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R. G. Graversen

ice volume has decreased by 40% relative to the situation prevalent from the 1940s through the 1970s ( Rothrock et al. 1999 ). Rigor et al. (2002) report that, in both the summer and winter season, changes of the wind stress might have given rise to larger areas with thin ice and leads in the eastern part of the Arctic Ocean that, in turn, possibly have contributed to the observed warming there. In the winter season, the changes of the wind stress are related to changes of the Arctic Oscillation

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Masayo Ogi, Bunmei Taguchi, Meiji Honda, David G. Barber, and Søren Rysgaard

). Regarding such atmospheric forcing on different seasons, Ogi and Tachibana (2006) showed that an annual-mean atmospheric pattern defined as the January–December mean Arctic Oscillation (AO) pattern ( Thompson and Wallace 1998 ) is significantly related to both the summer discharge of the Amur River and sea-ice extent in the Okhotsk Sea in the following winter. This study indicated that atmospheric patterns on the annual time scale could influence the season-to-season link of the atmosphere

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R. R. Dickson, T. J. Osborn, J. W. Hurrell, J. Meincke, J. Blindheim, B. Adlandsvik, T. Vinje, G. Alekseev, and W. Maslowski

(1998 , 2000 ; Thompson et al. 2000) suggested that the NAO may be the regional manifestation of an annular (zonally symmetric) hemispheric mode of variability characterized by a seesaw of atmospheric mass between the polar cap and the middle latitudes in both the Atlantic and Pacific Ocean basins. A very similar structure is also evident in the Southern Hemisphere. They named this mode the Arctic Oscillation (AO) and showed that, during winter, its vertical structure extends deep into the

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Linhao Zhong, Lijuan Hua, and Dehai Luo

contributes the most significantly to the BKS sea ice melting and warming because there is almost no concurrent downward IR increase found ( Fig. 8c ), which again suggests that the high local moisture contribution is only a manifestation of the sea ice melting. Corresponding to high local moisture contribution, the circulation ( Fig. 8d ) has a negative-phase Arctic Oscillation (AO−)-like pattern with an eastward-displaced positive anomaly that partly covers the BKS and with two negative anomalies

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Claude Frankignoul, Nathalie Sennéchael, and Pierre Cauchy

1. Introduction There is increasing evidence that the seasonal to decadal sea ice changes superimposed on the observed decline in Arctic sea ice cover affect the atmospheric circulation. Model studies have suggested that North Atlantic sea ice anomalies influence the North Atlantic Oscillation (NAO)/Arctic Oscillation (AO) and the North Atlantic storm track ( Magnusdottir et al. 2004 ; Alexander et al. 2004 ; Kvamstø et al. 2004 ), while North Pacific sea ice primarily influences the

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Cecilia Peralta-Ferriz, James H. Morison, John M. Wallace, Jennifer A. Bonin, and Jinlun Zhang

concern given their possible linkages with global climate, for example by controlling stratification in the sub-Arctic seas and thereby modulating convection and the meridional overturning circulation ( Aagaard and Carmack 1989 ; Hu et al. 2010 ). These changes have been linked to the Arctic Ocean circulation and climate variability ( Morison et al. 2000 , 2006 ). During the late 1980s and early 1990s, the leading mode of hemispheric surface atmospheric pressure, the Arctic Oscillation (AO

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R. Kwok

, between Svalbard and Fraz Josef Land (S–FJL) and between Franz Josef Land and Severnaya Zemlya (FJL–SZ), into the Barents Sea. Section 5 discusses the net sea ice outflow into the Greenland and Barents Seas and considers how the outflows are related to changes in the sea ice circulation pattern in the Arctic Ocean and indices of atmospheric oscillations. The last section concludes the paper. 2. Motion fields, flux estimates, and ancillary data To estimate the outflow of Arctic sea ice into the

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Josefino C. Comiso

since some wind patterns are favorable to the advection of multiyear or thick ice through Fram Strait and eventually to the Atlantic Ocean where they melt. Such events could cause significant interannual changes in the extent of the multiyear ice cover. It has been postulated by Thompson and Wallace (1998) that the atmospheric circulation pattern in the Arctic is controlled by the Arctic Oscillation (AO). The AO has been quantified through the use of AO indices, which are the differences in the

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Robert X. Black

1. Introduction It is becoming increasingly evident that longitudinally symmetric (or annular) modes of atmospheric variability, such as the Arctic oscillation (AO), strongly influence surface climate variability at mid- and high latitudes ( Thompson and Wallace 1998 ; Kerr 1999 ; Hartmann et al. 2000 ). In particular, the AO accounts for a large fraction of recent decadal climate trends in the northern high latitudes ( Hurrell 1995 ; Thompson et al. 2000 ). Thus, a thorough understanding of

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Hai Lin

major circulation pattern in the extratropical Northern Hemisphere that is relevant to polar prediction is the northern annular mode (NAM) or the Arctic Oscillation (AO; e.g., Thompson and Wallace 1998 , 2000 ), which is characterized by an out-of-phase change in sea level pressure between the Arctic and the midlatitudes. The North Atlantic Oscillation (NAO; e.g., Hurrell et al. 2003 ), an important mode of variability influencing the weather and climate in eastern North America and Europe, is a

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