“Observations on small Andean glaciers located between 29º-32° South latitude”

LEIVA, J.C; CABRERA, G. A.; NOVELLO, V. L.; CASTELLER, A.

Santiago de Chile

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

European Geosciences Union

Observations on small Andean glaciers located between 29º and 32º south latitude J. C. Leiva (1,2) , G. A. Cabrera (1), V. L. Novello (1)  and A. Casteller (1) (1) Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Conicet, Mendoza, Argentina (2) Facultad de Ciencias Agrarias- Universidad Nacional de Cuyo, Mendoza, Argentina jcleiva@lab.cricyt.edu.ar Water availability is one of the main impacts that mankind will have to face in the near future. Its economical consequences for the irrigated oases of Mendoza and San Juan provinces, situated in the western part of Argentina (Leiva et al. 1986, 1989, 1999, 2007) could be severe if the water resource management is not improved and appropriate adaptation and mitigation strategies are not adopted to cope with water shortage. In spite of their small size, many glaciers in the Andes of Mendoza and San Juan provinces are a very important source of water during drought periods, when the annual snowfall in the Central Andes of Argentina and Chile is scarce. It is also known that they rapidly react to climate fluctuations therefore they will rapidly show us the regional impacts of Global Change. This work shows the results of monitoring a number of small glaciers (area < 1.3 106 m2) located in the Andes range between 4500 and 5500 m. It includes observations on the Los Amarillos glacier and its neighbour the Amarillo glacier (29º18’S, 70º00’W), the Brown glaciers, called Superior, Inferior and Norte (29º 59’S, 69ª38’W), the Agua Negra glacier (30º10’S, 69º50’W) and the Piloto Este glacier (32º37’S, 70º09’W). The glaciological work conducted on each of these glaciers focused on different aspects. On the Piloto Este glacier (between 4185 and 4740 m asl) mass balance studies started in 1979; in the summer of 1982 its maximum ice depth was obtained by seismic profiling. In 1965 Colqui initiated the survey of the front fluctuations of the Agua Negra glacier. GPR and geolectrical surveys of this glacier were performed during the last five years of the 20th century. The mass balance studies and GPR surveys in the Brown glaciers begun in 2003 but only the winter mass balance was obtained. The 2007–2008 annual mass balances of these glaciers were the first to be calculated. GPR surveys and the 2007–2008 annual mass balances studies were also conducted in the Amarillo and Los Amarillos glaciers. The analysis of all the obtained data and the comparison of previous terrestrial and aerial photos and satellite images show that these small glaciers have experienced a recession. The Piloto Este mass balance series shows that this glacier is in views of disappearing in the near future. Moreover, there is no evidence to suggest that the other mentioned small glaciers would behave differently. Previous works show that, during drought periods, the glacier contribution reaches up to 60 to 70 % of total runoff on the Central Andes of Argentina and Chile (Bown et al., 2008; Leiva, 1982, 2002, 2007; Milana et al. 1997; Peña et al 2007). For that reason, the observed glacier recession will have strong impacts on the water availability of the region.  ID-Nr: AVH4-A00092 Corresponding author: Fax: 54 261 524201 / Phone: 54 261 5244205, E-mail address: jcleiva@lab.cricyt.edu.ar