June 5, 2011

Ampere Glacier Retreat Kerguelen Island

Posted by Mauri Pelto

Kerguelen Island sits alone at the edge of the furious fifties in the southern Indian Ocean. he island features numerous glaciers, the largest being the Cook Ice Cap at 400 square kilometers. A comparison of aerial images from 1963 and 2001 by Berthier et al (2009) indicated the ice cap had lost 21 % of its area in the 38 year period.Kerguelen-Island-topo-Map T In this paper they focused particular attention on the Ampere Glacier draining the southeast side of the ice cap. Berthier et al (2009) noted a retreat from 1963 and 2006 of 2800 meters of the main glacier termini in Ampere Lake. The lake did not exist in 1963. The map below is from the paper indicating the terminus position. A second focus of their work was on the Lapparent Nunatak due north of the main terminus and close to the east terminus. A nunatak is a ridge or mountain surrounded by a glacier, really an island in a sea of ice. The nunatak expanded from 1963-2001, in the middle image below from Berthier et al (2009), but it was still surrounded by ice. The bottom image is from Google Earth in 2003. Given our current climate I wondered what might have changed in the last few years. Landsat images from 2001, 2009, 2011 and 2013 indicate the retreat of the main terminus at the orange arrow and the secondary terminus at the red arrow. The east terminus has retreated 1500 meters since 2003 leading to the expansion of a new substantial lake. The main terminus has retreated additionally 800 meters from 2001-2013. Here the terminus has pulled back from the tip of the peninsula on the west side of the terminus, which the orange arrow crosses in each image. This glacier is experiencing the same climatic warming that has led to the retreat of other glaciers in this circum-Antarctic latitude belt, Arago Glacier further south on Kerguelen, nearby Aggasiz Glacier Stephenson Glacier on Heard Island and Neumayer Glacier on South Georgia. In this ever changing world, it is melting that is changing our maps.ampere glacier 2001
2001 Landsat image
2009 Landsat image

ampere 2011
2011 Landsat image

ampere 2013
2013 Landsat image.