Mapping Greenland Supraglacial Melt Lakes and the Role of Local- and Synoptic- scale Climates in Their Variations
Open Access
- Author:
- Amador, Nathan S
- Graduate Program:
- Geography
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 29, 2014
- Committee Members:
- Andrew Mark Carleton, Dissertation Advisor/Co-Advisor
Richard B Alley, Committee Chair/Co-Chair
Robert George Crane, Committee Member
Dr Rudy Slingerland, Committee Member
Byron Richard Parizek, Special Member - Keywords:
- Greenland
supraglacial melt lake
climate
atmospheric circulation - Abstract:
- My doctoral research utilizes remote sensing and GIS techniques to evaluate the influence of climate on the surface hydrology of the Greenland Ice Sheet. Specifically, I assess changes in supraglacial melt lake spatial and temporal patterns in the ablation zone (or melt zone) along the ice sheet margin around Jakobshavn Isbræ. Supraglacial melt lakes play a significant role in ice sheet hydrology and mass balance as they have the propensity to catastrophically drain. Such episodic drainage events inject surface meltwater to the ice sheet–bedrock interface, lubricating the bed, and provide a mechanism for a dynamic response in ice flow. The contribution of Greenland’s outlet glaciers to sea level rise has doubled over the last two decades due to this increased calving. I introduce a novel tool, FoveaPro (a plug-in to Adobe Photoshop), for mapping supraglacial melt lakes in the ablation zone from satellite imagery. FoveaPro allows the user to semi-automate supraglacial lake mapping, making lake identification more time efficient, and to generate more-precise spatial statistics (such as melt lake area and shape) on these lakes than current manual methods. I identify atmospheric circulation patterns coincident with anomalously high and low melt periods in the context of a 13-year climatology. I utilize depth-reflectance algorithms that have been previously developed for this region, to calculate melt lake volume. To ensure accuracy of the melt lake volume calculations, the results were compared with estimates from a degree-day model that utilizes data from a nearby weather station in the ablation zone, and with satellite-derived digital elevation models (DEMs). A more thorough understanding of the amount of surface meltwater stored in supraglacial lakes, and its atmospheric drivers, better constrains its impacts on ice sheet hydrology and consequent ice sheet contribution to global sea level rise.