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OSUG - Terre Univers Environnement

The supraglacial lakes of 79N glacier (Greenland)

Sémianire de P. Hochreuther (FAU, Germany), Jeudi 29 Novembre 2018 à 11h en salle Lliboutry, Bâtiment de Glaciologie

14 novembre 2018, par Fabien Gillet-Chaulet

The supraglacial lakes of 79N glacier (Greenland)

Séminaire de : P. Hochreuther (FAU, Germany)

Abstract :

During polar day, a substantial number of supraglacial lakes appear on the upper tongue of Nioghalvfjerdsbrae (79N glacier), a major outlet glacier of the northeast Greenland ice sheet. These lakes are of interest to glacier modelling (mass balance, ice velocities), as their volume and speed of drainage has been shown to influence ice velocities downstream the lake. Also, they provide an indication of start, intensity and end of the melt season with regards to altitude, thus serving as a proxy for the surface temperature regime on the glacier.
We employ multispectral satellite data (Sentinel-2 and the Landsat series) to detect these lakes and measure their size as a time series, and SAR (TanDEM-X, Sentinel-1)-derived, high-resolution elevation models to estimate the water volume contained in the lakes. Due to the size of data that needs to be processed, this kind of analysis is normally conducted on cloud-based services (Google‘s Earth Engine or Amazon‘s AWS). We set up a local server-based processing and storage system using open source software alone.
The talk will highlight the setup and capabilities of this setup, give insights on the processing chain and present challenges and first results of the analyses.

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