Glacier fluctuations in the Dry Andes (29º20'S) of Argentina. between 1960 and 2005

ESPIZUA, LYDIA E.; PITTE, PIERRE; FERRI HIDALGO, LIDIA; GARGANTINI, HERNÁN

Santiago, Chile

Conferencia; 4 th Alexander von Humboldt International Conference. The Andes: Challenge for Geosciences; 2008

Facultad de Ciencias Médicas y Matemáticas, Universidad de Chile. European Geoscience Union (EGU).

The rivers in the Andes of Argentina (29º-36ºS) are fed by snow-ice melt from thehigh mountain catchments, so the water is critical for adjacent semiarid lowland communitiesand human activities. There are few studies about glacier fluctuations at theselatitudes in the Andes Cordillera, so this work fills a gap concerning the behaviour ofglaciers in response to climate. The goal of this study is to present the area glacierfluctuations of the Los Amarillos, Guanaco, and Canito glaciers located at 29º20’Slatitude in the Dry Andes of Argentina, based on aerial photos, Landsat TM images,a IKONOS image of 2005, and fieldwork, during the period 1959-2005. The altitudesrange from west to east between 5300-5100 and 3800 m asl. The Los Amarillos, Guanaco,and Canito glaciers are medium-size (1.7, 1.2 and 1.4 km long, respectively).The Los Amarillos glacier presents a slope ranging from 15º to 25º, and a south-eastorientation. The Guanaco glacier is relatively flat with a slope ranging from 5° to 25°,and the Canito glacier is a valley glacier with a slope of 5º-15º in the upper part and15º-25º in its front; both glaciers present an east orientation. The glaciers in the studyarea behave as "reservoir glaciers" with slow movement. They roughly present a similarbehavior from 1959 to 2005. The Los Amarillos glacier present the same area in2005 as it did in 1959, but within this whole period of time the area of this glacierexperienced variations. The Guanaco glacier lost 4% of its area, while the Canitoglacier lost significant amounts of area (33%) during this period of time. The LosAmarillos and Guanaco glaciers increased their areas between 1959 and 1986, whilethe Canito glacier retreated during 1959-1981. These three glaciers showed a maximumincrease in 1981-1986. This increase was followed by an important decrease ofthe areas during 1986-1997, a minor increase in 1997-2000 and a moderate retreat in2000-2005. El Niño warm events at these latitudes are generally associated with highsnow precipitation. The increase of glacier areas in 1981-1986 and 1997-2000, maybe the consequence of the strong warm El Niño events of 1982/1983, 1986/1987 and1997/1998. We present the relation between the long record precipitation time seriesat the El Indio and Santiago-Pudahuel