Enneigement des Deux Alpes en octobre 2017

Le 13 octobre on apprenait que le glacier des 2 Alpes n'ouvrira exceptionnellement pas à la Toussaint. Une décision prise en raison de précipitations insuffisantes et des températures élevées cet automne. J'ai fait tourner la chaîne Let-it-snow pour jeter un coup d’œil aux conditions d'enneigement. Hier Theia a mis à disposition l'image Sentinel-2A acquise mardi 17 octobre par temps clair. Voici le résultat :

Carte de l'enneigement le 17/10/2017 dans le domaine de ski d'été des Deux Alpes (en bleu cyan superposée sur le fond de carte OpenStreetMap)

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Yellow skies look grey from above

You must have seen, in the press or social networks, images like these ones, showing yellow skies ( Loup de Bretagne said "Blade Runner skies"). Such a coloured sky was seen in the west of France, then later in England, and further East in the next days.

The Copernicus Atmosphere Monitoring Service, which keeps track of aerosols has also monitored these aerosols and tracked their provenance : is due to the combined presence of dust, ash from forest fires in Spain and Portugal, and humidity brought by the Ophelia cyclone. The IASI sensor on-board METOP satellites has also monitored the gases absorption due those wildfires.

 

So our question is: how such an event is handled by atmospheric correction software ?

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Validation et amélioration des produits Theia Surfaces Enneigées à partir d'images haute résolution

Post préparé par Marine Bouchet pour le blog Kalideos Alpes (version originale)
 
Les séries temporelles d'images optiques des satellites Sentinel-2 permettent un suivi de la surface enneigée à une résolution spatiale de 20 m tous les 5 jours (en l’absence de nuages). Le CNES et le CESBIO développent, depuis 2015, une chaîne Let It Snow (LIS) pour extraire de façon robuste les masques de neige associés, distribués sur la plateforme Theia.
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[Muscate news] temporary slowlyness

Update : MUSCATE is back on track for the real time production, thanks to PEPS return to nominal production, and a better stability of our platform.

Some of you will have probably noticed that Theia production of Sentinel-2 L2A data is quite slow these days, and is not producing all the data it should in real time. The reason is we started to implement a correction to solve the performance issues we had. This correction was tested and qualified during several days, in operational conditions,  but when put in production, turned out to be unstable, due to occasional slowness in CNES cluster which did not happen when the correction was in tests. Moreover, our source of Sentinel2 data, PEPS, was experiencing some difficulties, providing a much reduced number of images.

 

We are waiting for a correction of the correction (the cause has been found and corrected but needs to be tested), The new version should be installed in less than 2.3 days, as Dilbert (dilbert.com) says. And all the team is very sorry for the delays and the inconvenience it is causing.

Venµs' moon

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Well, the audience of our blog is still steady increasing, there is no need to use explicit titles to get more connexions. And although I mainly use space to look down, I do not think the planet has a natural satellite. So why this title ?

The Venµs satellite actually showed us the moon, and not only to provide a nice title in this blog. Our Israeli colleagues from MBT really worked hard to obtain it, as a very good pointing accuracy is needed to image it from a quickly rotating satellite : the moon is far from here !

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Quand Venµs nous montre la lune

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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

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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

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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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