# Controlling High-Latitude Southern Ocean Convection in Climate Models

Author(s) Stössel, Achim, Notz, Dirk, Haumann, F. Alexander, Haak, Helmuth, Jungclaus, Johann H., Mikolajewicz, Uwe
Publication Type Journal Items, Publication Status: Published
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## Detailed Information

Title Controlling High-Latitude Southern Ocean Convection in Climate Models
Author(s) Stössel, Achim
Notz, Dirk
Haumann, F. Alexander
Haak, Helmuth
Jungclaus, Johann H.
Mikolajewicz, Uwe
Journal or Series Title Ocean Modelling
Volume Number 86
Start Page 58
End Page 75
ISSN 1463-5003
Publisher Elsevier Science
Publication Place Oxford
Publication Date 2015
Keyword(s) Climate models
Convection
High-latitude Southern Ocean
Sea ice
Surface buoyancy fluxes
Abstract Earth System Models (ESMs) generally suffer from a poor simulation of the High-Latitude Southern Ocean (HLSO). Here we aim at a better understanding of the shortcomings by investigating the sensitivity of the HLSO to the external freshwater flux and the horizontal resolution in forced and coupled simulations with the Max-Planck-Institute Ocean Model (MPIOM). Forced experiments reveal an immediate reduction of open-ocean convection with additional freshwater input. The latter leads to a remarkably realistic simulation of the distinct water-mass structure in the central Weddell Sea featuring a temperature maximum of +0.5. °C at 250. m depth. Similar, but more modest improvements occur over a time span of 40. years after switching from a forced to a coupled simulation with an eddy-resolving version of MPIOM. The switch is accompanied with pronounced changes of the external freshwater flux and the wind field, as well as a more realistic heat flux due to coupling. Similar to the forced freshwater-flux experiments, a heat reservoir develops at depth, which in turn decreases the vertically integrated density of the HLSO and reduces the Antarctic Circumpolar Current to rather realistic values. Coupling with a higher resolution version of the atmosphere model (ECHAM6) yields distinct improvements of the HLSO water-mass structure and sea-ice cover. While the coupled simulations reveal a realistic amount of Antarctic runoff, its distribution appears too concentrated along the coast. Spreading the runoff over a wider region, as suggested in earlier studies to mimic the effect of freshwater transport through icebergs, also leads to noticeable improvements of the HLSO water-mass properties, predominantly along the coast. This suggests that the spread of the runoff improves the representation of Antarctic Bottom Water formation through enhanced near-boundary convection rather than weakened open-ocean convection.
DOI 10.1016/j.ocemod.2014.11.008
Document Type Article
Publication Status Published
Language English
Assigned Organisational Unit(s) 03731
Organisational Unit(s)
NEBIS System Number 004079756
Source Database ID FORM-1420544728
SCOPUS-84920996552
WOS-000349695700004
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@article{Stssl2015,
author = "St{\"{o}}ssel, Achim and Notz, Dirk and Haumann, F. Alexander and Haak, Helmuth and Jungclaus, Johann H. and Mikolajewicz, Uwe",
title = "{C}ontrolling {H}igh-{L}atitude {S}outhern {O}cean {C}onvection in {C}limate {M}odels",
journal = "Ocean Modelling",
year = 2015,
volume = "86",
pages = "58--75",
}


E-Citations record created: Tue, 06 Jan 2015, 11:45:37 CET