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

important oceanic processes are not adequately represented at coarse (>1°) resolution. For example, the widths of boundary currents are overestimated, while their speeds are underestimated, and the influence of mesoscale eddies are fairly crudely parameterized. The Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR) warned that model results reliant on meridional heat transports with >1° resolution ocean components should be treated cautiously ( McAvaney et al. 2001 ). The

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Marc d’Orgeville and W. Richard Peltier

first EOF of V tb is trapped in the western boundary current and has a weaker maximum of time-lag correlation with the first EOF of BSF. c. Conclusions on the surface variability Taking into account that in 1870-control, as compared to 1990-control, more sea ice is present and the subpolar gyre is weaker ( section 4 ), it seems evident that the difference of mean state between the two simulations is responsible for enabling these differences in surface variability. First, the increased sea ice

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

longitudinal transect of the Atlantic Basin at 30°N ( Fig. 3 ). A number of features in the evolution of the Atlantic Ocean general circulation can be recognized in Fig. 3 . Prior to the FWF event ( Fig. 3a ), the western boundary current is characterized by the strong localized northward transport of warm, saline waters at, and near, the surface (the Gulf Stream) with a deep western boundary current of strong, cold southward flow found between a depth of 1000 and 2500 m. The Atlantic subtropical gyre is

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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

performed either by running a regional climate model (forced at its boundaries with coarse-resolution climate model output or data from climate reanalysis) at the desired resolution or by computing near-surface temperatures from climate model fields using a digital elevation model of the glacier surface and an assumed temperature lapse rate. “Lapse rate” is defined as “the decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified” ( Glickman 2000 ), and

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

– 318 . Chapman , D. C. , 2000 : A numerical study of the adjustment of a narrow stratified current over a sloping bottom. J. Phys. Oceanogr. , 30 , 2927 – 2940 . Chapman , D. C. , and S. J. Lentz , 1994 : Trapping of a coastal density front by the bottom boundary layer. J. Phys. Oceanogr. , 24 , 1464 – 1479 . Clark , P. U. , S. J. Marshall , G. K. C. Clarke , S. W. Hostetler , J. M. Licciardi , and J. T. Teller , 2001 : Freshwater forcing of abrupt climate change

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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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Marc d’Orgeville and W. Richard Peltier

losing heat before a positive phase of the PDO; the water advected by the western boundary current of the subpolar gyre from the Bering Sea to the Kuroshio region loses heat and is therefore unlikely to be able to explain the positive SST anomaly of the PDO. The reason for the phase lag between the Bering Sea heat flux and the PDO will be further explored in the next section. The spatial patterns of FWFX1 and SSS1 display a spatial correspondence ( Fig. 6 ) with negative (positive) freshwater flux

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Stephen D. Griffiths and W. Richard Peltier

1. Introduction Tides occur throughout the oceans as periodic oscillations in currents and sea surface height, typically with diurnal or semidiurnal time scales. The amplitude of the surface oscillations is about 50 cm over much of the open ocean and about 1 m along many coastlines, but local resonances can lead to tides of over 5 m in special coastal locations (e.g., Garrett 1972 ; Arbic et al. 2007 ). However, tidal amplitudes are sensitive to the frequency of the lunar and solar forcing (i

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A. E. Viau and K. Gajewski

well as during the more recent Little Ice Age (LIA) and Medieval Warm Period (MWP) of the past 1000 yr ( Gajewski 1987 ; Viau et al. 2006 ). Thus, regional millennial to centennial climate changes are important, particularly because they are relevant to understanding the current global warming issues. However, regional syntheses of the time–space evolution of the climate are lacking. Much of the recent interest in millennial-scale climate variability has centered on analysis of ice core and marine

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

and Clarke (1997) and Marshall et al. (2002) . Briefly, the model employs a set of rheologically constrained conservation equations for energy, mass, and momentum in order to simulate the large-scale diffusion of mass ( Mahaffy 1976 ) and heat ( Jenssen 1977 ) within the ice sheet. The ice flows according to viscous creep dynamics (neglecting the effects of longitudinal stresses), with a parameterization for basal sliding, introduced as a basal boundary condition and activated when the ice is

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