Trends in latent and sensible heat fluxes over the oceans surrounding the Arctic Ocean

Abstract Analyzing a multi-model ensemble of coupled climate model simulations forced with Arctic sea-ice loss using a two-parameter pattern-scaling technique to remove the cross-coupling between low- and high-latitude responses, the sensitivity to high-latitude sea-ice loss is isolated and contrasted to the sensitivity to low-latitude warming. In spite of some differences in experimental design, the Northern Hemisphere near-surface atmospheric sensitivity to sea-ice loss is found to be robust across models in the cold season; however, a larger inter-model spread is found at the surface in boreal summer, and in the free tropospheric circulation. In contrast, the sensitivity to low-latitude warming is most robust in the free troposphere and in the warm season, with more inter-model spread in the surface ocean and surface heat flux over the Northern Hemisphere. The robust signals associated with sea-ice loss include upward turbulent and longwave heat fluxes where sea-ice is lost, warming and freshening of the Arctic ocean, warming of the eastern North Pacific relative to the western North Pacific with upward turbulent heat fluxes in the Kuroshio extension, and salinification of the shallow shelf seas of the Arctic Ocean alongside freshening in the subpolar North Atlantic. In contrast, the robust signals associated with low-latitude warming include intensified ocean warming and upward latent heat fluxes near the western boundary currents, freshening of the Pacific Ocean, salinification of the North Atlantic, and downward sensible and longwave fluxes over the ocean.

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The shallowing surface temperature inversions in the Arctic

Journal of Climate ◽

10.1175/jcli-d-20-0621.1 ◽

2021 ◽

pp. 1-30

Author(s):

Lin Zhang ◽

Minghu Ding ◽

Tingfeng Dou ◽

Yi Huang ◽

Junmei Lv ◽

...

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

21St Century ◽

Barents Sea ◽

Atmospheric Stability ◽

Heat Fluxes ◽

Spatiotemporal Variability ◽

The Arctic ◽

The Arctic Ocean ◽

Temperature Inversions

AbstractTemperature inversion plays an important role in various physical processes by affecting the atmospheric stability, regulating the development of clouds and fog, and controlling the transport of heat and moisture fluxes. In the past few decades, previous studies have analyzed the spatiotemporal variability of Arctic inversions, but few studies have investigated changes in temperature inversions. In this study, the changes in the depth of Arctic inversions in the mid-21st century are projected based on a 30-member ensemble from the Community Earth System Model Large Ensemble (CESM-LE) project. The ERA-Interim, JRA-55, and NCEP-NCAR reanalyses were employed to verify the model results. The CESM-LE can adequately reproduce the spatial distribution and trends of present-day inversion depth in the Arctic, and the simulation is better in winter. The mean inversion depth in the CESM-LE is slightly underestimated, and the discrepancy is less than 11 hPa within a reasonable range. The model results show that during the mid-21st century, the inversion depth will strongly decrease in autumn and slightly decrease in winter. The shallowing of inversion is most obvious over the Arctic Ocean, and the maximum decrease is over 65 hPa in the Pacific sector in autumn. In contrast, the largest decrease in the inversion depth, which is more than 45 hPa, occurs over the Barents Sea in winter. Moreover, the area where the inversion shallows is consistent with the area where the sea ice is retreating, indicating that the inversion depth over the Arctic Ocean in autumn and winter is likely regulated by the sea ice extent through modulating surface heat fluxes.

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Proxies for heat fluxes to the Arctic Ocean through Fram Strait

Ocean Modelling ◽

10.1016/j.ocemod.2019.02.007 ◽

2019 ◽

Vol 137 ◽

pp. 21-39 ◽

Cited By ~ 1

Author(s):

Pawel Schlichtholz ◽

Jakub Marciniak ◽

Wieslaw Maslowski

Keyword(s):

Arctic Ocean ◽

Heat Fluxes ◽

The Arctic ◽

Fram Strait ◽

The Arctic Ocean

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Arctic mass, freshwater and heat fluxes: methods and modelled seasonal variability

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2014.0169 ◽

2015 ◽

Vol 373 (2052) ◽

pp. 20140169 ◽

Cited By ~ 15

Author(s):

Sheldon Bacon ◽

Yevgeny Aksenov ◽

Stephen Fawcett ◽

Gurvan Madec

Keyword(s):

Numerical Model ◽

Arctic Ocean ◽

Reference Values ◽

Seasonal Variability ◽

Heat Fluxes ◽

The Arctic ◽

Seasonal Cycles ◽

Time Varying ◽

The Arctic Ocean ◽

And Storage

Considering the Arctic Ocean (including sea ice) as a defined volume, we develop equations describing the time-varying fluxes of mass, heat and freshwater (FW) into, and storage of those quantities within, that volume. The seasonal cycles of fluxes and storage of mass, heat and FW are quantified and illustrated using output from a numerical model. The meanings of ‘reference values’ and FW fluxes are discussed, and the potential for error through the use of arbitrary reference values is examined.

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The impact of heterogeneous surface temperatures on the 2-m air temperature over the Arctic Ocean under clear skies in spring

The Cryosphere ◽

10.5194/tc-7-153-2013 ◽

2013 ◽

Vol 7 (1) ◽

pp. 153-166 ◽

Cited By ~ 13

Author(s):

A. Tetzlaff ◽

L. Kaleschke ◽

C. Lüpkes ◽

F. Ament ◽

T. Vihma

Keyword(s):

Air Temperature ◽

Heat Fluxes ◽

The Arctic ◽

Sensible Heat ◽

Wind Fields ◽

Ice Surface ◽

Surface Temperatures ◽

Air Temperatures ◽

Ice Concentration ◽

The Arctic Ocean

Abstract. The influence of spatial surface temperature changes over the Arctic Ocean on the 2-m air temperature variability is estimated using backward trajectories based on ERA-Interim and JRA25 wind fields. They are initiated at Alert, Barrow and at the Tara drifting station. Three different methods are used. The first one compares mean ice surface temperatures along the trajectories to the observed 2-m air temperatures at the stations. The second one correlates the observed temperatures to air temperatures obtained using a simple Lagrangian box model that only includes the effect of sensible heat fluxes. For the third method, mean sensible heat fluxes from the model are correlated with the difference of the air temperatures at the model starting point and the observed temperatures at the stations. The calculations are based on MODIS ice surface temperatures and four different sets of ice concentration derived from SSM/I (Special Sensor Microwave Imager) and AMSR-E (Advanced Microwave Scanning Radiometer for EOS) data. Under nearly cloud-free conditions, up to 90% of the 2-m air temperature variance can be explained for Alert, and 70% for Barrow, using these methods. The differences are attributed to the different ice conditions, which are characterized by high ice concentration around Alert and lower ice concentration near Barrow. These results are robust for the different sets of reanalyses and ice concentration data. Trajectories based on 10-m wind fields from both reanalyses show large spatial differences in the Central Arctic, leading to differences in the correlations between modeled and observed 2-m air temperatures. They are most pronounced at Tara, where explained variances amount to 70% using JRA and 80% using ERA. The results also suggest that near-surface temperatures at a given site are influenced by the variability of surface temperatures in a domain of about 200 km radius around the site.

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The effect of rotation on double diffusive convection: perspectives from linear stability analysis

Journal of Physical Oceanography ◽

10.1175/jpo-d-21-0060.1 ◽

2021 ◽

Author(s):

Yu Liang ◽

Jeffrey R. Carpenter ◽

Mary-Louise Timmermans

Keyword(s):

Stability Analysis ◽

Rayleigh Number ◽

Arctic Ocean ◽

Linear Stability ◽

Linear Stability Analysis ◽

Critical Rayleigh Number ◽

Heat Fluxes ◽

The Arctic ◽

Diffusive Convection ◽

The Arctic Ocean

AbstractDiffusive convection can occur when two constituents of a stratified fluid have opposing effects on its stratification and different molecular diffusivities. This form of convection arises for the particular temperature and salinity stratification in the Arctic Ocean and is relevant to heat fluxes. Previous studies have suggested that planetary rotation may influence diffusive-convective heat fluxes, although the precise physical mechanisms and regime of rotational influence are not well understood. A linear stability analysis of a temperature and salinity interface bounded by two mixed layers is performed here to understand the stability properties of a diffusive-convective system, and in particular the transition from non-rotating to rotationally-controlled heat transfer. Rotation is shown to stabilize diffusive convection by increasing the critical Rayleigh number to initiate instability. In the rotationally-controlled regime, a −4/3 power law is found between the critical Rayleigh number and the Ekman number, similar to the scaling for rotating thermal convection. The transition from non-rotating to rotationally-controlled convection, and associated drop in heat fluxes, is predicted to occur when the thermal interfacial thickness exceeds about 4 times the Ekman layer thickness. A vorticity budget analysis indicates how baroclinic vorticity production is counteracted by the tilting of planetary vorticity by vertical shear, which accounts for the stabilization effect of rotation. Finally, direct numerical simulations yield generally good agreement with the linear stability analysis. This study, therefore, provides a theoretical framework for classifying regimes of rotationally-controlled diffusive-convective heat fluxes, such as may arise in some regions of the Arctic Ocean.

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Atlantic- and Arctic Water transport across the Yermak Plateau

10.5194/egusphere-egu2020-11409 ◽

2020 ◽

Author(s):

Frank Nilsen ◽

Eli Anne Ersdal ◽

Ragnheid Skogseth

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Ocean Circulation ◽

Heat Fluxes ◽

The Arctic ◽

Ocean Current ◽

Bottom Current ◽

The Arctic Ocean ◽

Yermak Plateau

The pathway by which Atlantic Water ultimately inflows to the Arctic Ocean via the Yermak Plateau are of great interest for improving the current understanding of the evolving state of the European Arctic. The Arctic branches of the West Spitsbergen Current (WSC), i.e. the Svalbard Branch (SB), the Yermak Pass Branch (YPB) and the Yermak Branch (YB), are the primary routes through which warm AW enters the Arctic Ocean (AO). These branches either flow around (YB) or passes (SB, YPB) over the Yermak Plateau, the Arctic Sill, which is a topographic obstacle for warm water intrusion to the Arctic and possible melting of sea ice. In addition, The Spitsbergen Polar Current (SPC), carrying fresh costal and Arctic type water from the Barents Sea has to cross the Yermak Platea along the northwestern corner of the Spitsbergen coastline. In order to reveal the dynamics across the YP and the roles of the different AW branches in heat flux variability across this arctic sill, a set of in situ ocean data, ocean climatology (UNIS HD), reanalyzed atmospheric data (NORA10) and altimetry data products from Ssalto/Duacs (CMEMS), where synthesized in order to study the seasonal and year-to-year variability in ocean currents across the YP. In situ data from the Remote Sensing of Ocean Circulation and Environmental Mass Changes (REOCIRC) project consist of water time series of temperature, salinity, ocean current and Ocean Bottom Pressure (OBP), which covered the SB and the SPC. Air-ocean interaction mechanisms for controlling volume transport and heat fluxes in the SB and SPC are presented, and further linked to the variability of the other primary AW routes towards the AO. Moreover, surface geostrophic currents from Absolute Dynamic Topography (ADT) are calibrated against the geostrophic bottom current calculated from in situ OBP recorders. Estimates of winter volume- and heat transports across the YP for the time period 1993-2019 are presented, and interannual variability in the SB linked to the WSC and other AW branches are discussed together with consequences for sea ice melting north of Svalbard.

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The impact of heterogeneous surface temperatures on the 2-m air temperature over the Arctic Ocean in spring

The Cryosphere Discussions ◽

10.5194/tcd-6-3011-2012 ◽

2012 ◽

Vol 6 (4) ◽

pp. 3011-3048 ◽

Cited By ~ 1

Author(s):

A. Tetzlaff ◽

L. Kaleschke ◽

C. Lüpkes ◽

F. Ament ◽

T. Vihma

Keyword(s):

Air Temperature ◽

Heat Fluxes ◽

The Arctic ◽

Sensible Heat ◽

Near Surface ◽

Ice Surface ◽

Surface Temperatures ◽

Air Temperatures ◽

Ice Concentration ◽

The Arctic Ocean

Abstract. The influence of spatial surface temperature changes over the Arctic Ocean on the 2-m air temperature variability is estimated using backward trajectories based on ERA-Interim and the JRA25 wind fields. They are initiated at Alert, Barrow and at the Tara drifting station. Three different methods are used. The first one compares mean ice surface temperatures along the trajectories to the observed 2-m air temperatures at the stations. The second one correlates the observed temperatures to air temperatures obtained using a simple Lagrangian box model which only includes the effect of sensible heat fluxes. For the third method, mean sensible heat fluxes from the model are correlated with the difference of the air temperatures at the model starting point and the observed temperatures at the stations. The calculations are based on MODIS ice surface temperatures and four different sets of ice concentration derived from SSM/I and AMSR-E data. Under nearly cloud free conditions, up to 90% of the 2-m air temperature variance can be explained for Alert, and 60% for Barrow using these methods. The differences are attributed to the different ice conditions, which are characterized by high ice concentration around Alert and lower ice concentration near Barrow. These results are robust for the different sets of reanalyses and ice concentration data. Near-surface winds of both reanalyses show a large inconsistency in the Central Arctic, which leads to a large difference in the correlations between modeled and observed 2-m air temperatures at Tara. Explained variances amount to 70% using JRA and only 45% using ERA. The results also suggest that near-surface temperatures at a given site are influenced by the variability of surface temperatures in a domain of about 150 to 350 km radius around the site.

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