Changes in the Harding Icefield and the Grewingk-Yalik Glacier Complex, Kenai Fjords National Park (KEFJ)

Hall, Dorothy; Giffen, Bruce; Chien, Janet

Glacier changes in the mountains of the Kenai Peninsula, Alaska, have been analyzed in the Harding Icefield and the Grewingk-Yalik Glacier Complex in Kenai Fjords National Park (KEFJ). Glaciers that originate in the park, and flow outside of the park are also included. The Harding Icefield spawns more than 38 glaciers of which some are tidewater and others are land-based, or wholly or partially terminate in lakes. We used Landsat Multispectral Scanner (MSS), Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) scenes to outline glacier areas and terminus positions on four scenes. Glacier outlines were done using vector segments to produce shape files for the Geographic Information System (GIS) analysis. Results show that most of the glaciers in KEFJ have receded since 1973, some dramatically. These results are generally consistent with results from extensive work done in the 1990s on the Harding Icefield by previous researchers. For this project, we derived GIS shape files,and from those we can calculate glacier area and terminus changes from 1973 to 2002, and estimate the 1986 equilibrium-line altitude (ELA) for the large glaciers. We also did a classification of the 1986 and 2002 Landsat scenes to measure the areal extent of the two ice masses, and found that there was a reduction of 3.62%, or approximately 78 km2 from 1986 to 2002, with most of the changes occurring in the Harding Icefield. Some issues that complicate the analysis include: fresh snow cover and spatial resolution differences between images.

Changes in the Harding Icefield and the Grewingk-Yalik Glacier Complex, Kenai Fjords National Park (KEFJ)

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