Possible oceanic feedback in the extratropics in relation to the North Atlantic SST tripole

Takashi Mochizuki, Toshiyuki Awaji, Nozomi Sugiura

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We analyze the results of 4-dimensional variational data assimilation experiments using a coupled general circulation model and identify signals from a possible extratropical oceanic feedback relating to the North Atlantic Sea Surface Temperature (SST) tripole. Examination of the optimized control variables (coupling parameters) and the resultant climate fields reveals that the model errors in the North Atlantic climate variations are very sensitive to the intensity of the extratropical air-sea thermal coupling. This results in the enhancement of the atmospheric responses to SST changes particularly around 40°N, 50°W, when the model errors are most effectively corrected. Since an adjoint approach enables us to detect the sensitivity to fluctuations in the model variables, our results suggest that this oceanic thermal feedback in the extratropics is a key physical process influencing the North Atlantic Oscillation and the associated North Atlantic SST tripole.

Original languageEnglish
Article numberL05710
JournalGeophysical Research Letters
Volume36
Issue number5
DOIs
Publication statusPublished - Mar 16 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

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