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James A. Renwick, Alison Kohout, and Sam Dean

1. Introduction The annual cycle of Antarctic sea ice extent is one of the largest seasonal variations on Earth. The maximum areal extent varies by a factor of 5, from ~4 million km 2 in late summer to ~19 million km 2 in late winter, effectively doubling the ice-covered area of Antarctica from minimum to maximum extent ( Thomas and Dieckmann 2003 ; Wadhams 2000 ). Moreover, sea ice in the Antarctic grows around the perimeter of a continent, unconstrained in the equatorward direction by any

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Ryu Saiki and Humio Mitsudera

1. Introduction A plumelike structure of sea ice often appears in the marginal ice zone (MIZ) in polar oceans ( Fig. 1 ). This organized structure of sea ice is called an ice band. Formation of ice bands causes increases in the area of open water in MIZ, and rapid melting may be promoted. Therefore, it has been suggested that the seasonal evolution of the MIZ is likely influenced by ice-band pattern formation (e.g., Martin et al. 1983 ). Fig . 1. Satellite images of ice-band patterns from

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Jerry X. Mitrovica, Carling C. Hay, Robert E. Kopp, Christopher Harig, and Konstantin Latychev

1. Introduction A number of factors contribute to the geographic variability of sea level change, including changes in ocean dynamics, thermosteric effects, land water storage, local vertical land movement due to tectonics and sediment compaction, and the melting of glaciers and ice sheets ( Milne et al. 2009 ), all of which are superimposed on large-scale, long-term geographic trends associated with ongoing glacial isostatic adjustment ( Peltier 2004 ; Lambeck et al. 2014 ). The impact of

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Keith Jackson, Jeremy Wilkinson, Ted Maksym, David Meldrum, Justin Beckers, Christian Haas, and David Mackenzie

1. Introduction This paper describes the development of a new ice mass balance (IMB) buoy that uses the established principle of measuring temperatures at closely spaced intervals down a chain of sensors deployed through sea ice. However, this new IMB buoy uses a novel construction method for the chain that allows opportunities for dramatic reduction in cost and complexity compared to previous thermistor chain designs. Also, we describe a heated anemometer mode that allows for identification of

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Xiaodan Chen, Dehai Luo, Steven B. Feldstein, and Sukyoung Lee

1. Introduction Over the past decade, Arctic sea ice extent has been observed to undergo a marked decline since the early 2000s ( Comiso 2006 ; Francis and Hunter 2007 ; Screen and Simmonds 2010a , b ; Simmonds 2015 ). Because Northern Hemisphere midlatitude extreme cold events in winter ( Screen and Simmonds 2013a , b ; Cohen et al. 2014 ), habitat ecosystems ( Forbes et al. 2016 ), and increased coastal erosion and changes to the ocean circulation have been shown to be closely related to

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Yi-Ching Chung, Stéphane Bélair, and Jocelyn Mailhot

1. Introduction As part of the Arctic system, snow-covering sea ice has long been recognized to be crucial in coupled ocean–ice–atmosphere models ( Maykut and Untersteiner 1971 ; Ledley 1991 ; Ebert and Curry 1993 ). Snow mainly has two large but opposite effects on the energy and mass balance of the ice floe in the Arctic Ocean. The first effect is related to the snow high albedo, which leads to significant solar radiation reflection back to the atmosphere, delaying the spring snowmelt

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Alexander B. Rabinovich, Georgy V. Shevchenko, and Richard E. Thomson

Island in the Sea of Okhotsk and moored current meter data on the west coast of Canada. Results for the sea ice data only are reported in this study ( section 4 ). Comparison of our four-parameter vector regression model and the more traditional two-parameter complex transfer function model for ice-drift data enables us to characterize the advantages and limitations of each model. The main results are discussed in section 5 . 2. Vector regressional model The effect of coastlines on winds and wind

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Haruhiko Kashiwase, Kay I. Ohshima, Yasushi Fukamachi, Sohey Nihashi, and Takeshi Tamura

1. Introduction Sea ice production in coastal polynyas is a key process in the global climate system. Coastal polynyas are areas of thin ice or open water sustained by divergent ice motion due to wind and ocean currents ( Barber and Massom 2007 ). During the winter, heat loss in coastal polynyas is one or two orders of magnitude greater than that in the surrounding thicker sea ice areas ( Maykut 1978 ), and high ice production occurs in such limited areas. A large coastal polynya frequently

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Hangzhou Wang, Ying Chen, Hong Song, and Samuel R. Laney

1. Introduction Photosynthetic algae are a key component of sea ice ecosystems. Rich algal communities can be found in melt ponds that form on the ice or snow surface, in complex brine networks internal to the porous ice itself, in layers attached to the bottom of sea ice, and in the water column immediately below ( Arrigo and Thomas 2004 ). The biomass, taxonomic composition, and photosynthetic behavior of these algal communities are each shaped by complex interactions between incident solar

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Russell Blackport and James A. Screen

1. Introduction The Arctic has warmed rapidly over recent decades, concomitant with sea ice loss ( Stroeve and Notz 2018 ) that is already having large impacts on the local climate and ecosystems ( Meier et al. 2014 ). Changes in Arctic sea ice have the potential to influence midlatitude weather and climate, but there is low confidence in the detection of this influence for specific weather types ( Cohen et al. 2014 ; Barnes and Screen 2015 ; Francis 2017 ; Screen et al. 2018 ; Vavrus 2018

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