Climate Variability And Change In High Elevation Regions Past Present Future

Climate Variability and Change in High Elevation Regions: Past, Present & Future

Glaciers in the Andes are particularly important natural archives of present and past climatic and environmental changes, in significant part because of the N-S trend of this topographic barrier and its influence on the atmospheric circulation of the southern hemisphere. Strong gradients in the seasonality and amount of precipitation exist between the equator and 30° S. Large differences in amount east and west of the Andean divide also occur, as well as a change from tropical summer precipitation (additionally modified by the seasonal shift of the circulation belts) to winter precipitation in the west wind belt (e. g. , Yuille, 1999; Garraud and Aceituno, 2001). The so-called 'dry axis' lies between the tropical and extra tropical precipitation regimes (Figure 1). The high mountain desert within this axis responds most sensitively to the smallest changes in effective moisture. An important hydro-meteorological feature on a seasonal to inter-annual time-scale is the occurrence of EN SO events, which strongly control the mass balance of glaciers in this area (e. g. , Wagnon et ai. , 2001; Francou et ai. , in press). The precipitation pattern is an important factor for the interpretation of climatic and environmental records extracted from ice cores, because much of this information is related to conditions at the actual time of precipitation, and this is especially so for stable isotope records. Several ice cores have recently been drilled to bedrock in this area. From Huascanin (Thompson et ai. , 1995), Sajama (Thompson et ai.

Climate Variability and Change in High Elevation Regions

Climate Variability and Extremes during the Past 100 years

This volume provides an up to date overview of climate variability during the 20th century in the context of natural and anthropogenic variability. It compiles a number of contributions to a workshop held in Gwatt, Switzerland, in July 2006 dealing with different aspects of climate change, variability, and extremes during the past 100 years. The individual contributions cover a broad range of topics. The volume fills a gap in this exciting field of research.