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Marc d’Orgeville and W. Richard Peltier

fluxes is related to the ocean variability in section 4 . Section 5 displays a typical evolution of the PDO from the surface, and section 6 discusses the origins of the PDO time scale in our simulations. Finally, the effect of global warming on North Pacific decadal variability is examined in section 7 . Section 8 summarizes our findings and provides a discussion of their implications. 2. Numerical experiments and analysis procedures a. The coupled atmosphere–ocean climate model The model

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Marc d’Orgeville and W. Richard Peltier

four interacting components—atmosphere, ocean, sea ice, and land surface—linked via a flux coupler. All of the simulations discussed in the following have been performed at T31 resolution for the atmospheric component (26 vertical levels and 3.75° horizontal resolution) and with a grid termed gx3v5 for the oceanic component (25 vertical levels, 3.6° resolution in the zonal direction and variable in the meridional direction with approximately 0.6° resolution near the equator). In gx3v5, because 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

the major energy fluxes to and from the glacier surface in order to determine the energy available for melt. In either case, spatially distributed modeling is required to capture spatial and temporal patterns of surface melt ( Glover 1999 ; Arnold et al. 2006 ). Such modeling requires accurate downscaling of coarse-resolution temperature fields derived from climate models or reanalysis to produce near-surface air temperature fields with an appropriate spatial resolution. Downscaling can be

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

-down Representation of Interactive Foliage and Flora Including Dynamic vegetation model; Meissner et al. 2003 ). Land carbon fluxes are calculated within MOSES and are allocated to vegetation and soil carbon pools ( Matthews et al. 2004 ). Ocean carbon is simulated by means of an Ocean Carbon-Cycle Model Intercomparison Project type inorganic carbon cycle model and a nutrient–phytoplankton–zooplankton–detritus marine ecosystem model ( Schmittner et al. 2008 ). Sediment processes are represented using an oxic

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

, an increased freshwater flux creates more stably stratified surface water, which reduces deep water formation and its concomitant meridional heat transport, producing a cooling of Northern Hemisphere climate. Because the deep ocean requires centuries to millennia to reach a thermodynamic equilibrium ( Broecker 1991 ), computational constraints have historically limited the horizontal resolution of models used in previous studies to greater than 1° (latitude) × 1° (longitude). A number of

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Guido Vettoretti, Marc d’Orgeville, William R. Peltier, and Marek Stastna

coupled atmosphere–ocean scenarios. In a recent study, Wu et al. (2008) investigate in detail the teleconnections from the North Atlantic to the tropical Pacific during an AMOC reduction. This study notes a mechanism for the propagation of North Pacific cooling along Baja California into the western tropical Pacific during a freshwater flux (FWF) event. Our purpose in this paper is to explore the impact of one specific agent of glacial climate change on the ENSO process, namely high-latitude cooling

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Garry K. C. Clarke, Etienne Berthier, Christian G. Schoof, and Alexander H. Jarosch

flux can be calculated and the balance flux can be inverted to ice thickness using Glen’s flow law ( Huss et al. 2008 ). A shortcoming of the volume–area scaling approach is that it yields no useful information about subglacial topography—a necessary boundary condition for glacier dynamics models. In contrast, the physics-based methods allow ice thickness to be estimated but are subject to error if their underlying assumptions are not fulfilled. This motivates our interest in a fresh approach to

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

.g., Thomas et al. 2007 ) and spatial heterogeneity of the terrestrial signal ( Seppä et al. 2007 ). For recent reviews see Alley and Ágústsdóttir (2005) and Rohling and Pälike (2005) . The cause of the 8.2 ka event remains controversial. A leading explanation is that the convective overturning of the North Atlantic Ocean was affected by the flux of freshwater to the Labrador Sea from the catastrophic drainage of an ice-dammed superlake that formed by the coalescence of glacial lakes Agassiz and

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Shawn J. Marshall and Martin J. Sharp

an effective local source of longwave and sensible heat fluxes that contribute to the high PDD totals. 4. Temperature and melt modeling In general, detailed knowledge of meteorological conditions is unavailable on a glacier or ice field, and positive degree days or the terms in a more rigorous energy balance must be modeled for a region. We restrict our attention to degree-day melt modeling here. This requires a number of characteristics of temperature variability to be characterized for a region

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

, primarily through basal flow. Once triggered, this dynamic flux input facilitates ice growth in newly covered cells by contributing local ice thickness increases much higher than those caused by meteoric accumulation alone. Basal velocities are on the order of 50 m yr −1 at the southern extremity of the existing cordilleran margin ( Fig. 14 , bottom panel). This dynamic input has the capacity to stabilize new ice formed during cold extremes in the interannual record against counteracting ablation

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