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1. Enhanced simulated early 21st century Arctic sea ice loss due to CMIP6 biomass burning emissions

   https://doi.org/10.1126/sciadv.abo2405  

   DeRepentigny, Patricia ; Jahn, Alexandra ; Holland, Marika M. ; Kay, Jennifer E. ; Fasullo, John ; Lamarque, Jean-François ; Tilmes, Simone ; Hannay, Cécile ; Mills, Michael J. ; Bailey, David A. ; et al ( July 2022 , Science Advances)

   The sensitivity of sea ice to fire emissions highlights climate model uncertainty related to the accuracy of prescribed forcings. 

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2. Sea Ice Suppression of CO 2 Outgassing in the West Antarctic Peninsula: Implications For The Evolving Southern Ocean Carbon Sink

   https://doi.org/10.1029/2020GL091835  

   Shadwick, E. H. ; De Meo, O. A. ; Schroeter, S. ; Arroyo, M. C. ; Martinson, D. G. ; Ducklow, H. ( May 2021 , Geophysical Research Letters)

   The Southern Ocean plays an important role in the uptake of atmospheric CO₂. In seasonally ice‐covered regions, estimates of air‐sea exchange remain uncertain in part because of a lack of observations outside the summer season. Here we present new estimates of air‐sea CO₂flux in the West Antarctic Peninsula (WAP) from an autonomous mooring on the continental shelf. In summer, the WAP is a sink for atmospheric CO₂followed by a slow return to atmospheric equilibrium in autumn and winter. Outgassing is almost entirely suppressed by ice cover from June through October, resulting in a modest net annual CO₂sink. Model projections indicate sea ice formation will occur later in the season in the coming decades potentially weakening the net oceanic CO₂sink. Interannual variability in the WAP is significant, highlighting the importance of sustained observations of air‐sea exchange in this rapidly changing region of the Southern Ocean.

    

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3. Antarctic Sea Ice Expansion, Driven by Internal Variability, in the Presence of Increasing Atmospheric CO 2

   https://doi.org/10.1029/2019GL083758  

   Singh, H. A. ; Polvani, L. M. ; Rasch, P. J. ( December 2019 , Geophysical Research Letters)
4. Sea‐ice microbial communities in the Central Arctic Ocean: Limited responses to short‐term pCO2 perturbations

   https://doi.org/10.1002/lno.11690  

   Torstensson, Anders ; Margolin, Andrew R. ; Showalter, Gordon M. ; Smith, Jr, Walker O. ; Shadwick, Elizabeth H. ; Carpenter, Shelly D. ; Bolinesi, Francesco ; Deming, Jody W. ( January 2021 , Limnology and Oceanography)

   The Arctic Ocean is more susceptible to ocean acidification than other marine environments due to its weaker buffering capacity, while its cold surface water with relatively low salinity promotes atmospheric CO₂uptake. We studied how sea‐ice microbial communities in the central Arctic Ocean may be affected by changes in the carbonate system expected as a consequence of ocean acidification. In a series of four experiments during late summer 2018 aboard the icebreakerOden, we addressed microbial growth, production of dissolved organic carbon (DOC) and extracellular polymeric substances (EPS), photosynthetic activity, and bacterial assemblage structure as sea‐ice microbial communities were exposed to elevated partial pressures of CO₂(pCO₂). We incubated intact, bottom ice‐core sections and dislodged, under‐ice algal aggregates (dominated byMelosira arctica) in separate experiments under approximately 400, 650, 1000, and 2000 μatm pCO₂for 10 d under different nutrient regimes. The results indicate that the growth of sea‐ice algae and bacteria was unaffected by these higher pCO₂levels, and concentrations of DOC and EPS were unaffected by a shifted inorganic C/N balance, resulting from the CO₂enrichment. These central Arctic sea‐ice microbial communities thus appear to be largely insensitive to short‐term pCO₂perturbations. Given the natural, seasonally driven fluctuations in the carbonate system of sea ice, its resident microorganisms may be sufficiently tolerant of large variations in pCO₂and thus less vulnerable than pelagic communities to the impacts of ocean acidification, increasing the ecological importance of sea‐ice microorganisms even as the loss of Arctic sea ice continues.

    

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5. Sub-kilometre scale distribution of snow depth on Arctic sea ice from Soviet drifting stations

   https://doi.org/10.1017/jog.2022.18  

   Mallett, Robbie D. ; Stroeve, Julienne C. ; Tsamados, Michel ; Willatt, Rosemary ; Newman, Thomas ; Nandan, Vishnu ; Landy, Jack C. ; Itkin, Polona ; Oggier, Marc ; Jaggi, Matthias ; et al ( April 2022 , Journal of Glaciology)

   Abstract The sub-kilometre scale distribution of snow depth on Arctic sea ice impacts atmosphere-ice fluxes of energy and mass, and is of importance for satellite estimates of sea-ice thickness from both radar and lidar altimeters. While information about the mean of this distribution is increasingly available from modelling and remote sensing, the full distribution cannot yet be resolved. We analyse 33 539 snow depth measurements from 499 transects taken at Soviet drifting stations between 1955 and 1991 and derive a simple statistical distribution for snow depth over multi-year ice as a function of only the mean snow depth. We then evaluate this snow depth distribution against snow depth transects that span first-year ice to multiyear ice from the MOSAiC, SHEBA and AMSR-Ice field campaigns. Because the distribution can be generated using only the mean snow depth, it can be used in the downscaling of several existing snow depth products for use in flux modelling and altimetry studies. 

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