520 years of glacier mass balance proxy records in NW Patagonia reconstructed from instrumental climate data and tree-ring width series.

MASIOKAS, M.H.; LUCKMAN, B.H.; VILLALBA, R.; LARA A.; URRUTIA, R.

Corvallis, Oregon, USA

Conferencia; PAGES First Young Scientist’s Meeting and Third Open Science Meeting; 2009

PAGES

Very few, short mass balance measurements are available for glaciers in the Patagonian Andes. We have therefore developed proxy glacier mass balance data using instrumental climate and tree-ring records in an attempt to improve understanding of the impacts of inter-annual and inter-decadal climate variations on glacier behavior. Initially, we developed a 1912-2002 climate-based proxy series using homogenized, regionally-averaged temperature and precipitation data that mimicked regional glacier mass balance relationships in NW Patagonia. Subsequently we extended this record back to 1481 using an extensive, multi-species network of tree-ring width chronologies from sites on both sides of the north Patagonian Andes. In both series extended periods of “positive” proxy values are interpreted as periods during which climatic conditions were relatively more favorable for glacier growth and vice versa. This approach can provide useful baseline information to put the 20th-century regional climate and glacier changes in a longer term context. Comparison with the history of glacier fluctuations in NW Patagonia during the last 500 years shows some promising results. However, this approach should only be considered preliminary because of the simplicity of the climate-based indices used, the absence of direct glacier mass balance records for validation, and the lack of detailed information on regional glacier variations in this region. More sophisticated approaches may be developed once more detailed glacier-climate linkages are established and a larger network of glacier mass balance and tree-ring records become available.