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A. V. Pnyushkov
and
I. V. Polyakov

1. Introduction This paper discusses the properties of tidally induced currents derived from two year-long acoustic Doppler current profiler (ADCP) records from the mooring located at the continental slope of the Laptev Sea in the Arctic Ocean in 2004–05 and 2005–06. Recent Arctic Ocean Model Intercomparison Project (AOMIP) studies suggest that Arctic Ocean modeling may be improved if tides are explicitly included in coupled ice–ocean models ( Holloway and Proshutinsky 2007 ). At the same time

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Igor V. Polyakov
,
Andrey V. Pnyushkov
, and
Leonid A. Timokhov

1. Introduction This analysis has been motivated by the recent study of Bourgain and Gascard (2012) , who analyzed an extensive collection of measurements of intermediate (depth range of ~150–900 m) Atlantic Water (AW; Fig. 1 ) temperatures from 1997 to 2008 and found no AW warming trend in the Eurasian Basin of the Arctic Ocean. AW supplies vast quantities of heat to the Arctic Ocean, and it is still debatable how much of this heat penetrates upward through the stable Arctic halocline and

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Ayan H. Chaudhuri
and
Rui M. Ponte

1. Introduction Sea ice is a key component of the Arctic Ocean physical system and can control the exchange of heat, water, momentum, and gases at the sea surface. Changes in the albedo of the surface brought on by changes in the ice cover over very large areas are a major factor in global climate change. The summer extent of the Arctic sea ice cover, widely recognized as an indicator of climate change ( Hassol 2005 ), has been declining for the past few decades. The ice pack is also thinning

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Achim Randelhoff
,
Ilker Fer
, and
Arild Sundfjord

1. Introduction Stratification, currents, turbulence levels, and vertical mixing in the upper Arctic Ocean are coupled to and affected by the presence of sea ice. The sea ice cover can act like a lid to prevent input of energy from the atmosphere ( Levine et al. 1985 ; Morison et al. 1985 ) and enhance or reduce the near-surface mixing ( Martin et al. 2014 ) by changing the air–ice drag. During summer, when broken-up floes drift relatively freely, sea ice melt increases stratification as this

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John E. Walsh
,
William L. Chapman
, and
Diane H. Portis

1. Introduction Recent climate modeling has demonstrated significant sensitivity of the Arctic to climate change ( Anisimov et al. 2007 ; Kattsov and Källen 2005 ). This sensitivity has been verified with observations. According to the Technical Summary of Working Group I ( Solomon et al. 2007 ) for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4), observed climate change over the last 30 yr has been greatest at northern high latitudes. Average Arctic

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Matthew D. Shupe
,
Von P. Walden
,
Edwin Eloranta
,
Taneil Uttal
,
James R. Campbell
,
Sandra M. Starkweather
, and
Masataka Shiobara

1. Introduction Clouds play an important role in Arctic atmospheric radiation and hydrologic cycles. In addition, complex feedbacks involving clouds have a substantial systemic regional impact on Arctic climate, yet they are not well characterized ( Stephens 2005 ). Clouds may have been influential in recent dramatic Arctic sea ice loss ( Kay et al. 2008 ; Perovich et al. 2008 ; Schweiger et al. 2008 ) and their climate influence is sensitive to changes in atmospheric aerosols (e.g., Sassen

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Alexey Yu. Karpechko
and
Elisa Manzini

). If the BD circulation strengthening extends to the poles (i.e., it encompasses the deep branch of the BD circulation) an equatorward shift of the tropospheric eddy-driven jet streams during Northern Hemisphere (NH) winter is also often simulated ( Scaife et al. 2012 ; Karpechko and Manzini 2012 ), although it is not a robust response across the models. Butchart et al. (2000) reported that the forced response of the Arctic stratosphere to global warming is small compared to internal variability

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Lei Cai
,
Vladimir A. Alexeev
,
John E. Walsh
, and
Uma S. Bhatt

1. Introduction Two leading modes—the Arctic Oscillation (AO) and the Arctic dipole (AD)—contribute the most to the large-scale atmospheric circulation over the Arctic in summer [June–August (JJA)]. By definition, both modes of variability are derived from applying empirical orthogonal function (EOF) analysis to the sea level pressure (SLP) anomaly field. The first EOF mode represents the AO that dominates the atmospheric circulation over the Arctic ( Thompson and Wallace 1998 ; Wu et al. 2006

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Hotaek Park
,
Yasuhiro Yoshikawa
,
Daqing Yang
, and
Kazuhiro Oshima

1. Introduction River water temperature T w is one of the most important parameters affecting freshwater biogeochemistry and the physical properties of surface water in rivers and lakes. The heating and cooling processes of T w in rivers are greatly influenced by meteorological and hydrological conditions over a wide range of spatial and temporal scales. The Arctic rivers are mostly ice covered during winter, with relatively stable T w values, and T w varies significantly during the ice

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I. V. Polyakov
,
V. A. Alexeev
,
G. I. Belchansky
,
I. A. Dmitrenko
,
V. V. Ivanov
,
S. A. Kirillov
,
A. A. Korablev
,
M. Steele
,
L. A. Timokhov
, and
I. Yashayaev

1. Introduction Exchanges between the Arctic and North Atlantic Oceans have a profound influence on the circulation and thermodynamics of each basin ( Aagaard and Carmack 1994 ). The Arctic Ocean is one of the major source regions for the surface waters of the subpolar seas, in which weak stratification leads to deep convection, a key contributor to the global thermohaline circulation ( Dickson et al. 2000 ). Indeed, modeling results provided evidence that the North Atlantic thermohaline

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