On the mechanisms of late 20th century sea-surface temperature trends over the Antarctic Circumpolar Current

Sergey Kravtsov, Igor Kamenkovich, Andrew M. Hogg, John M. Peters

Research output: Contribution to journalArticle

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Abstract

The Antarctic Circumpolar Current (ACC), with its associated three-dimensional circulation, plays an important role in global climate. This study concentrates on surface signatures of recent climate change in the ACC region and on mechanisms that control this change. Examination of climate model simulations shows that they match the observed late 20th century sea-surface temperature (SST) trends averaged over this region quite well, despite underestimating the observed surface-wind increases. Such wind increases, however, are expected to lead to significant cooling of the region, contradicting the observed SST trends. Motivated by recent theories of the ACC response to variable wind and radiative forcing, the authors used two idealized models to assess contributions of various dynamical processes to the SST evolution in the region. In particular, a high-resolution channel model of the ACC responds to increasing winds by net surface ACC warming due to enhanced mesoscale turbulence and associated heat transports in the mixed layer. These fluxes, modeled, in a highly idealized fashion, via increased lateral surface mixing in a coarse-resolution hybrid climate model, substantially offset zonally non-uniform surface cooling due to air-sea flux and Ekman-transport anomalies. These results suggest that the combination of these opposing effects must be accounted for when estimating climate response to any external forcing in the ACC region.

Original languageEnglish (US)
Article numberC11034
JournalJournal of Geophysical Research C: Oceans
Volume116
Issue number11
DOIs
StatePublished - 2011

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circumpolar current
sea surface temperature
trends
climate models
Climate models
Temperature
climate
climate modeling
surface cooling
cooling
Ekman transport
radiative forcing
wind forcing
climate change
Fluxes
Cooling
surface wind
mixed layer
trend
global climate

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Oceanography

Cite this

On the mechanisms of late 20th century sea-surface temperature trends over the Antarctic Circumpolar Current. / Kravtsov, Sergey; Kamenkovich, Igor; Hogg, Andrew M.; Peters, John M.

In: Journal of Geophysical Research C: Oceans, Vol. 116, No. 11, C11034, 2011.

Research output: Contribution to journalArticle

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