Quand Venµs nous montre la lune


Non, non, la fréquentation de ce blog n'est pas en baisse au point qu'il nous faille attirer une nouvelle clientèle pour compenser une perte de revenus financiers issus de la publicité. (La fréquentation augmente régulièrement d'ailleurs, mais les revenus financiers sont nuls...)

Le satellite Venµs nous a vraiment montré la lune, et ce n'est pas seulement pour proposer une belle image et un titre accrocheur sur le blog du CESBIO. Nos collègues israéliens de MBT se sont d'ailleurs donné beaucoup de peine pour l'obtenir, car il faut une très bonne précision de pointage pour l'observer : la lune est loin !

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Soil moisture maps at a high resolution over Occitania region


Translated from Theia website.

The Theia forges just released a new product based on Sentinel-1 and 2 data. Le "High resolution soil moisture" Scientific Expertise Center, driven by Nicolas Baghdadi, from Tetis lab in Montpellier and Mehrez Zribi from CESBIO, distributes Soil Moisture maps from the French Occitania region at 20 m resolution, produced every sixth day from September 2016 to May 2017.

Soil Moisture maps for 2 Sentinel-1 images from the 19th and 26th of January 2017, over a part of Occitania région. On the 19th of January, the soil is dry with a moisture between 5 and 15 vol.%. After some precipitations, on the 26th of January 2017, moisture increases between 25 and 35 vol.%.

Des cartes d’humidité du sol à haute résolution en Occitanie


Article rédigé à partir des articles du site Theia.

Les forges de Theia viennent de mettre à disposition un nouveau produit basé sur les données Sentinel 1 et 2. Le CES “Humidité du sol à très haute résolution spatiale”, animé par Nicolas Baghdadi, du laboratoire Tetis à Montpellier et Mehrez Zribi du CESBIO, propose des cartes d’humidité du sol sur la région Occitanie à l’échelle sub-parcellaire élaborées tous les 6 jours de septembre 2016 à mai 2017.

Cartes d’humidité des sols pour deux images Sentinel-1 du 19 et du 26 janvier 2017 sur une petite zone de la région Occitanie. La carte du 19 janvier 2017 montre que le sol est sec avec des valeurs d’humidité entre 5 et 15 vol.%. La carte du 26 janvier 2017, après des précipitations, montre des humidités entre 25 et 35 vol.%.

[MUSCATE news] 40 000 Sentinel-2 L2A products !

Our MUSCATE ground segment just passed a new milestone, with 40 000 L2A products processed with MAJA ! Last week was a bit difficult, with a new repetition of the Friday Night Bug (on Saturday morning this time), followed by a "NFS" issue on CNES computing center that blocked production during two days. We are sorry for those of you waiting for the data in near real time. The production has resumed last Friday. These days, our production includes the near real time production and the processing of data acquired in 2016 over Spain, Italy, Switzerland and Netherlands. Some parts are already available, Burgos in Spain for instance, the others should come soon.



The version 2.4 of MUSCATE is nearly ready, but a final bug, noticed during the qualification tests remains to be corrected. As soon as it is installed and checked, this version will bring several improvements :

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MAJA presentation at the Recent Advances in Quantitative Remote Sensing symposium, fifth edition

I just came back from Valencia, where I attended the fifth edition of the  Recent Advances in Quantitative Remote Sensing Symposium. It is one of my favourites, thanks to an amazing team of organizers led by Jose Sobrino. It is a unique symposium, because it has only one session  where you can even see opticians listen to radarists, or passive microwaves experts share ideas with active microwave experts ! Every three years, it is a way to gather quickly a good sense of the advances in each domain of remote sensing, over lands mainly. Next RAQRS will happen in 2020 in Valencia, and no doubt I'll be there, and not only for the delicious coffee breaks or for the giant paella.


Of course, my talk, available here or visible below, was about Sentinel-2 L2A products, including cloud detection and atmospheric correction. This time, I focused on product validation and provided a lot of validation results obtained by our little team at CNES and CESBIO, with special thanks to Camille Desjardins (CNES) and Bastien Rouquié (CESBIO) and Magdalena Main-Knorn (DLR). I also provided a comparison of MAJA and Sen2cor for various criteria that all show the benefits of using multi-temporal information, as done in MAJA. Despite all that, and although these results were perfectly known by ESA, ESA decided to stick with Sen2cor in their production, supposed to be global next year. The slides explain how this decision was made.


Anyway, as you probably know, you can access MAJA products from Theia, or you may also download MAJA's executable (if you have a powerful linux computer).





Aftermath of Mathew hurricane over Haiti in 2016

Following Simon's publication on Saint Barthelemy island after Hurricane Irma, one of our twitter friends, @Pierre_Markuse, posted a comparison of the South Western part of Haiti, before and after Mathew huricane ravaged it last year, on the 4th of October 2016. As you can see, the whole lands turn brown just after the hurricane. I am really not an expert, so I just can imagine it is caused by the wind cutting branches and trunks and by water run-off taking the lower vegetation away.  I read that 40% or the  forest and 20% of the shrub has been erased. Moreover, the wind and water must have left mud and dust on the remaining leaves, contributing to the brown color.


However, what is amazing is that by end of November, vegetation comes back ! My guess is that mud and dust disappear, shrubs and trees start to grow new leaves and the low vegetation grows back  But experts are welcome to explain how it happens exactly, there is a comment section !


I have an additional special own interest in displaying this information :  it is a hard test for how our multi-temporal methods included in MAJA to detect clouds, shadows and aerosols can manage such a case. Continue reading

[MUSCATE] 1141 L2A products in a day !

Yesterday, MUSCATE facility at CNES produced 1141 Sentinel-2  L2A products in a day, while the previous record was 762. A few glitches had reduced the production on the previous days, and yesterday allowed us to catch up the back log. At the same time we have started producing data acquired in 2016 for several zones outside Europe and Africa. The total number of L2A products in MUSCATE now amounts to 33071. Congrats and thanks to the development and exploitation teams !

Hier, le centre de traitement MUSCATE au CNES a traité 1141 produits de niveau 2A de Sentinel-2, alors que le record précédent était 762. Quelques petits soucis avaient retardé la production ces derniers jours, et c'est hier que nous avons rattrapé le retard, et en même temps lancé la production des données acquises en 2016 sur un grand nombre de  zones hors Europe et Afrique. Le nombre total de produits de nievau 2A atteint maintenant 33871. Félicitations et un grand merci aux équipes de développement et d'exploitation !


Les premières images de Venµs


Les vrais produits du nouveau satellite Venµs seront des séries temporelles d'images de la terre (pas la planète Venus), acquises tous les deux jours sur plus de 100 sites. Mais pour obtenir ces séries temporelles, il faut que Venµs soit sur son orbite nominale, qu'il rejoindra courant septembre. Mais nous sommes déjà très heureux de partager avec vous les premières images prises par le satellite, pour vous montrer que la caméra, la mémoire et la transmission marchent comme prévu ! C'est déjà beaucoup, et après les habituels debuggages, vérifications, caractérisations et étalonnages, nous recevrons bientôt nos séries temporelles !

L'une des premières images acquises par Venµs, au dessus de Phoenix (Arizona, USA), sur laquelle on peut observer de nombreuses parcelles agricoles irriguées.



Mais je ne devrais pas trop en dire, alors que le CNES a publié un communiqué de presse officiel , pour lequel chaque mot a été pesé, discuté et approuvé.

Un grand merci à tous ceux qui, en France et en Israël, ont contribué à cette rapide et heureuse publication !

Venµs first images


The real products from the new Venµs satellite, will be time series of high resolution images of the Earth (not Venus planet) acquired every second day on more than 100 sites. But to get these time series, Venµs needs to be on its nominal orbit, which will be reached beginning of September. Anyway, we are happy to share the first images taken from the satellite, just to let you know that Venµs camera, memory and downlink work as expected ! It is already a lot, and after the usual debugging, verification, calibration and assessment, we will soon get our time series.

One of Venµs first images acquired above Phoenix (Arizona, USA), with a lot of irrigated fields.



But I'd better not tell too much, while I can just provide the official press communication from CNES, on which each word was weighted, discussed and approved !

Many thanks to all my French and Israeli colleagues who contributed to this quick and successful achievement.

Sentinel-2 ground segment restarted, but a backlog remains to be processed

From Scihub news :

Referring to the news of 11 August , users are informed that the contingency issue occurred at Matera has been solved and nominal Sentinel-2A/B production was restarted yesterday 16 August in the early afternoon.
An inventory of the missing production is being consolidated and all impacted S2A/B L1C products will be recovered in the coming weeks, together with the ongoing recovery of missing products between 1st and 8th August as reported in the news of 09 August .