Evidence of an Eddy-Driven, Intrinsic Interannual Variability in the Southern Ocean.
Abstract
Sea Level Anomalies (SLAs) simulated by the DRAKKAR multi-resolution (2, 1, half- and quarter-degree) hierarchy of global ocean/sea-ice 50-year hindcasts, and derived from altimetry since 1993, are jointly investigated. Simulated SLAs are first collocated onto their observed counterparts in time and space ; all fields are then low-passed filtered to extract observed and simulated large-scale interannual SLA variabilities. The mean state, overall magnitude and structure of the interannual SLA variability are shown to improve with increased model resolution in most areas of the World Ocean, including Southern latitudes; this helps quantify the benefits of model resolution for climate-orented ocean hindcasts/forecasts. Unlike in other regions, the enhanced interannual variability which emerges at eddy-admitting resolution in the Southern Ocean does not project well on the leading EOFs of observed variability, suggesting its possible eddy-driven, non-linear, intrinsic character. Our methods and results, this interpretation and possible implications will be discussed.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMOS12A..02P
- Keywords:
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- 4215 Climate and interannual variability (1616;
- 1635;
- 3305;
- 3309;
- 4513);
- 4490 Turbulence (3379;
- 4568;
- 7863);
- 4520 Eddies and mesoscale processes;
- 4532 General circulation (1218;
- 1222);
- 4556 Sea level: variations and mean (1222;
- 1225;
- 1641)