Hostname: page-component-848d4c4894-tn8tq Total loading time: 0 Render date: 2024-07-06T00:36:34.358Z Has data issue: false hasContentIssue false

Climatic Interpretation of Alpine Snowline Variations on Millennial Time Scales

Published online by Cambridge University Press:  20 January 2017

Abstract

The depression of snowlines, or equilibrium-line altitudes, of alpine glaciers is often used by glacial geologists to infer variations in mass balance. The climatic interpretation of snowline depression, however, is complicated by the number of factors that control glacier mass balance. The simple lapse-rate method of temperature interpretation ignores the effects of changes in radiation and snow accumulation. The statistical approach to temperature interpretation, which regresses precipitation and temperature against snowline altitude, neglects the effect of radiation. The most comprehensive approach for the climatic interpretation of snowline depression couples the heat and mass balances of a glacier surface. A sensitivity analysis that utilizes the coupled heat- and mass-balance approach indicates that the ∼1000-m variation in snowline of alpine glaciers on glacial-to-interglacial time scales could be a result of significant changes in temperature, and to a lesser extent changes in insolation. Snowline variations are sensitive only to relatively large changes in annual accumulation, which should also be evident in other proxy records of moisture change. The approaches outlined here provide glacial geologists with a summary of how various climatic forcings associated with glaciation may be quantified from snowline data.

Type
Articles
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Berger, A. L. (1978). Long-term variations of caloric insolation resulting from the Earth’s orbital elements. Quaternary Research 9, 139167.Google Scholar
Braithwaite, R. J., and Olesen, O. B. (1990). A simple energy-balance model to calculate ice ablation at the margin of the Greenland ice sheet. Journal of Glaciology 36, 222228.Google Scholar
Hastenrath, S. (1971). On the Pleistocene snow-line depression in the arid regions of the South American Andes. Journal of Glaciology 10, 255267.CrossRefGoogle Scholar
Kuhn, M. (1979). On the computation of heat transfer coefficients from energy-balance gradients on a glacier. Journal of Glaciology 22, 263272.Google Scholar
Kuhn, M. (1989). The response of the equilibrium line altitude to climate fluctuations: Theory and observations. In “Glacier Fluctuations and Climatic Change” (Oerlemans, J., Ed.), pp. 407417. Kluwer Academic, Dordrecht.Google Scholar
Leonard, E. M. (1989). Climatic change in the Colorado Rocky Mountains: Estimates based on modem climate at late Pleistocene equilibrium lines, Arctic and Alpine Research 21, 245255 CrossRefGoogle Scholar
Mears, B. Jr., (1981). Periglacial wedges and the late Pleistocene environment of Wyoming’s intermontane basins. Quaternary Research 15, 171198.CrossRefGoogle Scholar
Miller, G. H., and de Vernal, A. (1992). Will greenhouse warming lead to Northern Hemisphere ice-sheet growth? Nature 355, 244246.Google Scholar
Ohmura, A. Kasser, P., and Funk, M, (1992). Climate at the equilibrium line of glaciers. Journal of Glaciology 38, 397411.CrossRefGoogle Scholar
Porter, S. C. (1977). Present and past glaciation threshold in the Cascade Range, Washington, U.S.A.: Topographic and climatic controls, and paleoclimatic implications. Journal of Glaciology 18, 101116.Google Scholar
Porter, S. C. Pierce, K. L., and Hamilton, T. D. (1983). Late Wisconsin mountain glaciation in the western United States. In “Late Qua-ternary Environments of the United States. Vol. 1. The Late Pleistocene” (Porter, S. C., Ed.), pp. 71111. Univ. of Minnesota Press, Minneapolis.Google Scholar