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1. Introduction In contrast to the rapidly warming Arctic, sea surface temperature (SST) averaged over the Southern Ocean (SO) has exhibited a multidecadal cooling trend from the beginning of the satellite record in 1979 ( Fan et al. 2014 ; Armour and Bitz 2015 ) (although this trend may have reversed since late 2016; Meehl et al. 2019 ). During the same period, there have also been significant changes in the Southern Hemisphere (SH) atmospheric circulation, including a poleward shift and
1. Introduction In contrast to the rapidly warming Arctic, sea surface temperature (SST) averaged over the Southern Ocean (SO) has exhibited a multidecadal cooling trend from the beginning of the satellite record in 1979 ( Fan et al. 2014 ; Armour and Bitz 2015 ) (although this trend may have reversed since late 2016; Meehl et al. 2019 ). During the same period, there have also been significant changes in the Southern Hemisphere (SH) atmospheric circulation, including a poleward shift and
stress. For steady winds, the resulting solution is the Ekman spiral, which has a characteristic exponential amplitude decay and anticyclonic (anticlockwise in the Southern Hemisphere) rotation with increasing depth. Integrating flow over the depth of the Ekman spiral results in a net transport that is 90° to the left of the wind in the Southern Hemisphere. Ekman transport is central to the wind-driven circulation and within the Southern Ocean is significant in the meridional overturning circulation
stress. For steady winds, the resulting solution is the Ekman spiral, which has a characteristic exponential amplitude decay and anticyclonic (anticlockwise in the Southern Hemisphere) rotation with increasing depth. Integrating flow over the depth of the Ekman spiral results in a net transport that is 90° to the left of the wind in the Southern Hemisphere. Ekman transport is central to the wind-driven circulation and within the Southern Ocean is significant in the meridional overturning circulation
1. Introduction The importance of the Southern Ocean in the global circulation and climate is largely attributed to its energetic transient eddy field ( Rintoul and Naveira Garabato 2013 , and references therein). Transient eddies transport tracers horizontally and momentum vertically, flux heat poleward (e.g., Olbers et al. 2004 ), modulate changes in the Antarctic Circumpolar Current (ACC) transport (e.g., Meredith and Hogg 2006 ; Morrison and Hogg 2013 ), and partly compensate the wind
1. Introduction The importance of the Southern Ocean in the global circulation and climate is largely attributed to its energetic transient eddy field ( Rintoul and Naveira Garabato 2013 , and references therein). Transient eddies transport tracers horizontally and momentum vertically, flux heat poleward (e.g., Olbers et al. 2004 ), modulate changes in the Antarctic Circumpolar Current (ACC) transport (e.g., Meredith and Hogg 2006 ; Morrison and Hogg 2013 ), and partly compensate the wind
1. Introduction The ability to represent the oceanic response to changes in mechanical and buoyancy forcings is of fundamental importance for understanding the climatic impact of increasing concentrations of atmospheric greenhouse gases (GHGs). The Southern Ocean is a key player in the earth’s climate for its importance in the global ocean circulation and water mass formation, interbasin connections, and air–sea exchanges of heat, freshwater, and tracer gases. The Antarctic Circumpolar Current
1. Introduction The ability to represent the oceanic response to changes in mechanical and buoyancy forcings is of fundamental importance for understanding the climatic impact of increasing concentrations of atmospheric greenhouse gases (GHGs). The Southern Ocean is a key player in the earth’s climate for its importance in the global ocean circulation and water mass formation, interbasin connections, and air–sea exchanges of heat, freshwater, and tracer gases. The Antarctic Circumpolar Current
1. Introduction Over recent decades, the ocean has absorbed 93% of the additional energy in the climate system arising from global warming ( Levitus et al. 2012 ). Subsurface ocean heat gain has had a beneficial impact thus far through limiting atmospheric warming. However, ocean heat gain also leads to increasingly significant sea level rise, slower ocean carbon uptake, and potentially accelerated melting of the Antarctic ice sheets ( IPCC 2013 ). The Southern Ocean has been recognized as an
1. Introduction Over recent decades, the ocean has absorbed 93% of the additional energy in the climate system arising from global warming ( Levitus et al. 2012 ). Subsurface ocean heat gain has had a beneficial impact thus far through limiting atmospheric warming. However, ocean heat gain also leads to increasingly significant sea level rise, slower ocean carbon uptake, and potentially accelerated melting of the Antarctic ice sheets ( IPCC 2013 ). The Southern Ocean has been recognized as an
they exhibit considerable spatial structure, increasing toward the western margins of ocean basins, where large air–sea contrasts are maintained by the continuous supply of (cold and dry) continental air. In the tropics feedbacks are observed to be weaker than in middle latitudes. Air–sea feedbacks in closed basins and over (western) boundary current regimes are reasonably well documented in the Northern Hemisphere (NH), as well as in the low latitudes of the Southern Hemisphere (SH). In the
they exhibit considerable spatial structure, increasing toward the western margins of ocean basins, where large air–sea contrasts are maintained by the continuous supply of (cold and dry) continental air. In the tropics feedbacks are observed to be weaker than in middle latitudes. Air–sea feedbacks in closed basins and over (western) boundary current regimes are reasonably well documented in the Northern Hemisphere (NH), as well as in the low latitudes of the Southern Hemisphere (SH). In the
2004 ). Despite the presence of sea ice, polar amplification is not generally observed at the surface of the Southern Ocean in twenty-first-century scenarios. In fact, some future climate runs show a statistically significant decrease in temperature in the Ross Sea zone of the Southern Ocean (e.g., Bitz et al. 2006 ). This is not just a phenomenon of future climate change; in the past few decades, surface air temperatures (SATs) in some parts of the Southern Ocean have experienced no significant
2004 ). Despite the presence of sea ice, polar amplification is not generally observed at the surface of the Southern Ocean in twenty-first-century scenarios. In fact, some future climate runs show a statistically significant decrease in temperature in the Ross Sea zone of the Southern Ocean (e.g., Bitz et al. 2006 ). This is not just a phenomenon of future climate change; in the past few decades, surface air temperatures (SATs) in some parts of the Southern Ocean have experienced no significant
1. Introduction The meridional overturning circulation (MOC) is a global-scale circulation that, due to its important role in the redistribution of heat, salt, and biogeochemical tracers from warmer to colder latitudes and the subduction of atmospheric CO 2 , has a large influence on the climate system ( Talley et al. 2003 ; Marshall and Speer 2012 ). In the Southern Ocean, the overturning is related to the rate that deep carbon-rich waters are ventilated at the surface where they can
1. Introduction The meridional overturning circulation (MOC) is a global-scale circulation that, due to its important role in the redistribution of heat, salt, and biogeochemical tracers from warmer to colder latitudes and the subduction of atmospheric CO 2 , has a large influence on the climate system ( Talley et al. 2003 ; Marshall and Speer 2012 ). In the Southern Ocean, the overturning is related to the rate that deep carbon-rich waters are ventilated at the surface where they can
Creation of a Gridded Dataset for the Southern Ocean with a Topographic Constraint Scheme1. Introduction The Southern Ocean is pivotal in the meridional overturning circulation of the global oceans because it connects all major ocean basins (e.g., Schmitz 1996 ). Recently, widespread freshening of water masses, possibly linked to enhanced basal melt of the Antarctic Ice Sheet (e.g., Pritchard et al. 2012 ; Rignot et al. 2013 ), has been reported in the Southern Ocean ( Schmidtko et al. 2014 ; Aoki et al. 2013 ; Boyer et al. 2005 ). Furthermore, there has been clear evidence of
1. Introduction The Southern Ocean is pivotal in the meridional overturning circulation of the global oceans because it connects all major ocean basins (e.g., Schmitz 1996 ). Recently, widespread freshening of water masses, possibly linked to enhanced basal melt of the Antarctic Ice Sheet (e.g., Pritchard et al. 2012 ; Rignot et al. 2013 ), has been reported in the Southern Ocean ( Schmidtko et al. 2014 ; Aoki et al. 2013 ; Boyer et al. 2005 ). Furthermore, there has been clear evidence of
1. Introduction The Antarctic Circumpolar Current (ACC) is the world’s strongest ocean current with a zonal transport of 137 ± 7 Sverdrups (Sv; 1 Sv ≡ 10 6 m 3 s −1 ; Meredith et al. 2011 ) and is the primary conduit between the major ocean basins. Strong westerly winds overlying the ACC are a potential source of eastward momentum for the mean flow, and low-resolution models of the Southern Ocean [such as general circulation models (GCMs) used for climate prediction] suggest that the
1. Introduction The Antarctic Circumpolar Current (ACC) is the world’s strongest ocean current with a zonal transport of 137 ± 7 Sverdrups (Sv; 1 Sv ≡ 10 6 m 3 s −1 ; Meredith et al. 2011 ) and is the primary conduit between the major ocean basins. Strong westerly winds overlying the ACC are a potential source of eastward momentum for the mean flow, and low-resolution models of the Southern Ocean [such as general circulation models (GCMs) used for climate prediction] suggest that the
