Horizontal and Vertical Structure of Velocity, Potential Vorticity and Energy in the Gulf Stream.
Abstract
A current meter mooring was deployed for one year at the mean position of the Gulf Stream at 68 deg W. Projecting the velocity onto along- and cross-stream components shows that the vertical structure of velocity at the site is described by a baroclinic along-stream and decoupled, barotropic cross-stream component. The well-defined relationship between thermocline temperature and cross-stream component distance allows the use of the former as a horizontal coordinate and enables estimates of mass, momentum and kinetic energy fluxes of the Gulf Stream for four events when it passes over the morning site. Alternatively, an average vertical and horizontal velocity section of the Stream may be constructed, and using that, a potential vorticity section. There is a strong jump from low to high values of thermocline potential vorticity crossing the Stream from south to north. Time-series of vertical velocities have been calculated and their rms sizes are large (0.05 cm/s). The Rossby number below the thermocline is estimated to be > or = 0.1, but in the thermocline it is about 0.3. Diagnostic calculations of the kinetic energy budgets in a quasi-geostrophic eddy-resolving general circulation model suggest that downstream convergence of mean kinetic energy in the Gulf Stream is primarily balanced by mean ageostrophic flow against a pressure gradient. Additional keywords: mathematical models; theses; dissertations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1985
- Accession Number
- ADA154753
Entities
People
- M. M. Hall
Organizations
- Woods Hole Oceanographic Institution