First glacier inventory and recent glacier variations of Isla Grande de Tierra del Fuego and adjacent islands in Southern Chile.

Abstract

The first glacier inventory of the islands south of the Estrecho de Magallanes including Isla Grande de Tierra del Fuego, Isla Santa Inés and Isla Hoste, has been compiled using several ASTER and Landsat ETM+ satellite images acquired between 2001 and 2011, yielding a total area of 3289.5 km2 of glacier cover, distributed among 1681 glaciers. Previous estimations of the total glaciated areas for these islands amounted to only 2500 km2, the difference being attributed to more precise glacier delimitation, and not to glacier advances. Most of the glacier tongues analyzed from recent remotely sensed imagery have been compared to historical data, with a number of glaciers showing retreat in recent decades, especially on the northern side of Cordillera Darwin and at Monte Sarmiento, both located on Isla Grande de Tierra del Fuego. Within the survey area of interest, Glaciar Marinelli showed the maximum change, with a frontal retreat of 15 km between 1913 and 2011. Many other glacier fronts have been stable, with only minor changes since the first historical accounts. Only two glaciers, located at the southern edge of Cordillera Darwin, have shown advances in the last decade; namely Glaciar Garibaldi (+1.1 km between 2001 and 2007), and an unnamed glacier calving into Bahía Pía (+0.6 km between 1991 and 2004). These advancing glaciers seem to be responding to calving oscillations, and not necessarily to a climatic trend in the region, that is currently characterized by atmospheric warming and a reduction in precipitation.