Tous nos voeux pour 2018 !


Que cette nouvelle année vous apporte joie et bonheur, et pas seulement dans l'utilisation de séries temporelles !


Sans aucune originalité, ce début d'année est l'occasion de faire un petit bilan de l'année 2017. Voici, dans notre domaine, quelques uns des faits que je retiendrai :

  • la consécration du programme Copernicus, et des satellites Sentinel. Plus de 110 000 personnes se sont inscrites pour accéder aux données depuis 2015 !  A mon avis, ce succès est dû à la combinaison de plusieurs facteurs : les données sont gratuites et faciles d’accès, les observations sont répétitives, régulières et fréquentes sur le monde entier, et les données sont de grande qualité. Un grand bravo à l'ESA et à l'UE, sans oublier la contribution du CNES pour la qualité des images de Sentinel-2 et l'étalonnage de Sentinel-3. Continue reading

Our blog's audience in 2018


A sixth year begins for the "Séries temporelles" blog, and as usual, it is an opportunity to review its audience, and to get a little self-satisfaction.

The blog is always receiving more visits. even if the annual growth rate is much lower than the previous years, but still 20%... French visitors constitute only 35% of visits. The United States rank second, followed by Morocco, which is probably an effect of CESBIO's long presence in Marrakesh. Then come France neighbouring countries.


2013 2014 2015 2016 2017
Number of visits 13985 22928 34723 47773 57692
Number of viewed pages 30922 46940 66947 89555 105846

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Fréquentation du blog en 2017


Une sixième année commence pour le blog Séries Temporelles, et comme d'habitude, c'est l'occasion de revenir sur sa fréquentation, et de faire un peu d'autosatisfaction.


Le blog reçoit toujours plus de visites. même si la croissance devient inférieure à 20%..en un an. Les visiteurs Français ne constituent plus que 35% des visites. Les Etats-Unis viennent en second, suivis par le Maroc, ce qui est probablement un effet de la longue implantation du CESBIO à Marrakech.

2013 2014 2015 2016 2017
Nombre de visites 13985 22928 34723 47773 57692
Nombre de pages lues 30922 46940 66947 89555 105846

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Data upload on MUSCATE distribution server is slow

It seems that the upload of data to MUSCATE distribution server is quite slow these days. This results in a delay in the provision of data. As CNES is closed between Christmas and the new year, we will have to wait a little to have it repaired. We are sorry for that inconvenience. But you can use this opportunity to rest and spend time with your families without having to process our scenes :) . We wish you all a happy Christmas week.

Il semble que la mise à jour du serveur de distribution de MUSCATE très lente depuis quelques jours,c e qui cause d'importants retards de distribution. Comme le CNES est fermé entre Noel et le jour de l'an, nous devrons attendre pour réparer ce problème. Nous vous prions e nous en excuser. Mais vous pouvez en profiter pour passer des vacances en famille sans avoir à traiter nos données ;) . Passez tous de bonnes fêtes !

MAJA Sentinel-2 L2A processor downloaded more than 200 times

Since spring 2017, we have made the MAJA cloud screening and atmospheric correction processor available for commercial use. A bit later, end of June, the Sen2agri software package, which includes MAJA older version (named MACCS) , was also released to the public. We did not expect a large success, as these two packages are quite heavy ones, do not work on laptops, and require a specific linux system powerful computers (Red Hat or CentOS).

Anyway, the MAJA processor has had quite a large success, even if, I guess, it is far from the success of Sen2cor, which is much easier to install and use, even if the performances are not the same. The figures below correspond nearly to one download per day.


Number of downloads of MAJA (stand alone version) 93
Number of downloads of MACCS (Sen2Agri version)i 116


To celebrate this fact, we just published a brand new MAJA detailed description.

A brand new MAJA ATBD

I have always wanted to provide an Algorithm Theoretical Basis Document related to MAJA, but never had time, because I always had more urgent things to do. Some papers had been published, allowing MAJA users to get a good idea or the methods we use, but the published articles did not cover all the features of MAJA.


But this time, due to a contractual engagement with ESA, it was the urgent thing to do. So, at last, after a few weeks of hard work, here it is.


If you have already read the papers from our team, you will recognize some text published quite a long time ago, but we updated all the text and added some parts which had not been explained yet in journal publications, and of course the new parts recently added to MAJA. This ATBD is now in line with version 2.0 of MAJA.

[MUSCATE] A little error on Sentinel-2B L2A products processed before December 1st.

When we started making tests of the L2A production at MUSCATE with Sentinel-2B data, we considered using a small correction of Sentinel-2B to correct for a eventual bias between the reflectances of each satellite. Such differences were observed by colleagues form CNES, and were comprised between 0 and 2.5%.  Finally, we decided not to implement this in the operational line, because the figures we had were based on a small duration of acquisitions and were possibly not accurate enough.


Band name Coefficient
B1 1.002
B2 0.995
B3 1.000
B4 1.008
B5 1.009
B6 1.017
B7 1.014
B8 1.024
B8A 1.012
B9 1.000
B10 1.000
B11 1.004
B12 0.986


Due to a human error, it turns out that the parameter file that we used for these tests made its way to the operational line. MAJA parameters are kept under a GIT version manager, which should reduce the probablility of such errors, but that parameter file is a parameter of MUSCATE, not MAJA, which was not managed yet. And as you know, according to Mr Murphy, when something can turn wrong, it turns wrong. the test calibration adjustment made its way to the production line.


For the Sentinel-2B L2A products produced until the 30th of November, the L1C TOA reflectance  values were divided by the coefficients provided in the table above. On the first of December, this error was corrected. As the differences are quite small, we have not removed the Sentinel-2B products produced before December 1st, but we are going to reproduce them and replace them by the correct values during the coming weeks.


We are sorry for hat error, which will make us improve our verification procedure.



Building a global cropland mask, is not an easy task

Criticizing is easy, and doing is hard, especially when trying to create a global map of croplands. Some collegues from CESBIO have worked on that subject within the Sen2Agri project, and obtained good resuts, but only at the local or country scale. Finding a method that works everywhere must clearly be much harder.

These days, I have received a lot of emails, tweets and posts about a new cropland global product at 30 m resolution, edited by USGS. I have no doubt it was a serious work from a serious team, done with appropriate terrain data and methods, validation, and of course a tremendous data processing.



But there it is, I checked it over a lot of places that I know very well, and it seems to me that the cropland mask, at least in South West France, is clearly overestimated. Is it the same in tour region ? Here are some examples :

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Le bulletin Theia est sorti !

De la part de Sophie Ayoubi, chargée de la communication de Theia

Le 8ème numéro du bulletin du pôle de données et de services surfaces continentales Theia vient de paraître.

A découvrir dans ce numéro :

  • Actualités
  • Nouveaux produits
  • Services et outils
  • Applications et thématiques
  • Développement instrumental
  • Accompagnement utilisateur

Téléchargez le bulletin de Theia en version impression (3.6 Mo) ou version allégée (932 Ko) ou feuilletez-le en ligne dans l'espace Calaméo de Theia.

Retrouvez l’ensemble des numéros dans la rubrique bulletins.

MUSCATE news : 50000 L2A products from Sentinel-2A and 2B

Since it became operationnal in December last year, MUSCATE has produced 50 000 level 2A products from Sentinel-2A. Let's recall what has been processed so far :
  • For 550 tiles, we have processed all Sentinel-2A data acquired since December 2015.
  • For 100 tiles, mainly in South America, and in Italy, we have processed all Sentinel-2A data from December 2016. We are currently catching up the backlog for Italy, and later on, for South American sites.
  • For all these 650 tiles, we are producing all Sentinel-2 data (Sentinel-2A and Sentinel-2B) in near real time. I think THEIA is the only place where you can download Sentinel-2B L2A data so far. ESA has not started that production yet (nah, nah, nah :) )
  • For all these 650 tiles, we have processed all Sentinel-2B data since beginning of October 2017. We will soon catch-up with the Sentinel-2B data acquired from July 2017.



See full screen

Map of the 650 tiles currently processed in near real time (in red). The blue tiles will be added beginning of next year.


All these products are available from


Let's recall that MUSCATE uses the MAJA L2A processor, which uses multi-temporal criteria to perform a high quality cloud detection and atmospheric correction. Despite the recent installation of version 2.4, MUSCATE still regularly suffers from instability as soon as CNES High Performance Computer is overloaded. The problem does not lie in MAJA, but in the information exchanges between all the components of MUSCATE which need to respect an accurate timing (sorry, I am not able to explain better).


The exploitation team just installed a new version of MUSCATE (v 2.4.16.p2 (!)), which is expected to increase stability. But that's the theory, let's see if it works in the coming days and if we are able to increase our production rate.