CGRG Bibliography of Canadian Geomorphology
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Author : Field, R.; Moore, K.; and Holdsworth, G.
Date : 2007.
Title : Modeling stable water isotope composition using GCMs as a tool to understand the climate signals in ice cores.
Publication : CMOS, CGU, AMS Congress 2007. "Air, Ocean, Earth and Ice on the Rock". May 28 - June 1, 2007. St. John's Congress Centre, Newfoundland and Labrador, Canada.
Issue :
Page(s) : C02-2C5.3.
Abstract
The stable water isotope (SWI) composition of ice cores is conventionally assumed to provide a method of temperature reconstruction because of the temperature dependence of isotope fractionation when water forms in clouds. The isotope fractionation is also influenced, however, by the conditions under which the moisture originally evaporated and its transport between source and deposition regions. This complicates the use of ice cores as indicators of local climate, but also makes them useful as proxies of broader circulation patterns. The goal of our work is to better understand what controls the SWI composition of precipitation in the southwestern Yukon, and in particular, to better-interpret the SWI signal from the Mount Logan ice core. To this end, we are conducting experiments with the GISS ModelE general circulation model, which is equipped with SWI diagnostics. Preliminary results show that the model performs well in capturing regional and seasonal SWI variation at selected sites in Canada. In the Yukon, SWI variability is controlled by both the local temperature as well as large-scale circulation anomalies such as the Pacific North America teleconnection pattern and ENSO. The strength of these relationships is highly dependent on seasonality, which provides a possible explanation for the lack of circulation signals detected thus far in the Mt. Logan ice core.
Bibliography of Canadian Geomorphology