Seasonal gyres in the northern Gulf of California

Authors
Citation
E. Beier et P. Ripa, Seasonal gyres in the northern Gulf of California, J PHYS OCEA, 29(2), 1999, pp. 305-311
Citations number
10
Categorie Soggetti
Aquatic Sciences","Earth Sciences
Journal title
JOURNAL OF PHYSICAL OCEANOGRAPHY
ISSN journal
00223670 → ACNP
Volume
29
Issue
2
Year of publication
1999
Pages
305 - 311
Database
ISI
SICI code
0022-3670(199902)29:2<305:SGITNG>2.0.ZU;2-7
Abstract
The circulation pattern in the northern Gulf of California, based on drifti ng buoys and hydrographic observations, can be explained using the results of a linear two-layer primitive equations model forced, at the annual frequ ency, by the Pacific Ocean;wind stress, and heat Aux through the surface. T he modeled surface circulation consists of a cyclonic gyre from June to Oct ober and an anticyclonic gyre from December to April, both located in the c entral region of the northern Gulf of California, which includes Angel de l a Guarda Island. The maximum intensities of the gyres occur in August and F ebruary, respectively, with values of surface velocities of 65 cm s(-1) (in agreement with the observations) and very low opposite velocities in the b ottom layers. May and November are transition months in which both gyres ca n be observed. Finally, in June/July or December/January the growing gyre i s still connected with the rest of the Gulf of California, through the narr ows between Tiburon Island, San Esteban Island, and the Baja California coa st, whereas from August through October and from February through April the respective gyre is isolated. The vertical structure of the model results i ndicates a mainly baroclinic signal both in the southern and central region s of the Gulf of California. In the northern gulf, however, the velocities in the annual signal are a combination of barotropic and baroclinic movemen ts, with similar intensities, coupled by topography effects. Thus, only par t of the dynamics is associated to great movements of the interface, which shows maximum values of 40 m.