March 29, 2018
West margin of Cook Ice Cap in 2001 and 2018 Landsat images. Red arrows indicate terminus margin in 2001 in both images. Nunataks A-D and Nunatak Lacroix (L) are also shown.
On the west side of the Cook Ice Cap on Kerguelen Island a series of outlet glaciers have retreated and several nunataks have either expanded or are no longer surrounded by ice. The glacier include Pasteur, Pierre Curie, Larmarck and Descartes from north to south. Here we examine the changes from 2001-2018 along using Landsat imagery. This is a very cloudy region and no other images allowed a clear view, except a Sentinel image also from 2018. Retreat of glacier in the region was examined by Berthier et al (2009) and is exemplified by the retreat of Ampere Glacier. Verfaillie et al (2016)examined the surface mass balance using MODIS data, field data, and models. They identified that accelerating glacier wastage on Kerguelen Island is due to reduced net accumulation and resulting rise in the transient snowline since the 1970s, when a significant warming began.
On the west side of Cook Ice Cap in 2001 there is one significant Nunatak in the midst of the ice cap Nunatak Lacroix (L). Nunatak A and D do not exist. Nunatak C is encircled by ice and Nunatak B is nearly surrounded. Pasteur Glacier reaches tidewater across a broad front in 2001. By 2018 Nunatak D has emerged 1.2 km inland from the margin. Nunatak A has also emerged 4.0 from the ice margin. Nunatak C is now a ridge separated from the ice cap. Lacroix Nunatak is much expanded. Pasteur Glacier is narrower has retreated 600 m and does not reach tidewater, but terminates on a proglacial delta. Pierre Curie Glacier 1.2 km and is now just 2 km from the ice cap margin. Lamarck Glacier that terminated in a proglacial lake has now retreated from that lake, a retrated 1100 m. Descartes Glacier has retreated 1000 m with a narrow arm of the lake extending northward. A new proglacial lake has also formed down glacier of Nunatak D. The retreat of the western margin of the Cook Ice Cap supports the mass balance losses determined by Verfaillie et al (2016). The east side of the Cook Ice Cap is also retreating forming a new lake district.
West margin of Cook Ice Cap in 2018 Sentinel image. Red arrows indicate terminus margin in 2001 in both images. Nunataks A-D and Nunatak Lacroix (L) are also shown. Retreat of outlet glaciers at the five arrows is 900 m.