Influence of EBES seamount and Farallon basin on coastal circulation in the Gulf of California, Mexico

Abstract

Hydrographic and current observations were gathered during a 1997 cruise in the southern Gulf of California, off La Paz Bay, to study coastal circulation and the influence of El Bajo de Espíritu Santo (EBES) seamount on the local flow. We detect an unusual presence of equatorial surface water related to the El Niño event of 1997-1998. In Farallón basin we describe a 120 km diameter near-surface cyclonic eddy from ADCP current measurements, geostrophic calculations and satellite imagery. Flow measurements show an intense (> 0.5 m s-1) and narrow (25 km) coastal jet flowing north towards the interior of the Gulf along the Baja California coast. A Lagrangian analysis of the flow field over the seamount shows the coastal jet and the convergence of the impinging flows where bathymetry is important.

Keywords

• Seamount
• coastal circulation
• cyclonic eddy
• Gulf of California