Vorticity and Internal Waves in the Campeche Canyon, Gulf of Mexico

Abstract

The hydrographic and hydrodynamic structure of the Campeche Canyon (Southern Gulf of Mexico), was studied using oceanographic data obtained from PROMEBIO 3 on board of the R/V Justo Sierra of the UNAM. The sampling was performed during 24 days, in spring 2000. The hydrographic analysis was based on temperature, conductivity and pressure data obtained with a CTD profiler. Current speeds were recorder with a 75 kHz Acoustic Doppler Current Profiler (ADCP). The vertical velocity component (w) and the vertical component of the vorticity (? _z ) were calculated using the horizontal velocity field registered by the ADCP. An objective analysis was applied to obtain homogeneous fields of hydrodynamic parameters such as currents, vorticity, and the Froude and Rossby numbers. Results shows horizontal speeds of the order of 3 × 10^?1 ms^?1; positive vorticity to the Southwest of the study area and negative vorticity toward the Western side of the domain with a magnitude of the order of 10^?6 s^?1. An upward and downward flow pattern was observed over the canyon in agreement with the positive and negative vorticity values, at different deeps. Finally, the Froude number with values below one indicated the existence of internal waves and a hydraulic jump within the Campeche Canyon.