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Michael S. Pritchard, Andrew B. G. Bush, and Shawn J. Marshall

earth’s past. A variety of modern observations indicate that, during boreal wintertime, Alaska and western Canada experience warmer weather during El Niño while cooler, wetter conditions prevail over the eastern seaboard ( Rasmusson and Carpenter 1982 ). Modest regional extratropical teleconnections also exist during summer but are generally weaker. Changes in moisture and temperature are accompanied by large-scale spatial anomalies in the midtropospheric geopotential height field that appear to be

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Shawn J. Marshall and Martin J. Sharp

field descends to sea level on the east coast of Ellesmere Island and it terminates terrestrially on its western margin, at altitudes of 400 to 650 m. This asymmetry is due to a strong east–west gradient in the ice field’s snow accumulation regime, with southeasterly storm tracks from Baffin Bay providing the primary source of moisture for the ice field ( Koerner 1979 ). The observational network consists of two east–west lines crossing the ice field, one in the north (the NPOW line) and one in the

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M. Eby, K. Zickfeld, A. Montenegro, D. Archer, K. J. Meissner, and A. J. Weaver

transport. For diapycnal mixing, a horizontally constant profile of diffusivity is applied, with values of about 0.3 10 −4 m 2 s −1 in the pycnocline. The ocean model is coupled to a dynamic–thermodynamic sea ice model and an energy–moisture balance model of the atmosphere with dynamical feedbacks ( Weaver et al. 2001 ). The land surface and terrestrial vegetation components are represented by a simplified version of the Hadley Centre Met Office surface exchange scheme (MOSES) coupled to the Top

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Marc d’Orgeville and W. Richard Peltier

intrinsic feature of the snow and sea ice dynamics alone but rather the result of the change in the climatic conditions of the region. The positive snow anomaly in the Rocky Mountains, which originates around lags −4 and −2 yr, is presumably due to the combination of the warmer SST in the western Pacific and the colder air above the Rocky Mountains (not shown). First, an excess of evaporation, resulting from the warmer SST, increases the moisture in the air (originating from the western Pacific Ocean

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J. Paul Spence, Michael Eby, and Andrew J. Weaver

-conserving ice–snow thermodynamics with a two-category thickness distribution ( Hibler 1979 ) and an elastic–viscous–plastic rheology ( Hunke and Dukowicz 1997 ). The model predicts ice thickness, areal fraction, and surface temperature. The UVic ESCM employs a vertically integrated energy–moisture balance atmospheric model for computational efficiency. Precipitation occurs when the relative humidity exceeds 90%, and on land it is treated by a simple bucket model described in Matthews et al. (2003) . The

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Alex S. Gardner, Martin J. Sharp, Roy M. Koerner, Claude Labine, Sarah Boon, Shawn J. Marshall, David O. Burgess, and David Lewis

different temperatures and moisture contents, by forcing the ascent/descent of advected air masses over terrain and by altering the turbulent heat fluxes between the free atmosphere and the surface. However, no consistent relationships were found between wind components and lapse rates. Daily average time series for the selected NARR variables were created for each glacier by averaging over a six-gridcell domain (96 km by 64 km) centered over each glacier. All time series were generated for the period

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Garry K. C. Clarke, Andrew B. G. Bush, and John W. M. Bush

. Ellison , C. R. W. , M. R. Chapman , and I. R. Hall , 2006 : Surface and deep ocean interactions during the cold climate event 8200 years ago. Science , 312 , 1929 – 1932 . EPICA Community Members, and Coauthors , 2006 : One-to-one coupling of glacial climate variability in Greenland and Antarctica. Nature , 444 , 195 – 198 . Fanning , A. F. , and A. J. Weaver , 1996 : An atmospheric energy–moisture balance model: Climatology, interpentadal climate change, and coupling to an

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