SMOS Drought Monitor – CATDS L4

Category : CATDS, L3, L4

A new drought index has been developed at CESBIO by including SMOS surface soil moisture to a double bucket model. The index is computed operationally. You can access it on this (here) dedicated page or by clicking on « Drought Monitor » in the SMOS blog header tab


This new product is part of the level 4 SMOS products. These are end-level products, obtained by the combination of the SMOS data to physical models (hydrological, statistical with/without data assimilation…) or by using remote sensing data from other sensors (Disaggregation, data fusion, synergism …).

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You can also access the SMOS Africa Root zone soil moisture Index (SARI) in the Princeton Africa Drought Monitor (here) (look at 02 April 2012, this will be operational soon)

SMOS L4 team

(version Française)

Un nouvel indice de sécheresse issu de l’intégration des données SMOS dans un modèle hydrologique double réservoirs a été développé au CESBIO. Il est produit de façon operationnelle. Vous pouvez y accéder via le site dédié du produit en appuyant (içi)

Cet indice de sécheresse est un produit CATDS de niveau 4 SMOS. Les produits de niveau 4 issus de la mission SMOS sont des produits de niveau supérieur obtenus en combinant les produits SMOS de niveau 1,2 ou 3 à des modèles physiques ou en utilisant d’autres capteurs.

Vous pouvez aussi accéder à l’indice SARI (SMOS African Root zone soil moisture Index) dans le système  de suivi de la sécheresse  en Afrique mis en place à l’Université de Princeton (içi) (voir le 02/04/2012, cet indice sera mis en mode operationel dans les jours à venir)


SMOS L4 team

Drought over Western Europe

Category : L2

Western Europe is experiencing a noticeable deficit of water. England has already considered the situation as serious (, 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

Drought in Europe

Category : CATDS, L2, L3

Using SMOS soil moisture monthly data François Cabot produced the following animation.

It is made by simply comparing monthly soil moisture in 2010 and 2011…

We can clearly see the drought starting in Western Europe (UK, France,…) in March-April to slowly but surely move twowards teh East (Germany, Poland, …) as we get to November while Spain and Southern France get some rain…

Just click on the image to see the animation


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