Recent acceleration of ice loss in the Northern Patagonia Icefield based on an updated decennial evolution P. López1,2 and G. Casassa1 1Centro de Estudios Científicos (CECS), Arturo Prat 514, Valdivia, Chile 2Laboratoire Hydrosciences, UMR5569, CNRS – IRD, Universities 1 & 2, 34095 Montpellier Cedex 5, France
Received: 26 Oct 2011 – Accepted: 09 Nov 2011 – Published: 03 Dec 2011
Abstract. Ice elevation changes of the Northern Patagonia Icefield (NPI) were analyzed
by comparing three Digital Elevation Models (DEM) corresponding to 1975
(constructed based on topographic maps), the SRTM DEM of 2000 yr and a
SPOT 5 DEM of 2005. In addition, the glacier length fluctuations and the
surface area evolution between 2001 and 2011 of 25 glaciers of the NPI were
studied: the information extracted from the Landsat ETM+ satellite image of
11 March 2001 was compared to the measurements performed based on the
Landsat ETM+ satellite image of 19 February 2011. From a global point of
view, the majority of the studied glaciers thinned, retreated and lost
surface between 2001 and 2011, only few glaciers (Leones, Nef, Pared Sur and
Soler) located on the eastern side of the NPI have been stable. Glaciers
located on the western side of the NPI suffered a stronger wasting compared
to the glaciers located on the eastern side.
Overall, over the ablation areas of the NPI (below 1150 m a.s.l.) a more
rapid thinning of 2.6 m yr−1 occurred between 2000 and 2005 yr compared to
the period 1975–2000, in which a mean thinning of 1.7 m yr−1 was measured for
the same zones of the NPI. For the whole period (1975–2005) the most
important thinning of the ablation areas has been estimated for HPN-1
Glacier (4.4 m yr−1) followed by Benito (3.4 m yr−1), Fraenkel (2.4 m yr−1),
Gualas (2.1 m yr−1) and Acodado glaciers, all of them located on the western
side of the NPI.
Between 2001 and 2011, a noteworthy retreat of 1.9 km was experienced by
Gualas Glacier and by Reichert Glacier with 1.6 km, both located on the
north-western side of the NPI. On the south-western side of the NPI, during
the same decennia, Steffen Glacier experienced a remarkable retreat of 1.6 km
as well. During the 2001–2011 period, Steffen Glacier more than doubled
its rate of retreat (compared to the 1979–2001 period) and experienced the
disintegration of its main front as well as a lateral tongue that retreated
3.1 km. The most significant retreat observed on the eastern side was
experienced by Colonia Glacier (1 km).
Area loss was also relevant during the period 2001–2011. Overall, the
icefield experienced a reduction of 50.6 km2 which represents a 1.3 %
relative to the surface area calculated for 2001 yr. The most remarkable
surface reduction was observed for HPN-1 Glacier that lost 3.2 % of its
surface estimated in 2001, followed by Steffen Glacier (2.8 %).
We suggest that the glacier shrinking observed in the NPI is controlled
firstly by atmospheric warming, as it has been reported in this area.
Nevertheless, updated climatic studies are needed in order to confirm this
suggestion. If the detected past climate trends persist, in the future,
glaciers of the NPI will continuous or even increase their rate of shrinking
generating important consequences for this region like the production of
Glacier Lake Outburst Flood events or the decrease of the melt-water runoff
in the long-term future.
Citation: López, P. and Casassa, G.: Recent acceleration of ice loss in the Northern Patagonia Icefield based on an updated decennial evolution, The Cryosphere Discuss., 5, 3323-3381, doi:10.5194/tcd-5-3323-2011, 2011.