Snow cover in the High Mountain Asia on 13 May 1960

TIROS-1 weather satellite was launched by NASA on 01 April 1960. It took the first weather satellite picture on 02 April 1960 [1], and also the real first weather satellite picture on 01 April 1960 [2].
 
On 02 April 1960 it took what I believe is the first publicly available satellite picture of the snow cover in the Alps (picture 1 below). On 13 May 1960 it captured a stunning view of the snow cover over the High Mountain Asia, including the Himalayas, Hindu Kush, Pamir and Karakoram ranges. These pictures are shown in the TIROS-1 final report [3].


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❄ Powder alarm on Theia / Avalanche de produits neige sur Theia ❄


Yesterday Theia shifted into high gear and released 1300 snow products!. These products correspond to 13 Sentinel-2 tiles covering the Western Alps (France/Italy/Switzerland), the Pyrenees (France/Spain) and the Hight Atlas (Morocco).


Hier Theia est passé à la vitesse supérieure et a mis à disposition 1300 produits neige ! Ces produits correpondent aux 13 tuiles Sentinel-2 qui couvrent les Alpes Occidentales (France/Italie/Suisse), les Pyrénées (France/Espagne) et le Haut-Atlas (Maroc).

This was made possible thanks to the great work of Dominique Clesse, Joëlle Donadieu, Céline L'Helguen, Arnaud Selle and Simon Baillarin at CNES. Merci à eux !

Theia distribue les premiers produits neige

Nous sommes heureux d'annoncer que Theia a mis en ligne 93 produits neige faits à partir de Sentinel-2. Ces produits correspondent à 6 tuiles qui couvrent une partie des Alpes, des Pyrénées et de l'Atlas pour une période comprise entre juillet et novembre 2016. La production opérationnelle devrait débuter cet automne (c'est-à-dire au fil de l'eau), et couvrira une surface plus grande. Nous essaierons aussi d'améliorer les produits grâce aux retours des utilisateurs.

Série temporelle de produits neige pour la tuile 30TYN (Pyrénées)

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Theia releases first batch of snow products

We are pleased to announce that Theia has put online 93 Sentinel-2 snow products, corresponding to 6 tiles in the Alps, Pyrenees, and Atlas mountains between July 2016 to November 2016. 300 more products should be available next week. The operational production should start in autumn 2017 (i.e. near real time), and will cover a larger area. We will also strive to improve the products based on the users feedbacks!

Time series of available products for tile 30TYN (Pyrenees)

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3D views of Aru Co avalanches from Pléiades stereo imagery

A Pléiades stereo pair has been acquired on 2016-Oct-01 just a few days after the second glacier collapse in the Aru mountains. The panchromatic band has 0.5 m resolution, which allowed us to generate a post-event digital elevation model of the area. From this digital elevation model and the Pléiades 2 m multispectral imagery, Etienne Berthier generated these stunning 3D views of the aftermath...

Preliminary estimates of the volume detached from the glaciers are 66 Mm3 (first, north one) 83 Mm3 (second, southern one).

Monitoring the snow cover in ski resorts using Sentinel-2

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We are preparing the distribution of maps of the snow cover extent made from the Sentinel-2 data for Theia. If the method used to detect the snow is based on well-proven concepts, spatial and temporal resolution of the snow maps will however quite unprecedented. Until now, maps of the snow cover extent were usually produced from MODIS observations at 500 m resolution, which is adapted to hydro-climatic studies to rather regional scales. Landsat data were actually little exploited by snow scientists because of their low repeatability. The deployment of Sentinel-2 mission (global coverage at 20 m resolution every 5 days) opens new perspectives for monitoring snow cover.
 
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Sentinel-2A (and Landsat-8) capture a giant ice avalanche in Tibet

After reading my previous post about the Rutog ice avalanche, my distinguished colleagues Antoine R. and Olivier H. challenged me to look for a pre-event image to better highlight the avalanche area. The closest clear-sky image that I could find is a Landsat-8 image that was acquired on June 24 (23 days before the slide).

 

Sequence of two Landsat-8 and Sentinel-2A images. Both images are level 1 product displayed as natural color composites. Click to enlarge.

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