Jorge Arigony Neto

Variations of glacier frontal positions on the northern Antarctic Peninsula

Abstract Changes in the ice fronts on the Antarctic Peninsula north of 70˚ S are currently being investigated through a comprehensive analysis of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) data as part of the international research initiative ‘Global land Ice Measurements from Space’ (GLIMS). Regional case studies are presented that cover a variety of glacial systems distributed over the northern Antarctic Peninsula and provide data on glacier front variations during the period 1986–2002. The results confirm a general trend of regional glacier front recession, but a range of different glacier variations are observed throughout the study area. Areas of predominant retreat are located in the northeastern and southwestern sectors, while stationary ice fronts characterize glacial behaviour on the northwestern coast of the peninsula. In addition, a significant increase in glacier recession is identified on James Ross Island, where retreat rates doubled during the period 1988–2001 compared to the previous investigation period, 1975–88. These observations are interpreted as being direct consequences of the rapidly changing climate in the region, which differentially affects the local accumulation and ablation patterns of the glacial systems.

Perspectivas para o gerenciamento ambiental da baía do almirantado, ilha Rei George, Antártica

Este trabalho descreve o uso inicial de um sistema de informacoes geograficas (SIG) para auxiliar no gerenciamento da AreaAntartica Especialmente Gerenciada (AAEG) da baia do Almirantado, exemplificado mediante os resultados preliminares obtidos. Seguindorecomendacoes do Protocolo ao Tratado Antartico sobre Protecao ao Meio Ambiente (Protocolo de Madrid), foi utilizada informacao geoespacialintegrada em SIG para demarcar os limites da AAEG. A area foi recalculada em 362 km2 (antes fora estimada em 370 km2). Combase na sobreposicao de informacoes na peninsula Keller (no norte da baia do Almirantado), foi representado espacialmente o local onde,seguindo as definicoes do Protocolo de Madrid, havia sido detectado impacto ambiental menor ou transitorio no trabalho de campo. Apossibilidade de utilizacao do SIG recem-implantado no gerenciamento ambiental da baia do Almirantado cresce a medida que surge anecessidade de escolha de areas aptas a ocupacao humana, bem como da avaliacao do impacto ambiental causado pelas atividades na area.