Wet or very wet?

Category : CATDS, L3

Last winter was rather warm and very wet in western Europe while in the US and Canada it was cold or rather very cold!

We looked at the SMOS data collected over Europe as obtained from CATDS and Arnaud extracted the wettest value over ten day periods (here ascending orbits) as shown on the animation below ( to see the animation click on it)

animation-max_ascFig1: maximum soil moisture (around 6 am) over successive ten day periods from January 1 to February 10 2014 as measured by SMOS.

One can see that in Ireland, SW England , W France and SW France soil moisture saturates (value at or above field capacity) indicating sodden soils with heaving pounding. If we look at the product proving minimum value fro the descending orbits we see that even at the driest if was not always completely dry.

animation-min_dscFig2: minimum soil moisture (around 6 pm) over successive ten day periods from January 1 to February 10 2014 as measured by SMOS.

Even in the driest state, note that in some areas the soils are still quite wet.

These picture show how we can track saturated to flooded areas with SMOS. Also note the impact of RFI in some areas , giving rather dry soils when / where not expected.

Drought over Western Europe

Category : L2

Western Europe is experiencing a noticeable deficit of water. England has already considered the situation as serious (http://www.bbc.co.uk/news/uk-england-17102615), see the following map of drought risk.


SMOS allows us to get the soil moisture content of the top layer of the surface, but this drought is well observed. It concerns not only the UK but also Spain as can be seen in the following figure. It presents the soil moisture as derived from SMOS in February 2010, 2011 and 2012 (average values), for ascending overpasses (corresponding to measurements in the morning at ~ 6am, solar local time). Note that February 2010 was still the beginning of the mission and  the commissioning phase, which explains some lack in the retrievals.


Low soil moisture levels are seen in yellow (less than 0.10 m3 of water / m3 of soil, i.e. less than 10%  in average in February), and it is more obvious when compared to the soil moisture at the same period last year. The next figure shows the differences between the months of February 2012 and February 2011 over Europe (as 2012 – 2011), for the ascending overpasses . The red color (i.e. negative values) stands for 2012 being drier than February 2011, whereas the blue is the opposite, i.e. February 2011 being drier than 2012. The Following animation presents also a zoom over Spain, which presents a significant decrease of water content.



SMOS dielectric constant product and its uses during the last cold spell in Europe

Category : CATDS, L2, L4

SMOS delivers one « strange » or rather unusual product which is an estimate of the surface dielectric constant (see ATBD!). A example of it’s potential use is shown below with the fields of dielectric constant estimated over Europe for two periods corresponding to the arrival of a cold front over Western Europe. The first picture corresponds to the period going from January 28 to 31 2012. The cold spell is arriving but not quite there yet. The second picture shows the dielectric constant for the period going from February 2nd to 5th, 2012. As one might remember, it was quiet cold and soil was often frozen while snow was widely spread over Europe (and quite dry as it was cold). The dielectric constant consequently dropped significantly. This can been seen on the pictures with the dielectric constant dropping from values equivalent to wet soils (typically 15) to values for very dry or frozen soils (1 to 3) which gives this more blueish shade.


January 28 to 31:  western Europe is grayish white hence high dielectric constant values …


February 2-5, 2012. Western Europe is under snow or frozen, … much lower values of the dielectric constant.

Al Bitar and al, CESBIO

8 orbites et 1/2

Category : Commissioning phase

Les choses avancent plutot bien ici (dès qu’un truc marche on boit du champagne, alors ça encourage…), j’ai extrait tous les accès madagascar acquis jusqu’ici (2 en tout) et je vais les traiter dès demain. J’ai aussi lancé le SML2PP sur la première orbite (Ouest US) juste pour voir, 4h et 3Go de mémoire sur mon petit pc…
C’est trop cool, on voit très bien que Washington et Oregon sont plus humides que Mojave et que la San Joaquin Valley pompe toute l’eau de la Sacramento river.

Première image de l'humidité de surface

Première image de l'humidité de surface

J’ai aussi transféré les 8 premières 1/2 orbites sur http://sie.ups-tlse.fr/fc_smos/l1c, j’ai également mis les adf pour le L2 dans http://sie.ups-tlse.fr/fc_smos/adf_l2.
Attention en regardant les l1c : certaines zones en europe et asie mineure souffrent gravement de RFI (supposées) qui bavent sur tout le champ de vue à cause de l’étalonnage sol. Pas de panique, les choses vont s’arranger très prochainement (enfin, j’espère :-) )

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