Our first L2A images obtained with Sentinel-2B (and Sentinel-2A)

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The Sentinel-2B satellite was launched in March 2017, and joined his twin brother Sentinel-2A, which was orbiting since June 2015. Both satellites are now succeeding each other above our heads every 5 days. Sentinel-2 system mission is to monitor the evolution of the landscape and especially vegetation, with an observation every fifth day.

 

Very quickly, ESA managed to obtain Sentinel-2B observations over Europe very steadily, which is quite an achievement : congratulations to ESA ! CNES was greatly involved in assessing the image quality and in calibrating the sensor and has its own L1C processor (level 1C provides images registered to maps, expressed in reflectance at the top of Atmosphere).

 

By merging the time series take by Sentinel-2B and Sentinel 2A above a few sites, we managed to get dense time series of images over a few sites. To monitor a landscape, it is necessary to detect the clouds and their shadows, and to correct the variations of atmosphere transparency. This is the job of MAJA processor, which is developed jointly by CNES, CESBIO and DLR. Camille Desjardins, from CNES made it run over one of the sites..

 

So, here is the time series we obtained over a zone in Provence, France. The detected clouds are circled in green. If one ignores the clouds, which are well detected, the animation shows the slow evolution of the landscape as spring arrives. It is not possible to see a difference between the images provided by Sentinel-2B, and Sentinel-2A, which is in fact the aim of the Sentinel-2 mission. All the users will soon have access to high quality time series, with frequent observations, every five days in the absence of clouds !

 

The Muscate production center, at CNES, already distributes level 2A products  provided by MAJA software above selected regions, from Sentinel-2A data. As soon as Sentinel-2B is declared operational, its images will also be integrated in the processing.

Les sites Venµs / Venµs sites

Here are the sites that will be observed by the long awaited French-Israeli satellite Venµs. Venµs will be launched this summer, and three months after launch, all the sites will be observed each second day from a constant viewing angle with 10m resolution and 12 spectral bands. Combined with Sentinel-2 and Landsat 8, a daily repeatitivity will almost be obtained.

Voici les sites qui seront observés par le satellite Franco-Israelien Venµs, attendu depuis si longtemps. Venµs sera lancé cet été, et 3 mois après le lancement, tous ces sites seront observés tous les deux jours, à 10 m de résolution et avec 12 bandes spectrales. En combinant les données de Venµs avec celles de Landsat 8 et Sentinel-2, nous approcherons même d'une revisite quotidienne.

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Erratum to "Landslides in Kyrgyzstan captured by Sentinel-2"

In this post "Landslides in Kyrgyzstan captured by Sentinel-2" I showed two landslides that I identified as the Kurbu and Ayu landslides, both featured in the AGU landslide blog. However, as pointed out by Isakbek Torgoev, the Kurbu-Tash landslide is located about 5 km farther south than the one I found on the Sentinel-2 image of Apr 29. The actual Kurbu-Tash was not visible in this image due to cloud cover, but today I found a more recent image (May 19), where the Kurbu-Tash landslide is evident.. and it's even more massive! From this image I estimate that the runout distance of the Kurbu-Tash is about 7 km and not 3.5 km.
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OTB news : version 6.0 and User days : 7-9 June, Toulouse

OTB version 6_0 is out ! It includes many improvements (including an unsupervised machine learning framework), and adopts a new, more permissive licence : Apache v2.0

My colleagues in charge of the Orfeo Toolbox Development (OTB) are organizing the annual user

meeting in Toulouse town center : June 7-9 2017. Here is the program :

  • Day 1: Plenary session (general presentations from the OTB Team and the users)
  • Day 2: Technical session (tutorial, work groups)
  • Day 3: Hackfest (adopt an OTB developer, code a amazing feature, fix a bug)

If interested, please have a look to the the webpage and register.

MUSCATE news : release of Madagascar Sentinel-2 L2A data

After a good period with very little production incidents, our Muscate facility has had a tough period, which almost halted the production for one week. Until last week, the Muscate ground segment was running on CNES older cluster, and was just using the new cluster's bay of disks to store the input and output data. The access to the bay was made through the network and slowed the processing. Last week, we moved Muscate to the new cluster, and also moved physically one of the computers we are using : this brought us a few surprises that took more time than expected.

 

Muscate is now running on the new cluster : it has its own reserved computing nodes, and a dedicated facility for the scheduler. The result is that the processing of a L2A product with MAJA now only takes 23 minutes on average, while it used to be 50 minutes before. All the teams who did that migration, handling the development of Muscate, its exploitation, or the cluster facility, deserve acknowledgement !

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Sentinel-2 adds colors to the 2017 super bloom in California

Texas had the super bowl in 2017 but California got the super bloom!

 

After its worst drought in 1,200 years, California is now experiencing one its wettest year. The Sierra Nevada snowpack is currently one of the biggest ever recorded. In February, severe winter rainfalls caused the evacuation of many California residents under the threat of the Oroville Dam failure.

 

Now, this unusual level of rainfall triggered the blossoming of flowers that were in a dormant state. The Washington Post collected some photographs and noted that it was so so massive that you can see it from space (images were provided by Planet, a California-based remote sensing company).

 

How does it look like in Sentinel-2 imagery? Below is the comparison between two Sentinel-2 images acquired in spring 2016 vs. spring 2017 near the Carrizo Plain National Monument (see by yourself in the sentinel-playground).

 


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10000 L2A products available at Theia for Sentinel-2

The number of L2A products from Sentinel-2 available at Theia, just passed above 10 000 ! Data from France, Belgium, North of Spain, Morocco, Tunisia, Senegal, the Burkina-Mali transect, or La Reunion Island are now processed in real time : our requirement is 60 hours, after the data is available in Copernicus hub. Next site to be added is Madagascar.

 

Le compteur de produits de niveau 2A de Sentinel-2, disponibles à Theia, vient de passer la barre des 10 000 produits. Les données acquises par Sentinel-2 sur la France, la Belgique, le Nord de l'Espagne, la Tunisie, le Sénégal, le transect Burkina Mali, et l'île de la Réunion sont maintenant traitées en temps quasi réel : notre spécification est de les mettre à disposition en moins de 60 heures après leur apparition sur les serveurs du hub de Copernicus. Le prochain site couvrira une bonne partie de Madagascar.