Ice layers as an indicator of summer warmth and atmospheric blocking in Alaska

Abstract

Samples were collected from a snow pit and shallow firn core near Kahiltna Pass (2970 ma.s.l.), Denali National Park, Alaska, USA, in May 2008. The record spans autumn 2003 to spring 2008 and reveals clusters of ice layers interpreted as summertime intervals of above-freezing temperatures. High correlation coefficients (0.75–1.00) between annual ice-layer thickness and regional summertime station temperatures for 4 years (n=4) indicate ice-layer thickness is a good proxy for mean and extreme summertime temperatures across Alaska, at least over the short period of record. A Rex-block (aka high-over-low) pattern, a downstream trough over Hudson Bay, Canada, and an upstream trough over eastern Siberia occurred during the three melting events that lasted at least 2 weeks. About half of all shorter melting events were associated with a cut-off low traversing the Gulf of Alaska. We hypothesize that a surface-to-bedrock core extracted from this location would provide a high-quality record of summer temperature and atmospheric blocking variability for the last several hundred years.

Department

Earth Sciences, Earth Systems Research Center

Publication Date

10-2010

Journal Title

Journal of Glaciology

Publisher

International Glaciological Society

Digital Object Identifier (DOI)

10.3189/002214310793146214

Document Type

Article

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