My (big) mistake wrt LEWIS

Category : Cal/Val, Data, ground measurements

I would like to complement a statement I made on several posts which is inaccurate!

I said on several occasions that LEWIS had been designed by F Lemaitre from ONERA when he actually designed the receiver etc but not the horn which was designed by CNES (M Dejus). I may even add that the design of the horn inspired the design of EMIRAD horn probably and, moreover, was used directly for CAROLS and MARMOTTE2.

This being corrected, I am glad to add hat LEWIS, in the Alps, is still running strong!

MARK your Calendars !!

Category : CATDS, Cal/Val, Data, L1, L2, L3, L4, Model, Ocean, Satellite, Training

The 2nd SMOS SCIENCE CONFERENCE (25-29 May 2015) and the SMOS TRAINING COURSE (18-22 May 2015) will take place at ESA-ESAC, near Madrid (Spain).

For further information on both events please see

The deadline for submission of abstracts for the SMOS science conference and applications for the SMOS training course is 16 January 2015.

The 2nd SMOS Science Conference will be jointly organised by ESA, CNES and SMOS-MODE.

By 2015, the SMOS mission will have been in orbit for more than five years, providing a continuous stream of high quality data products. Being a water cycle mission, SMOS observations have been used by rather distinct science communities addressing oceanography, land surface hydrology, and meteorology over a wide range of applications. The focus of this conference will deviate from previous events in that the emphasis will be on applications of SMOS data, including operational services, the development of novel data products, the synergistic use of SMOS data with other data sources and the potential of SMOS data for the generation of long-term data sets. The workshop will also cover common themes such as the quality of the Level 1 data products and calibration and validation activities.

The 2nd SMOS Science Conference will be preceded by a SMOS Training Course on 18-22 May 2015, organised by CESBIO and held as well at the ESA-ESAC premises near Madrid. The course will provide an opportunity to learn how to work with level 1 (brightness temperature) and level 2 (soil moisture and ocean salinity) data provided by the SMOS mission. The deadline for applications is 16 January. To submit your applications please go to –> Training Course and use the link on the bottom of the page.

LEWIS on the move: Part 2

Category : Cal/Val, Data, ground measurements

As posted last June our good old faithful LEWIS (Lemaitre et al, 2004) after spending 9 years in SMOSREX near Toulouse underwent maintenance and updating and was moved to Saint Hilaire du Touvet  near Grenoble by François Lemaître and Arnaud Mialon.

The road trip was arduous as LEWIS is not small to say the least while it is « a long and winding road » to the top…




Once on site (in spite of the snow melt mud) the whole set up with LEWIS and its supporting frame was hoisted and put in place…

And then the connecting testing etc was performed by François while LEWIS was overhanging the valley below….gauging the situation. Enventually Arnaud and François got everything ship shape and the fine tuning started.

The instrument can scan the valley below (Azimuth and elevation and will make continuous measurements on selected spots. Calibration is done as was done during SMOS REX with a few automatic sky measurements performed using a reflective plate (and manual one aiming directly at the sky). In Valley ground measurements are performed on the selected sites and our COSMOS probe will move from Toulouse next spring.


We are collaborating with Thierry Pellarin from LTHE Grenoble for this campaign.

First results are encouraging. There are some small RFI but François is devising a scheme to make sure we identify them. The connection between the instruments has also hiccups but here as well Arnaud and François identified the cause and it should be corrected soon.

Our contraption is located close to some para-gliders and we must say they were a bit mystified at the beginning… but the pictures they take from up there are quite nice (this picture was taken by Christian).

Below some first measurements made by LEWIS in St Hilaire du Touvet on the left hand side the temporal plots acquired over a forest and lake mix footprint (some RFI visible). In green the Infra red temperatures and in Red and blue respectively the V and H pol. On the right hand side the view seen by the radiometer when doing these measurements.

lewis_TB_champs_foret_lac_zoom08 nov 14   12h sur Centre2

To finish this story Arnaud made a scan of the whole area and you will see the brightness temperatures (V pol) of the valley as seen from LEWIS  either from above (RHS) or with the perspective (LHS) not the industrial area (coldish due to metallic roofs) the warmish urbanised areas.


And now the next step is to do some science with this set up… so keep posted!

The funding was partly from SMOS CESBIO but also from CNES TOSCA programme. The Mairie was of very big help and made all what was possible to enable this experiment. The local companies were of great help too and did a mint job … A very big thank to all of them.


Lemaître, F., J.-C. Poussière, Y. H. Kerr , M. Dejus, R. Durbe, P. de Rosnay and J.-C. Calvet (2004). « Design and test of the ground based l band radiometer for estimating water in soils (lewis). » IEEE Geoscience and Remote Sensing 42(8): 1666-1676.

LEWIS is on the move! Part One

Category : Cal/Val, Data, ground measurements

Back in 2002 we had a high quality ground based radiometer built by ONERA (Jean Claude Poussière and François Lemaître) with CNES funding (TOSCA) (see Lemaitre et al, IEEE). This radiometer was installed in a fallow field south of Toulouse together with classical equipment to monitor the various meteorological and soil variables (see de Rosnay et al, 2006). In 2011 a COSMOS probe was added to the set up  (for more info see here).


LEWIS during tests before implementation (2002)

From January 2003 to last year the set up worked almost continuously (there was one big maintenance though) providing a wealth of measurements in all possible conditions (wet years, dry years, snow, freezing soils, storms etc….) with L band dual polarised data acquired at angles from 20 to 60° on both bare soil and fallow land.  Moreover, on several occasion we did specific campaigns  for instance to alter roughness over a large range of values etc). This gave way to a number of publications and helped improving LMEB and the L2 retrieval algorithm sub models…


Lewis in operation at the SMOS REX site near Toulouse

The data set is available for other research purposes. Just ask if you need part of the data set ( During this whole period, with only one maintenance stop, the instrument worked extremely well with a remarkable stability and accuracy. It even went through a bush fire unscathed!

But after 9 years in operation we decided it might be useful to go to other places and, in collaboration with ONERA (F Lemaître), INRA ISPA (Jean Pierre Wigneron as always since start !) and LTHE (Thierry Pellarin) we looked for, and found, an adequate location close to …


The idea was to find a site where we could have more occurrences of snow and cold weather but mainly a set up offering a capacity to have well characterized mixed footprints.

Finally Arnaud and Thierry found a place satisfying all criteria close to Grenoble and we started the move … The first step was to refurbish LEWIS and replace the filters (to reduce RFI risks) this was promptly done in 2012. More complicated was setting up the site as it is located in altitude and we had to have a platform overhanging the valley built, we had to have energy brought to the site and to develop the mechanisms to point the antenna.

radiomètre lewis

Testing the controllers in a warmer (!??) and safer place than on top of the cliff!

This was done during this last winter but we then had to wait for the of the winter and snow melt before we coudl transport and finally implement our equipment on site …

This will be described in part two together with the first plots

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