Journal of the Marine Biological Association of the UK



Research Article

Annual westward propagating anomalies near 26°N and eddy generation south of the Canary Islands: remote sensing (altimeter/SeaWiFS) and in situ measurement


Robin  Pingree a1a2c1 and Carlos  Garcia-Soto a3
a1 Institute of Marine Studies, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK
a2 The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
a3 Centro Oceanográfíco de Santander, Instituto Español de Oceanografía (IEO), Ministerio de Ciencia y Tecnología (MCyT), Promontorio de San Martin s/n, 39004 Santander, Spain

Article author query
pingree r   [PubMed][Google Scholar] 
garcia-soto c   [PubMed][Google Scholar] 

Abstract

Seasonal changes in altimeter data are derived for the North Atlantic Ocean. Altimeter data are then used to examine annually propagating structure along 26°N. By averaging the altimeter data into monthly values or by Fourier analysis, a positive anomaly can be followed from 17°W to [similar]50°W along [similar]26°N. The methods give a westward travel speed of 1° of longitude a month and a half-life of one year for the average decaying structure. At [similar]50°W 26°N, the average structure is about 2·8 years old with an elevation signal of [similar]1 cm, having travelled [similar]3300 km westward. The mean positive anomaly results from the formation of anticyclonic eddies which are generally formed annually south of the Canary Islands by late summer and which then travel westward near 26°N. Individual eddy structure along 26°N is examined and related to in situ measurements and anomalies in the annual seasonal concentration cycle of SeaWiFS chlorophyll-a.

(Received November 3 2003)
(Accepted August 27 2004)


Correspondence:
c1 e-mail: rdpi@mba.ac.uk