Recent Fluctuations and Damming of Glaciar Perito Moreno, Patagonia, Observed by Means of ERS and Envisat Imagery

Frontal positions and a lake damming event are investigated for Glaciar Perito Moreno, one of the main calving outlet glaciers of the Southern Patagonia Icefield, using ERS SAR data available since 1992 and Envisat ASAR data since 2002. The satellite data, in synergy with field measurements, confirm the stability of the glacier, showing only minor frontal fluctuations and indicating an approximately balanced mass budget since many years. This is in contrast to the majority of Patagonian glaciers which have been subject to considerable retreat during the last 50 years. Climatic and orographic factors of relevance for differences in glacier response are discussed, based on a comparison of Moreno glacier with the adjoining Ameghino glacier which is retreating. ASAR data are also used to study the recent damming event of Moreno glacier that started in mid-October 2003 after a minor frontal advance, and ended with a collapse of the ice dam in March 2004. Due to the rise of the water level by more than 8 metres, 22 km of pasture land were flooded in the southern arm of Lago Argentino. The motion behaviour and frontal observations suggest that the damming was triggered by minor fluctuations of mass fluxes of a glacier close to equilibrium and does not represent a surge event.

[1]  Yu Zhang,et al.  Sensitivity of mass balance of five Swiss glaciers to temperature changes assessed by tuning a degree-day model , 2000, Journal of Glaciology.

[2]  Temporal changes of Glaciar Mayo and Laguna Escondida, southern Patagonia, detected by remote sensing data , 1999 .

[3]  Charles F. Raymond,et al.  How do glaciers surge? A review , 1987 .

[4]  D. Sugden,et al.  The Patagonian Icefields: A Glaciological Review , 1993 .

[5]  G. Casassa,et al.  Meteorological and Climatological Aspects of the Southern Patagonia Icefield , 2002 .

[6]  Erik R. Venteris,et al.  Rapid tidewater glacier retreat: a comparison between Columbia Glacier, Alaska and Patagonian calving glaciers , 1999 .

[7]  P. Skvarca,et al.  Recent Glacier Variations in the Southern Patagonia Icefield, South America , 1997 .

[8]  Eric Rignot,et al.  Contribution of the Patagonia Icefields of South America to Sea Level Rise , 2003, Science.

[9]  G. Casassa,et al.  Volume changes on Pio XI glacier, Patagonia: 1975-1995 , 1999 .

[10]  J. Oerlemans,et al.  Holocene glacier variability: three case studies using an intermediate-complexity climate model , 2003 .

[11]  Helmut Rott,et al.  Mass fluxes and dynamics of Moreno Glacier, Southern Patagonia Icefield , 1998 .

[12]  P. Skvarca,et al.  Recent variations of calving glaciers in Patagonia, South America, revealed by ground surveys, satellite-data analyses and numerical experiments , 1995, Annals of Glaciology.

[13]  Masamu Aniya,et al.  Current Knowledge of the Southern Patagonia Icefield , 2002 .