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Temperature flux carried by individual eddies across 47N in the Atlantic Ocean
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Surface geostrophic velocity fields derived from satellite altimetry between January 1993 and April 2014 are used to detect and investigate eddies in the North Atlantic between 40°N–55°N and 60°W–10°W. Focus is on a zonal section along 47°N, roughly at the boundary between the subpolar and the subtropical gyres. Sea surface temperature data are used to quantify the temperature anomalies associated with eddies and the respective surface temperature fluxes related to these eddies. Identified eddy pathways across 47°N are related to the mean background velocity from full-depth ship observations carried out on 11 cruises between 2003 and 2014. The analysis is repeated in two model simulations with 1/4° and 1/12° horizontal resolution, respectively, for the period 2002–2013. The analysis reveals almost 37,000 altimeter-derived eddies with a lifetime longer than 1 week in the area. The highest number of eddies is found along the pathway of the North Atlantic Current, roughly following the 4000 m isobath, and on the Grand Banks of Newfoundland. Time series of temperature fluxes by eddies crossing 47°N reveal that single isolated eddies with large SST signatures contribute ∼25% to the surface temperature flux. Relating the observed eddies to the observed top-to-bottom velocity distribution at 47°N points to the existence of eddy pathways across 47°. The highest-temperature fluxes are linked to the fastest and most pronounced current branches in the western Newfoundland Basin. While there are fewer eddies in both model simulations, the key findings are consistent between the observations and the two model simulations.
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- Date created
- 2017-01-01
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- Article (Published)
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- © 2017. American Geophysical Union. All Rights Reserved.