12.6 Glacial Inception in North-east Canada: The Role of Topography and Clouds

Thursday, 30 June 2016: 11:45 AM
Adirondack ABC (Hilton Burlington )
Leah Birch, Harvard University, Cambridge, MA; and E. Tziperman and T. Cronin
Manuscript (543.1 kB)

Over the past 2.5 million years, ice ages have dominated Earth's climate. Interglacials, like our current climate, were brief, sometimes lasting only a few thousand years. Mountain glaciers in the Canadian Arctic Archipelago are the last remnants of the Laurentide Ice Sheet, and likely sites of glacial inception. Currently, state-of-the-art global climate models (GCMs) are incapable of simulating the transition of Earth's climate from interglacial to glaciated, which questions the validity of future predictions. We hypothesize that this failure may be related to two aspects of GCMs: their coarse spatial resolution, which does not allow resolving the topography of inception areas, and their parameterized representation of clouds and atmospheric convection. To better understand the small scale topographic and cloud processes mis-represented by GCMs, we run the Weather Research and Forecasting (WRF) atmosphere-land model in a regional, cloud-resolving configuration over the Penny Ice Cap of Baffin Island. Our results show the possibility of ice cap growth on an initially snow-free landscape with realistic topography and insolation values from the last glacial inception. Whereas, smoothed topography as seen in GCMs has a negative surface mass balance, even with the relevant orbital parameter configuration. Our results indicate that increased topographic resolution is paramount to accurate modeling of the Canadian Arctic Archipelago, past and present.
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