Improved Analytical Theory of Rossby Wave Driven Eulerian and Lagrangian Mean Flows Along Non-Zonal Barriers, with Application to the Hawaiian Ridge

摘要

We study the reflection of baroclinic Rossby waves from a non-zonal barrier. In doing so we improve and extend an analytical study by Mysak and Magaard (1983). We add lateral friction to their model and obtain not only a more realistic Eulerian secondary flow, but we also calculate the Stokes drift of the total Rossby wave field. We apply our improved and extended model to the Hawaiian Ridge where the incident wave field is known (magaard, 1983). Compared to the case of vanishing lateral friction, the Eulerian mean flow now shows smaller current speeds and wider current bands. The narrow eastward jet in the immediate neighborhood of the Ridge is now replaced by a much weaker, broader eastward flow. The subsequent western boundary current and eastward countercurrent are now shifted farther away from the Ridge in better agreement with White's (1983) analysis of historical temperature data. The Lagrangian mean flow is stronger than the Eulerian mean flow. Within the first 100 km off the Ridge the two flows are mostly in opposite directions. (Author)