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1. Changes in Arctic Ocean Circulation from In Situ and Remotely Sensed Observations: Synergies and Sampling Challenges

   https://doi.org/10.5670/oceanog.2022.111  

   Morison, James; Kwok, Ron; Rigor, Ignatius (January 2022, Oceanography)

   Both in situ and remote sensing observations of Arctic Ocean hydrography and circulation have improved dramatically in recent decades, and combining the two can yield the most complete picture of Arctic Ocean change. Recent results derived from classical hydrography and satellite ocean altimetry illustrate this synergy and also reveal a fundamental in situ sampling challenge. 

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2. Nordic Seas Hydrography in the Context of Arctic and North Atlantic Ocean Dynamics

   https://doi.org/10.1175/JPO-D-20-0071.1  

   Kenigson, J. S.; Timmermans, M.-L. (January 2021, Journal of Physical Oceanography)

   null (Ed.)

   Abstract The hydrography of the Nordic seas, a critical site for deep convective mixing, is controlled by various processes. On one hand, Arctic Ocean exports are thought to freshen the North Atlantic Ocean and the Nordic seas, as in the Great Salinity Anomalies (GSAs) of the 1970s–1990s. On the other hand, the salinity of the Nordic seas covaries with that of the Atlantic inflow across the Greenland–Scotland Ridge, leaving an uncertain role for Arctic Ocean exports. In this study, multidecadal time series (1950–2018) of the Nordic seas hydrography, Subarctic Front (SAF) in the North Atlantic Ocean [separating the water masses of the relatively cool, fresh Subpolar Gyre (SPG) from the warm, saline Subtropical Gyre (STG)], and atmospheric forcing are examined and suggest a unified view. The Nordic seas freshwater content is shown to covary on decadal time scales with the position of the SAF. When the SPG is strong, the SAF shifts eastward of its mean position, increasing the contribution of subpolar relative to subtropical source water to the Atlantic inflow, and vice versa. This suggests that Arctic Ocean fluxes primarily influence the hydrography of the Nordic seas via indirect means (i.e., by freshening the SPG). Case studies of two years with anomalous NAO conditions illustrate how North Atlantic Ocean dynamics relate to the position of the SAF (as indicated by hydrographic properties and stratification changes in the upper water column), and therefore to the properties of the Atlantic inflow and Nordic seas. 

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3. Springtime Export of Arctic Sea Ice Influences Phytoplankton Production in the Greenland Sea

   https://doi.org/10.1029/2019JC015799  

   Mayot, N.; Matrai, P. A.; Arjona, A.; Bélanger, S.; Marchese, C.; Jaegler, T.; Ardyna, M.; Steele, M. (March 2020, Journal of Geophysical Research: Oceans)

   Abstract Climate model projections suggest a substantial decrease of sea ice export into the outflow areas of the Arctic Ocean over the 21st century. Fram Strait, located in the Greenland Sea sector, is the principal gateway for ice export from the Arctic Ocean. The consequences of lower sea ice flux through Fram Strait on ocean dynamics and primary production in the Greenland Sea remain unknown. By using the most recent 16 years (2003–2018) of satellite imagery available and hydrographic in situ observations, the role of exported Arctic sea ice on water column stratification and phytoplankton production in the Greenland Sea is evaluated. Years with high Arctic sea ice flux through Fram Strait resulted in high sea ice concentration in the Greenland Sea, stronger water column stratification, and an earlier spring phytoplankton bloom associated with high primary production levels. Similarly, years with low Fram Strait ice flux were associated with a weak water column stratification and a delayed phytoplankton spring bloom. This work emphasizes that sea ice and phytoplankton production in subarctic “outflow seas” can be strongly influenced by changes occurring in the Arctic Ocean. 

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4. Spatial Complexity in Dissolved Organic Matter and Trace Elements Driven by Hydrography and Freshwater Input Across the Arctic Ocean During 2015 Arctic GEOTRACES Expeditions

   https://doi.org/10.1029/2022JC018917  

   Williford, Tatiana; Amon, Rainer M. W.; Kaiser, Karl; Benner, Ronald; Stedmon, Colin; Bauch, Dorothea; Fitzsimmons, Jessica N.; Gerringa, Loes J. A.; Newton, Robert; Hansell, Dennis A.; et al (November 2022, Journal of Geophysical Research: Oceans)

   Abstract This study traces dissolved organic matter (DOM) in different water masses of the Arctic Ocean and its effect on the distributions of trace elements (TEs; Fe, Cu, Mn, Ni, Zn, Cd) using fluorescent properties of DOM and the terrigenous biomarker lignin. The Nansen, Amundsen, and Makarov Basins were characterized by the influence of Atlantic water and the fluvial discharge of the Siberian Rivers with high concentrations of terrigenous DOM (tDOM). The Canada Basin and the Chukchi Sea were characterized by Pacific water, modified through contact with productive shelf sediments with elevated levels of marine DOM. Within the surface layer of the Beaufort Gyre, meteoric water (river water and precipitation) was characterized by low concentrations of lignin and tDOM fluorescence proxies as DOM is removed during freezing. High‐resolution in situ fluorescence profiles revealed that DOM distribution closely followed isopycnals, indicating the strong influence of sea‐ice formation and melt, which was also reflected in strong correlations between DOM fluorescence and brine contributions. The relationship of DOM and hydrography to TEs showed that terrigenous and marine DOM were likely carriers of dissolved Fe, Ni, Cu from the Eurasian shelves into the central Arctic Ocean. Chukchi shelf sediments were important sources of dCd, dZn, and dNi, as well as marine ligands that bind and carry these TEs offshore within the upper halocline in the Canada Basin. Our data suggest that tDOM components represent stronger ligands relative to marine DOM components, potentially facilitating the long‐range transport of TE to the North Atlantic. 

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5. Emerging Technologies and Approaches for In Situ, Autonomous Observing in the Arctic

   https://doi.org/10.5670/oceanog.2022.127  

   Lee, Craig; DeGrandpre, Michael; Guthrie, John; Hill, Victoria; Kwok, Ron; Morison, James; Cox, Christopher; Singh, Hanumant; Stanton, Timothy; Wilkinson, Jeremy (January 2022, Oceanography)

   Understanding and predicting Arctic change and its impacts on global climate requires broad, sustained observations of the atmosphere-ice-ocean system, yet technological and logistical challenges severely restrict the temporal and spatial scope of observing efforts. Satellite remote sensing provides unprecedented, pan-Arctic measurements of the surface, but complementary in situ observations are required to complete the picture. Over the past few decades, a diverse range of autonomous platforms have been developed to make broad, sustained observations of the ice-free ocean, often with near-real-time data delivery. Though these technologies are well suited to the difficult environmental conditions and remote logistics that complicate Arctic observing, they face a suite of additional challenges, such as limited access to satellite services that make geolocation and communication possible. This paper reviews new platform and sensor developments, adaptations of mature technologies, and approaches for their use, placed within the framework of Arctic Ocean observing needs. 

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