Glacial Inception on Baffin Island: The Role of Insolation, Meteorology, and Topography
Author(s)
Birch, Leah; Tziperman, Eli; Cronin, Timothy Wallace
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Geologic evidence suggests that the last glacial inception (115 kya) occurred within the mountains of Baffin Island. Global climate models (GCMs) have difficulty simulating this climate transition, likely because of their coarse horizontal resolution that smooths topography and necessitates the use of cumulus parameterizations. A regional configuration of the Weather Research and Forecasting (WRF) Model is used to simulate the small-scale topographic and cloud processes neglected by GCMs, and the sensitivity of the region to Milankovitch forcing, topography, and meteorology is tested. It is found that ice growth is possible with 115-kya insolation, realistic topography, and slightly colder-than-average meteorology, represented by specific years within the past three decades. The simulation with low GCM-like topography shows a negative surface mass balance, even with the relevant orbital parameter configuration, demonstrating the criticality of realistic topography. The downslope growth of the ice sheets is studied by looking at the sensitivity of the mass balance to initial snow cover prescribed beyond that of the present day. It is found that the snow-albedo feedback, via its effects on the mass balance, allows such larger snow cover to persist. Implications for GCM studies of glacial inception are discussed. Keywords: Climate change; Climate variability; Glaciation; Paleoclimate
Date issued
2017-05Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary SciencesJournal
Journal of Climate
Publisher
American Meteorological Society
Citation
Birch, Leah et al. “Glacial Inception on Baffin Island: The Role of Insolation, Meteorology, and Topography.” Journal of Climate 30, 11 (June 2017): 4047–4064 © 2017 American Meteorological Society
Version: Final published version
ISSN
0894-8755
1520-0442