Processes controlling upper-ocean heat content in Drake Passage

TitleProcesses controlling upper-ocean heat content in Drake Passage
Publication TypeJournal Article
Year of Publication2013
AuthorsStephenson G.R, Gille ST, Sprintall J
JournalJournal of Geophysical Research-Oceans
Date Published2013/09
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000326230200028
Keywordsannular mode; antarctic circumpolar current; circulation; climate-change; eddies; el-nino; heat; hemisphere; interannual variability; nino-southern-oscillation; sea-ice extent; Southern Ocean; temperature; variability; wind

A 16 year record of expendable bathythermograph transects across Drake Passage is used to examine variability in upper-ocean heat content that is not associated with the annual cycle. Links between upper-ocean heat content and anomalous heat fluxes, winds, two large-scale climate indices, and mesoscale eddies and meanders are examined. Results suggest that interannual variations in surface heat fluxes explain approximate to 5 to 10% of the variance in upper-ocean heat content. Anomalous surface heat fluxes are linked to meridional wind anomalies upstream of Drake Passage, which in turn are linked to forcing by El Nino/Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). ENSO and SAM are correlated with upper-ocean heat content at near-zero lags, and statistically significant correlations occur at longer time lags as well. The impact of mesoscale eddies and meanders on upper-ocean heat content is explored with the use of a tracked eddy database. An empirical relationship is constructed relating upper-ocean heat content anomalies to eddy length scales and amplitudes. Eddies and meanders are estimated to account for more than one third of the nonannual cycle variance in Drake Passage upper-ocean heat content.

Short TitleJ Geophys Res-Oceans
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