Greenland CCI+ - Supraglacial Lakes

Region: Greenland

Duration: 2 yr (January 2023 - January 2025)

Collaboration partner: Technical University of Denmark (DTU), ASIAQ Greenland Survey

Introduction

In the last ~25 years, Greenland has lost 4000Gt of ice, making it the second largest contributor to ice loss globally (Slater et al., 2021). Over half of this ice loss is attributed to a negative surface mass balance, to which surface melt plays a large role (Box et al., 2022). Surface meltwater on Greenland typically manifests itself as supraglacial lakes (SGL) and streams on the ice surface. The timing of onset, extent, duration, and drainage of supraglacial lakes are unpredictable and their effects are significant. Increased freshwater supply not only impacts ecological communities, ocean chemistry, and the global ocean circulation system, but it also acts to lubricate the bed over which the glaciers increase their flow speed. Increased discharge from outlet glaciers contribute to sea level rise. 

Owing to the increased temporal and spatial coverage of recent satellites, researchers now have access to imagery every few days over Greenland. For replacing manual/semi-manual mapping of SGL, automated machine learning solutions are being explored in order to quickly and efficiently make use of the satellite data. Deep learning may also increase our understanding of lake bathymetry and act to provide data where observations lack. The overall aim of the Greenland Ice Sheets Climate Change Initiative (GIS CCI) is to produce data products relating to five Essential Climate Variables (ECVs) which describe and monitor the Greenland Ice Sheet. 

The contribution by S&T includes utilising state-of-the-art deep learning models to map both SGL extent using optical imagery from Sentinel-2 and SGL depth using laser altimetry from NASA’s IceSat-2 satellite. The proposed outcome is a data product containing SGL extent and depth for two focused regions on Greenland; 79 and Zachariae glaciers in the north-east and Sermeq, Kujalleq and Jakobshavn glaciers in the south-west.

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Link to project website: https://climate.esa.int/en/projects/ice-sheets-greenland/