CGRG Bibliography of Canadian Geomorphology
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Author : Boon, S.
Date : 2006.
Title : Modelling Arctic glacier response to climate change.
Publication : Annual Scientific Meeting of the Canadian Geophysical Meeting, May 14-17, 2006. Banff Centre, Banff, Alberta. Abstracts Volume.
Issue :
Page(s) : 17-18.
Abstract
Glaciologists use degree-day models (DDMs) to quantify annual mass change in glaciated regions; results are often applied on a large scale to assess climate impacts and assist in making policy decisions (e.g., Houghton et al., 2001; ACIA, 2004). It is therefore imperative to quantify the impact of both DDM structure and assumptions on DDM performance. This paper first presents results from an investigation of the sensitivity of model output to parameterization of: (a) temperature and accumulation lapse rates; and, (b) refreezing processes and summer snowfalls. It then investigates the predicted response of Arctic glacier melt, runoff and MB to climate changes using composite output from an ensemble of global climate models (GCMs). Results indicate that output from the selected DDM is particularly sensitive to the parameterization of environmental lapse rates (accumulation and air temperature), suggesting that field-measured values of these parameters are critical to accurately determine glacier-climate response. Given this sensitivity, the DDM was initialized and calibrated with 2001 field data, including measured lapse rate values. Using information from the composite output of eight GCMs, the 2001 baseline model run was subjected to: (1) an increase in summer air temperature; (2) an increase in winter precipitation; (3) an increase in summer precipitation; and, (4) a concurrent increase in both winter precipitation and summer air temperature. Model output from each climate scenario indicates that an increase in summer air temperature has the greatest impact on glacier mass balance, while the predicted winter accumulation increase does little to offset the impact of an increase in summer air temperature. Additionally, summer precipitation events can reduce annual mass balance by initiating refreezing events during the melt season. These results compare well with conclusions reached by other researchers, and emphasize the importance of using field-measured environmental lapse rates in calculating annual MB.
Bibliography of Canadian Geomorphology