A Numerical Study of Wind Forcing in the Eastern Boundary Current System Off Portugal
Abstract
A high resolution, multi-level, primitive equation ocean model is used to examine the response to wind forcing of an idealized, flat-bottomed oceanic regime on a beta-plane, along the eastern ocean boundary off the west coast of the Iberian Peninsula. Three experiments are conducted to investigate the role of different types of prescribed wind forcing. In experiment 1, a band equatorward winds which are uniform alongshore but contain zonal variability (i. e., large negative wind stress curl near the coast), results in an equatorward coastal surface current nearshore and a poleward surface current offshore. With time, the currents become unstable and anticyclonic warm core eddies develop in the region of negative wind stress curl. In experiment 2, the model is forced with poleward wind stress for 20 days followed by a sudden change to equatorward wind stress. A 1-2 day transition from downwelling and a poleward surface current near the coast to upwelling and an equatorward surface jet occurs. With the time the upwelled isotherms are displaced offshore, the equatorward surface jet widens and gets shallower nearshore, and the poleward undercurrent moves closer to the surface (depth approx. = 120 m at the coast). For experiment 3, a time series of 6-hourly values of the north/south component of the wind, computed from Fleet Numerical Oceanography Center synoptic surface pressure analyses are used to investigate the response of the coastal current system to time dependent wind forcing. (kr)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1989
- Accession Number
- ADA219596
Entities
People
- Carlos N. Lopes Da Costa
Organizations
- Naval Postgraduate School