Showing papers on "Accumulation zone published in 1988"

Trace-acid ion content of shallow snow and ice cores from mountain sites in western Canada

Abstract: An historical record of the deposition of common acids is contained in snow and ice cores taken from suitable sites in the accumulation zone of certain glaciers. Spatial and time-series data sets for trace-mineral acids have been obtained from snow-pit samples and ice cores from a number of mountain sites in Alberta, British Columbia, and the Northwest and Yukon Territories. In Alberta, it is possible to use temperate firn sites above 3460 m, although elution occurs during certain summers as indicated by isotopic and ionic data. This would also apply to sites of a similar latitude (52°±2°N) in British Columbia. In the Yukon Territory (≥60.5°N) reliable time series for the acid anions may be obtained from sites at altitudes above 3000 m. Elution provides a natural control for demonstrating that field sampling and subsequent analytical procedures do not introduce significant contamination. The Yukon data are compared with the net annual accumulation rate and with altitude. Recent data from the 5340 m Mt Logan site do not indicate any significant increase in natural background levels of snow acidity. Lightning, which is responsible for numerous forest fires in all provinces, is a possible natural source of nitric acid. Spring-summer peaks in nitrate concentration usually occur. In addition, forest-fire smoke may be a significant contributor to the mountain snow-pack chemistry in some years and must be considered when interpreting the Mt Logan core data. One Yukon profile seems to contain the signature from the 1986 Augustine volcanic eruption.

Some results of glacier mass balance research on the glaciers of the Polar Urals

Abstract: A complete series of mass balance observations made on the IGAN and Obruchev glaciers in the Polar Urals for the 1957/58–1980/81 balance years is presented. The values of the annual and winter mass balances were measured and the summer balance was obtained as their difference. The mean and extreme altitudes of the equilibrium line at the end of the balance year were identified. A satisfactory relationship was demonstrated between the annual balance and the equilibrium line altitude and the percentage share of the accumulation area, i.e., the ratio between the area of the accumulation zone and the total area of the glacier. Changes in winter, summer and annual mass balances with altitude were analyzed over the long term and for years with extreme mass balance values. The IGAN and Stor glaciers were compared in terms of annual, summer, and winter mass balance values. Integral‐differential curves of the type S Ax/a demonstrate opposing trends in the mass balance changes and the mass balance componen...