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Andreas Schmittner, Tiago A. M. Silva, Klaus Fraedrich, Edilbert Kirk, and Frank Lunkeit

( Schmittner et al. 2005 ). Here we attempt to further our understanding of the processes that drive the ocean circulation in coupled ocean–atmosphere models by studying the orographic effects of mountains and ice sheets. Model studies of the effects of mountains on the atmospheric circulation and climate have a long tradition ( Kitoh 2002 ; Manabe and Terpstra 1974 ); however, to our knowledge, no study to date has investigated the effects on the global ocean circulation. We will show that mountains and

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Diandong Ren, Rong Fu, Lance M. Leslie, Jianli Chen, Clark R. Wilson, and David J. Karoly

1. Introduction The Greenland Ice Sheet (GrIS), because of its large size, unique location, and strong thermal contrast with adjacent open waters, has a strong influence on large-scale atmospheric variations ( Wallace 2000 ; Bromwich et al. 1999 ), and its melting has a potential influence on global sea level rise ( Yin et al. 2009 ). Its response to a warming climate and the resultant influence on global and regional climate is widely acknowledged ( Thomas 2001 ; Steffen and Box 2001

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Edward Hanna, Philippe Huybrechts, Konrad Steffen, John Cappelen, Russell Huff, Christopher Shuman, Tristram Irvine-Fynn, Stephen Wise, and Michael Griffiths

1. Introduction The Greenland Ice Sheet (GrIS) contains ∼7.4-m global sea level equivalent and is vulnerable to ongoing anthropogenic climate change ( Gregory et al. 2004 ). Therefore, it is essential to establish its current state of mass balance and climatic sensitivity, and detect any warning signs that might be a guide to its future response. Observationally based studies have provided intriguing insights into recent mass balance changes of the GrIS. Airborne and satellite laser

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Jeremy G. Fyke, Lionel Carter, Andrew Mackintosh, Andrew J. Weaver, and Katrin J. Meissner

1. Introduction Ice shelves and ice sheets evolve in response to changes in oceanic and atmospheric boundary conditions. Recent dramatic losses of long-lived ice shelves in both hemispheres highlight the uniqueness of recent climate change and have focused attention on causal factors that promote ice shelf retreat. Ice shelves respond dynamically and thermodynamically to changes in underlying ocean temperature ( Holland et al. 2008a ) and surface air temperature (SAT). Several authors (e

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William H. Lipscomb, Jeremy G. Fyke, Miren Vizcaíno, William J. Sacks, Jon Wolfe, Mariana Vertenstein, Anthony Craig, Erik Kluzek, and David M. Lawrence

1. Introduction Most global climate models have not included interactive ice sheet models, in part because ice sheets were once thought to evolve only on time scales of centuries to millennia. Recent observations, however, have shown that ice sheets can respond to ocean and atmospheric changes on annual-to-decadal time scales and that mass loss from the Greenland and Antarctic Ice Sheets has increased since the 1990s. In Greenland, atmospheric warming has led to greater mass loss through

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Jason E. Box and William Colgan

1. Introduction Ice sheet mass balance exerts a significant influence on global mean sea level (e.g., Huybrechts et al. 2004 ; Church and White 2011 ), thermohaline circulation (e.g., Fichefet et al. 2003 ; Rahmstorf et al. 2005 ), and ocean sediment nutrient influx ( Rysgaard et al. 2003 ; Hasholt et al. 2006 ). A likely global sea level rise of 1 m or more by the century's end (e.g., Pfeffer et al. 2008 ) will come at massive infrastructural and livelihood costs. Ice flowing into the

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Jason E. Box

1. Introduction Ice sheet mass balance ( B ) exerts a significant influence on global mean sea level (e.g., Church and White 2011 ), thermohaline circulation (e.g., Fichefet et al. 2003 ; Rahmstorf et al. 2005 ), and ocean sediment nutrient influx ( Rysgaard et al. 2003 ; Hasholt et al. 2006 ). The B is often decomposed among 1) mass fluxes originating at the surface–atmosphere interface (the climatic surface mass balance including internal accumulation), hereafter B clim ( Cogley et al

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

frequency phenomena (such as baroclinic eddies in the atmosphere) result in a coherent regional forcing of low-frequency climate variability that is fundamentally nonrandom even though they act on disparate time scales. In contrast, there is a relative absence of high to low frequency coupled studies that deal with cryospheric processes. However, this technique has considerable potential for untangling the dynamic history of massive continental ice sheets in the earth’s past since glacial inception

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Yu Gao, Zhengyu Liu, and Zhengyao Lu

1. Introduction Continental ice sheets have experienced large glacial–interglacial cycles in the last 2 million years during the Pleistocene. At their maximum, such as the Last Glacial Maximum (LGM) (21 000 years ago), the Laurentide Ice Sheet (LIS) covered much of North America and extended southward to approximately 40°N, while the Eurasian Ice Sheet (EIS) covered much of northern Europe. These ice sheets can reach a height of 3–4 km with a total volume equivalent to ~130 m in global sea

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Sebastian H. Mernild, Glen E. Liston, Christopher A. Hiemstra, and Konrad Steffen

1. Introduction Greenland is the world’s largest island, and the Greenland Ice Sheet (GrIS) is the Northern Hemisphere’s largest terrestrial permanent ice- and snow-covered area. Ice mass and snow cover serve as water reservoirs that are highly vulnerable to ongoing climatic variations and change (e.g., Hanna et al. 2005 ; Hinzman et al. 2005 ). The climate is changing: The average surface air temperature north of 60°N has increased by ∼0.09°C decade −1 , and this change is conspicuous in

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