Girton, J. B., University of Washington, Appl, Seattle, USA, girton@apl.washington.edu
Yousoufian, K. S., University of Washington, Seattle, USA, krystay@u.washington.edu

DENMARK STRAIT OVERFLOW EDDIES AS A PROXY FOR THERMOHALINE CIRCULATION VARIABILITY

Cyclonic eddies observed in satellite sea-surface temperature (SST) imagery are an intriguing feature of the Denmark Strait and have been linked to pulsations in the dense overflow from the Nordic Seas. We report on a survey of 3 years of 1-km resolution imagery from the Advanced Very-high Resolution Radiometer database, concentrating on both annual and interannual variability. As expected, annual cycles are apparent in background SST and sea ice extent, but not in eddy size or frequency. Contrary to expectations, we find that a significant amount of cloud-free imagery of at least part of the Denmark Strait is available in all months of all years, leading to the possibility that the eddies could serve as a proxy for overflow variability. Nearly every cloud-free image revealed the presence of eddies, with only small deviations in position from the principal pathway along the Greenland shelf-break and upper slope. The size and shape of the eddies is variable, ranging from simple bumps in the temperature front to fully-developed spirals. This variation appears to be related to pre-existing conditions (including sea ice) as well as to the eddy life cycles as they move through the strait following the overflow. The relationship between these SST eddies and statistics from satellite altimetry and moored current meters is also discussed, along with progress toward automated eddy detection algorithms and monitoring procedures.

Poster presentation

Presentation is given by student: No
Session #:068
Date: 03-03-2008
Time: 17:30 - 19:30

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