006, doi:10.1029/2011JC007474.

Reul, N. et al, A revised L-band radio-brightness sensitivity to extreme winds under Tropical Cyclones: the 5
years SMOS-storm database, submitted to Remote Sensing of Environment, 2015.

E. V. Zabolotskikh, L. M. Mitnik, and B. Chapron, “New approach for severe marine weather study using satellite passive microwave sensing,” Geophys. Res. Lett., vol. 40, no. 13, pp. 3347–3350, 2013.

E. Zabolotskikh, L. Mitnik, N. Reul, and B. Chapron, “New Possibilities for Geophysical Parameter Retrievals Opened by GCOM-W1 AMSR2,” IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens., vol. PP, no. 99, pp. 1–14, 2015a.

E. Zabolotskikh, N. Reul and B. Chapron,  “Geophysical model function for the AMSR2 C- band wind excess emissivity at at high winds“, submitted to GRSL, 2015b.

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