High Altitude Meteorology and Snow Geochemistry,
Bolivian Andes

ICE, News Bulletin of the International Glaciological Society
(to appear soon)

Douglas R. Hardy, Mathias Vuille, & Raymond S. Bradley

    Dept. of Geosciences, University of Massachusetts, USA

At the summits of two Andean mountains in Bolivia, automated weather stations (AWS) and snowpack analysis are being used to improve the calibration of geochemical variations within tropical ice cores. One station was installed in October 1996 on the ice-capped volcano Sajama (6542 m, 18°06'S, 68°53'W), where a team led by L.G. Thompson (Ohio State University) recovered two ice cores to bedrock from the summit in June and July of 1997. The other station is located near the summit of Nevado Illimani in the Cordillera Real (6,265 m; 16°39'S and 67°47'W), where another drilling campaign is anticipated within the next few years. These satellite-linked AWSs are providing hourly measurements of snow accumulation and ablation, along with snow temperature and a variety of meteorological variables.

The objective of these efforts is to better understand the atmospheric sources of geochemical variability in the snow. The analysis of station data is closely tied to the results of annual snowpack studies carried out in the vicinity of the automatic weather stations. Individual stratigraphic layers in the snow pits are delineated and sampled in detail (for oxygen isotope ratios, microparticles and major ions), enabling the episodes of snowfall to be characterized in terms of precipitation geochemistry. Ultimately, the analysis of the prevailing meteorological conditions associated with precipitation events, as measured at the stations, combined with regional airflow derived from satellite imagery, and reconstructed from NCEP global analyses (National Centers for Environmental Protection of NOAA), will enable different airflow patterns to be associated with variations in the geochemistry of the snow. This will then provide valuable insight into the interpretation of down-core geochemical variations within ice cores from the Tropics.

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Climate System Research Center | Department of Geosciences | University of Massachusetts

Document maintained by Doug Hardy (dhardy@geo.umass.edu)
Last updated: 1 October 1998
http://www.geo.umass.edu/climate/bolivia/ice98.html