April 23, 2011

Penny Ice Cap Retreat, Baffin Island

Posted by Mauri Pelto

The Penny Ice Cap is extends north from the Pangnirtung Pass regiion of Baffin Island


To capture the majesty of the region, you have to turn to the artwork of Cory Trepanier, seen below is his Great Glacier study, not to the science data. The ice cap has been shrinking as evidenced by the retreat of a number of outlet glaciers. This post focuses on two of these glaciers. The first is Turner Glacier which flows 11 km downvalley from the ice cap ending in the Pangnirtung Valley. In 1961Turner Glacier reached to the summit lake in Pangnirtung Pass. In 1953 the glacier front was also much wider as seen in an Arctic Institute of North America Photograph. In the images below Turner Glacier enters from the left center of the image. By 2004 (top image) the glacier had receded 280 meters from the lake shore and 600 meters from the moraine it was in contact with in 1953. By 2009 the retreat was 570 meters from the lake shore and 900 meters from the moraine, bottom image. The 2009 image is an August 2009 Landsat Image.

In particular retreat after 2000 has been more rapid. Coronation Glacier is the largest outlet glacier of the Penny Ice Cap, it extends 35 km from the edge of the ice cap terminating in Coronation Fjord. Syvitski (1992) noted that Coronation glacier has been retreated at an average rate of 12 meters per year from 1890-1988 Coronation Glacier. The focus at Coronation Glacier (C) is the imagery from 2004 and 2009 both indicating a lack of snow cover on some of the small glaciers adjacent to this glacier. Glaciers A and B are nearly snow free in both summers, and this is still in August. The small glacier labelled D is snow free in 2009. . In this five year interval The Coronation Glacier has retreated 200 m. Note the change in the glacier terminus position with respect to the stream entering the north side of the fjord at the terminus. The limited snow cover on Baffin Island mirrors that of most of the Canadian Arctic in recent years with high melt rates leading to mass balance losses and sea level rise as published this week by Gardner and others (2011).