Published October 7, 2016 | Version v1
Dataset Open

Sequence of snow maps produced from Sentinel-2 type of observations (SPOT-5 Take 5) over the Deux Alpes and Alpe d'Huez ski resorts

Creators

  • 1. CNRS

Description

This is a series of snow cover maps between April 11 and September 8, 2015 over a region that covers the Deux Alpes and Alpe d'Huez ski resorts in France. The snow maps were produced from a SPOT-5 Take 5 images using the "Let-it-snow" processor (v1.0, June 2016: http://tully.ups-tlse.fr/grizonnet/let-it-snow).

The SEB folder contains 20 GeoTiff at 10 m résolution in Lambert-93 projection system coded as follows (cf. http://tully.ups-tlse.fr/grizonnet/let-it-snow#products-format):

    0: No-snow
    100: Snow
    205: Cloud including cloud shadow
    254: No data

The "anim_no05jul_opt" animated gif was produced from these data after performing a simple temporal interpolation given by the following rules:

  • If a pixel masked by a cloud was marked as snow in the preceding image and in the following image, then it is reclassified as a snow pixel.
  • If a pixel masked by a cloud was marked as no-snow in the preceding image and in the following image, then it is reclassified as a no-snow pixel.

The July 05 image was removed from the animation due to a cloud/snow confusion. This type of error should be avoided with Sentinel-2 data thanks to an additional "high cloud" test (see http://tully.ups-tlse.fr/grizonnet/let-it-snow/blob/master/doc/tex/ATBD_CES-Neige.pdf).

These data were featured in this blog post : Gascoin, S. "Monitoring the snow cover in ski resorts using Sentinel-2" (19-Sep-2016)  http://www.cesbio.ups-tlse.fr/multitemp/?p=8676

Notes

The SPOT (Take5) experiments consist in using SPOT as a simulator of the image time series that ESA's Sentinel-2 mission will provide. The SPOT4 (Take5) experiment was operated by CNES during the first half of 2013 over 45 sites with the SPOT4 satellite. It received support from ESA, NASA, JRC and CCRS and was proposed by CESBIO. The SPOT5 (Take5) experiment is jointly conducted by CNES and ESA from April to September 2015 over 150 sites with the SPOT5 satellite. SPOT (Take5) Data are processed by THEIA land data center and are distributed with a free and open policy via the joint ESA-CNES webportal spot-take5.org.

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anim_no05jul_opt.gif

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