On the Linkage between Antarctic Surface Water Stratification and Global Deep-Water Temperature

Visbeck, Martin

doi:10.1175/2011jcli3642.1

Cited by 9 publications

(5 citation statements)

References 42 publications

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“…This entrainment of heat is critical in a balance of controlling the amount of sea-ice that is locally produced, and modulates the probability of appearance of open ocean polynya [Gordon, 1991;Gordon et al, 2007]. Our results show an entrainment of 20-60 W m 22 at the shelf break in winter (Figure 10), in good agreement with earlier estimates of 41 W m 22 [e.g., Gordon and Huber, 1990;Keeling and Visbeck, 2011]. This entrainment provides an efficient pathway for exchange of heat, freshwater, as well as air-sea gas exchange (e.g., carbon dioxide, oxygen) between the deep ocean and the atmosphere [Gordon, 1991;Sigman and Boyle, 2000], which makes the Antarctic sea-ice sector surface layer and its associated weak stability a critical feature of the global climate system [Sigman et al, 2010].…”

Section: 1002/2016jc011970supporting

confidence: 91%

The ocean mixed layer under Southern Ocean sea-ice: Seasonal cycle and forcing

Pellichero

Sallée

Schmidtko

et al. 2017

J. Geophys. Res. Oceans

106

123

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The oceanic mixed layer is the gateway for the exchanges between the atmosphere and the ocean; in this layer, all hydrographic ocean properties are set for months to millennia. A vast area of the Southern Ocean is seasonally capped by sea‐ice, which alters the characteristics of the ocean mixed layer. The interaction between the ocean mixed layer and sea‐ice plays a key role for water mass transformation, the carbon cycle, sea‐ice dynamics, and ultimately for the climate as a whole. However, the structure and characteristics of the under‐ice mixed layer are poorly understood due to the sparseness of in situ observations and measurements. In this study, we combine distinct sources of observations to overcome this lack in our understanding of the polar regions. Working with elephant seal‐derived, ship‐based, and Argo float observations, we describe the seasonal cycle of the ocean mixed‐layer characteristics and stability of the ocean mixed layer over the Southern Ocean and specifically under sea‐ice. Mixed‐layer heat and freshwater budgets are used to investigate the main forcing mechanisms of the mixed‐layer seasonal cycle. The seasonal variability of sea surface salinity and temperature are primarily driven by surface processes, dominated by sea‐ice freshwater flux for the salt budget and by air‐sea flux for the heat budget. Ekman advection, vertical diffusivity, and vertical entrainment play only secondary roles. Our results suggest that changes in regional sea‐ice distribution and annual duration, as currently observed, widely affect the buoyancy budget of the underlying mixed layer, and impact large‐scale water mass formation and transformation with far reaching consequences for ocean ventilation.

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Section: 1002/2016jc011970supporting

confidence: 91%

The ocean mixed layer under Southern Ocean sea-ice: Seasonal cycle and forcing

Pellichero

Sallée

Schmidtko

et al. 2017

J. Geophys. Res. Oceans

106

123

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“…4) leading to a small thermosteric sea level rise. This behaviour is in good agreement in the processes described by Stouffer et al (2007), with increased incidences of deep convection resulting from the warmer deep waters similar to that found by Keeling and Visbeck (2011). With very little glacial melt in the Weddell Sea region, the stratification there is relatively weak (0.2 psu) until the last decade of the simulation.…”

Section: Time Mean Dsl Changessupporting

confidence: 86%

The land-ice contribution to 21st-century dynamic sea level rise

et al. 2014

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Abstract. Climate change has the potential to influence global mean sea level through a number of processes including (but not limited to) thermal expansion of the oceans and enhanced land ice melt. In addition to their contribution to global mean sea level change, these two processes (among others) lead to local departures from the global mean sea level change, through a number of mechanisms including the effect on spatial variations in the change of water density and transport, usually termed dynamic sea level changes.In this study, we focus on the component of dynamic sea level change that might be given by additional freshwater inflow to the ocean under scenarios of 21st-century land-based ice melt. We present regional patterns of dynamic sea level change given by a global-coupled atmosphere-ocean climate model forced by spatially and temporally varying projected ice-melt fluxes from three sources: the Antarctic ice sheet, the Greenland Ice Sheet and small glaciers and ice caps. The largest ice melt flux we consider is equivalent to almost 0.7 m of global mean sea level rise over the 21st century. The temporal evolution of the dynamic sea level changes, in the presence of considerable variations in the ice melt flux, is also analysed.We find that the dynamic sea level change associated with the ice melt is small, with the largest changes occurring in the North Atlantic amounting to 3 cm above the global mean rise. Furthermore, the dynamic sea level change associated with the ice melt is similar regardless of whether the simulated ice fluxes are applied to a simulation with fixed CO 2 or under a business-as-usual greenhouse gas warming scenario of increasing CO 2 .

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Section: Time Mean Dsl Changessupporting

confidence: 86%

The land-ice contribution to 21st century dynamic sea-level rise

Howard¹,

Ridley²,

Pardaens³

et al. 2014

Preprint

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Abstract. Climate change has the potential to locally influence mean sea level through a number of processes including (but not limited to) thermal expansion of the oceans and enhanced land ice melt. These lead to departures from the global mean sea level change, due to spatial variations in the change of water density and transport, which are termed dynamic sea level changes. In this study we present regional patterns of sea-level change projected by a global coupled atmosphere–ocean climate model forced by projected ice-melt fluxes from three sources: the Antarctic ice sheet, the Greenland ice sheet and small glaciers and ice caps. The largest ice melt flux we consider is equivalent to almost 0.7 m of global sea level rise over the 21st century. Since the ice melt is not constant, the evolution of the dynamic sea level changes is analysed. We find that the dynamic sea level change associated with the ice melt is small, with the largest changes, occurring in the North Atlantic, contributing of order 3 cm above the global mean rise. Furthermore, the dynamic sea level change associated with the ice melt is similar regardless of whether the simulated ice fluxes are applied to a simulation with fixed or changing atmospheric CO2.

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On the Linkage between Antarctic Surface Water Stratification and Global Deep-Water Temperature

Abstract: -3 -

Cited by 9 publications

References 42 publications

The ocean mixed layer under Southern Ocean sea-ice: Seasonal cycle and forcing

The ocean mixed layer under Southern Ocean sea-ice: Seasonal cycle and forcing

The land-ice contribution to 21st-century dynamic sea level rise

The land-ice contribution to 21st century dynamic sea-level rise

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