MONITORING GLACIER VARIATIONS IN THE SOUTHERN PATAGONIA ICEFIELD
UTILIZING IMAGES LANDSAT 7 ETM+
Luis Felipe Ferreira de Mendonga®
!CEPSRM, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
1felipem@msn.com
COMMISSION VIII, WG VIII/10 - Cryosphere
KEYWORDS: Cryosphere, Glaciology, Glacier Variation, Landsat 7, Database
ABSTRACT:
The monitoring of the variation in glacier areas is increasingly important with the apparent trend of
global warming. One of the majorice sheetson the planet, the main glaciers of
Southern Patagonia Icefield were mapped using a set of images obtained in 1973, 1976, 1979, 1986,
2005 and 2009 by the ETM + sensor onboard the Landsat 7 satellite. The images were calibrated to
planetary radiance and reflectance, where the supervised classification of each image sought to
obtain the physical limit of the snow with each glacier. Maps were generated with the terminal
position of the glacier tongue for the dates analyzed. The results were compared with previous
publications and showed peculiar behavior of each glacier, especially from the images of 1986,
where there was a pattern of decrease in surface area of glaciers. And the temporal analysis will
show the behavior of glaciers to the present day.
1. INTRODUCTION different and several authors have studied its
glaciers since 1950.
The Patagonian Ice Field is the second largest
glacier in the Southern Hemisphere. Located at
the southern tip of South America, moves on
the border between Argentine and Chilean
territories. Composed of two large regions: the
Northern Patagonia Icefield (NPI) and the
Southern Patagonia Icefield (SPI), with areas of
approximately 4.200 km? and 13.000km?
respectively. In the light of an apparent trend of
global warming in recent years, it is important
the monitoring of the variations of several
glaciers on a global scale. With emphasis on
temperate glaciers, which tend to respond to Figure 1. Study area — Mosaic of two digital photographs
of Southern Patagonia Icefield.
climate changes in a relatively short period of
time. Currently, most studies are conducted for
specific glaciers, for example as the Moreno
glacier (ANIYA, 1992(1); ROTT, 1998;
STUEFER, 1999), Upsala (ANIYA, 1992 (1);
SKVARCA, 1995), Bruggen (IWATA, 1983;
With the passing of years the studies about
global warming, and the behavior of glacier
areas, have been intensified all over the world.
With the Patagonian ice field wasn’t no
