The High-Latitude Southern Ocean: An Ongoing Challenge for Climate Models

In contrast to the Arctic Ocean, the high-latitude Southern Ocean (SO) is generally characterized by weak stratification. This makes the SO sea-ice cover, and thus the surface buoyancy fluxes, highly dependent on the ocean conditions. Dense water is predominantly formed along the Antarctic coastline, the rate of formation being strongly affected by the coastal winds, and thus local orography. The associated ocean mixing processes are commonly termed open-ocean and near boundary convection, respectively. Prerequisite for a proper simulation of these processes are at least an overall realistic water-mass distribution and detailed coastal wind fields, both of which are generally not captured in current climate models. The discrepancy in recent SO sea-ice trends between observations (positive) and climate models (negative) is likely linked to this failure. Another crucial variable determining the sea-ice trends is the freshwater flux. This talk will elaborate on these issues, and discuss how this dilemma can possibly be solved using high-frequency variability of temperature and salinity, as well as sea-ice thickness as control variables.




15:15 h


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


Achim Stoessel, Texas A&M University


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