Master's Theses

Date of Award

2015

Document Type

Thesis

Department

Earth and Atmospheric Sciences

First Advisor

Marco Tedesco

Keywords

Remote sensing, cryosphere, hydrology

Abstract

The Greenland ice sheet (GrIS) is one of the largest glacial ice masses on Earth, second only to the Antarctic ice sheet. The surface hydrology of the GrIS plays a crucial role on the surface energy and mass balance budgets of the ice sheet as a whole. Surface water, known as supra-glacial water, is seasonally found in the ablation zone and feeds the en-glacial and sub-glacial hydrological environments of the ice sheet. The spatial distribution of surface streams is poorly understood and their temporal variability is (to our knowledge) unknown. One of the reasons for the lack of knowledge on the temporal variability of such streams is related to the historical unavailability of satellite data that could spatially resolve the presence and associated properties of the streams. In recent years, however, multispectral commercial satellite data in the visible and infra-red bands have been made available to the scientific community. These newly accessible data sets are provided at spatial resolutions on the order of 2 meters, allowing to perform accurate spatial and temporal analysis of surface streams (and small lakes and ponds that cannot be resolved with other sensors such as those on board MODIS or LANDSAT).

In this thesis, I report results concerning the intra- and inter-seasonal variability of surface streams over a selected area on the west Greenland ice sheet. Using multispectral high-resolution imagery from World View - 2 and Quickbird - 2 satellites applied to ArcGIS® software, surface streams were identified through band math algorithms, threshold classifications, and morphological operations. I also provide depth estimations and corresponding volume estimations for the surface water features identified. The supra-glacial hydrology network over the study area was created both with and without lakes for each month. The stream networks created during the melt season (at several different stages of melting) were compared and discussed as well as the networks mapped between consecutive years for proximate dates.

 
 

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