Freshwater in the Arctic Ocean 2010–2019

Ocean science, Journal Year: 2021, Volume and Issue: 17(4), P. 1081 - 1102

Published: Aug. 17, 2021

Abstract. The Arctic climate system is rapidly transitioning into a new regime with reduction in the extent of sea ice, enhanced mixing ocean and atmosphere, thus coupling within ocean–ice–atmosphere system; these physical changes are leading to ecosystem Ocean. In this review paper, we assess one critically important aspects regime, variability freshwater, which plays fundamental role by impacting stratification ice formation or melt. Liquid solid freshwater exports also affect global system, notably overturning circulation. We how budgets have changed relative 2000–2010 period. include discussions processes such as poleward atmospheric moisture transport, runoff from Greenland Ice Sheet glaciers, snow on vertical redistribution. Notably, cover has become more seasonal mobile; mass loss increased 2010s (particularly western, northern, southern regions) imported warm, salty Atlantic waters shoaled. During 2000–2010, Oscillation transport in-phase positive trend. This cyclonic circulation pattern forces reduced content Atlantic–Eurasian side Ocean gains Beaufort Gyre. show that trend stabilized 2000s, potentially due an compensation between freshening Gyre rest However, large inter-model spread across reanalyses uncertainty observations used study prevent definitive conclusion about degree compensation.

Language: Английский

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The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017

Journal of Advances in Modeling Earth Systems, Journal Year: 2021, Volume and Issue: 13(5)

Published: April 10, 2021

Abstract A description and assessment of the first release Arctic Subpolar gyre sTate Estimate (ASTE _ R1), a data‐constrained ocean‐sea ice model‐data synthesis, is presented. ASTE R1 has nominal resolution 1/3° spans period 2002–2017. The fit model to an extensive (O(10 9 )) set satellite in situ observations was achieved through adjoint‐based nonlinear least squares optimization. improvement solution compared unconstrained simulation reflected misfit reductions 77% for Argo, 50% sea surface height, 58% Fram Strait mooring, 65% Ice Tethered Profilers, 83% extent. Exact dynamical kinematic consistency key advantage R1, distinguishing state estimate from existing ocean reanalyses. Through strict adherence conservation laws, all sources sinks within can be accounted for, permitting meaningful analysis closed budgets at grid‐scale, such as contributions horizontal vertical convergence tendencies heat salt. thus serves biggest effort undertaken date producing specialized ocean‐ice over 21st century. Transports volume, heat, freshwater are consistent with published observation‐based estimates across important Mediterranean gateways. Interannual variability low frequency trends content well represented Barents Sea, western halocline, east subpolar North Atlantic. Systematic biases remain including warm bias Atlantic Water layer deficient inputs rivers Greenland discharge.

Language: Английский

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Large Mesoscale Eddies in the Western Arctic Ocean From Satellite Altimetry Measurements

Journal of Geophysical Research Oceans, Journal Year: 2021, Volume and Issue: 126(5)

Published: April 16, 2021

Abstract Eddies in the Western Arctic play an important role transporting heat, salt, and biogeochemical tracers across continental shelf within deep basins. However, comprehensive observations of regional temporal variability eddy field characteristics are difficult to obtain remotely due presence sea ice, available situ remain relatively sparse. Nonetheless, with continuing global warming, increasingly large areas Ocean become seasonally ice‐free can be observed remote sensing. Here, we use satellite altimetry data acquired between 1993 2018 over detect signatures hot spots mesoscale eddies, validating their detection method using independent optical infrared observations. The measurements were most frequent from July October, revealing 2000 individual eddies that roughly equally partitioned cyclones anticyclones, radii 20 60 km characteristic orbital velocities about 0.05–0.4 m/s. A maximum number detected October Beaufort Sea November Chukchi Sea. interannual is correlated variations intensity freshwater content Gyre. Using statistics, discuss potential formation mechanisms key regions Amundsen Gulf, area adjacent Mackenzie River mouth, western part Sea,

Language: Английский

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The Cyclonic Mode of Arctic Ocean Circulation

Journal of Physical Oceanography, Journal Year: 2021, Volume and Issue: 51(4), P. 1053 - 1075

Published: Jan. 20, 2021

Abstract Arctic Ocean surface circulation change should not be viewed as the strength of anticyclonic Beaufort Gyre. While Gyre is a dominant feature average circulation, empirical orthogonal function analysis dynamic height (1950–89) and satellite altimetry–derived ocean topography (2004–19) show primary pattern variability in its cyclonic mode dominated by depression sea on Russian side Ocean. Changes after Oscillation (AO) maxima 1989 2007–08 an AO minimum 2010 indicate forced with lag about 1 year. Associated one standard deviation increase starting early 1990s, underwent shift evidenced increased spatial-average vorticity. Under AO, complex also includes export ice near-surface freshwater, changed path Eurasian runoff, freshened Sea, weakened cold halocline layer that insulates from Atlantic water heat, impact compounded Water inflow at depth. The mode’s connection important because major global scale climate index predicted to warming. Given present bias concentration situ measurements Transpolar Drift, coordinated effort made better observe mode.

Language: Английский

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Import of Atlantic Water and sea ice controls the ocean environment in the northern Barents Sea

Ocean science, Journal Year: 2022, Volume and Issue: 18(5), P. 1389 - 1418

Published: Sept. 22, 2022

Abstract. The northern Barents Sea is a cold, seasonally ice-covered Arctic shelf sea region that has experienced major warming and ice loss in recent decades. Here, 2-year observational record from two ocean moorings provides new knowledge about the seasonal hydrographic variability exchange across its margin. combined records of temperature, salinity, currents show advection warmer saltier waters Atlantic origin into north. source these water masses Water boundary current flows along continental slope north Svalbard. Time-varying southward inflow through cross-shelf troughs was main driver cycle temperature at moorings. Inflows were intensified autumn early winter, some cases occurring below cover halocline water. On shorter timescales, subtidal correlated with large-scale meridional atmospheric pressure gradient, suggesting wind-driven modulation inflow. mooring also import lasting impact on upper ocean, where salinity stratification are strongly affected by amount melted area. A fresh layer separated surface warm mid-depth following large imports 2019, whereas diluted found close to during episodes 2018 long ice-free period. Thus, advective surrounding areas both key drivers region.

Language: Английский

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