Theia Snow collection: high-resolution operational snow cover maps from Sentinel-2 and Landsat-8 data

• Published in: Earth system science data Vol. 11; no. 2; pp. 493 - 514
• Main Authors: Gascoin, Simon, Grizonnet, Manuel, Bouchet, Marine, Salgues, Germain, Hagolle, Olivier
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 16.04.2019; Copernicus Publications
• Subjects: Algorithms; Collection; Continental interfaces, environment; Depth measurement; Detection; Earth resources technology satellites; Environmental aspects; Evaluation; High resolution; Image acquisition; Instrument depth measurement; Landsat; Landsat satellites; Mountain regions; Natural history; Remote sensing; Resolution; Satellite observation; Sciences of the Universe; Snow; Snow cover; Snow depth; Visual control
• ISSN: 1866-3516; 1866-3508; 1866-3516
• DOI: 10.5194/essd-11-493-2019

The Theia Snow collection routinely provides high-resolution maps of the snow-covered area from Sentinel-2 and Landsat-8 observations. The collection covers selected areas worldwide, including the main mountain regions in western Europe (e.g. Alps, Pyrenees) and the High Atlas in Morocco. Each product of the Theia Snow collection contains four classes: snow, no snow, cloud and no data. We present the algorithm to generate the snow products and provide an evaluation of the accuracy of Sentinel-2 snow products using in situ snow depth measurements, higher-resolution snow maps and visual control. The results suggest that the snow is accurately detected in the Theia snow collection and that the snow detection is more accurate than the Sen2Cor outputs (ESA level 2 product). An issue that should be addressed in a future release is the occurrence of false snow detection in some large clouds. The snow maps are currently produced and freely distributed on average 5 d after the image acquisition as raster and vector files via the Theia portal (https://doi.org/10.24400/329360/F7Q52MNK).