Posted by Alan Leonardi on December 18, 2001 at 09:25:13:
In Reply to: Re: Leonardi Poster posted by Rick Lumpkin on December 05, 2001 at 11:57:50:
The contradiction in the abstract stems from a typo. The sentences should read:
Topography is important, however, with abyssal currents steering upper ocean transport, resulting in a northward shift of the NEC bifurcation and enhanced NHRC transport north of Hawaii in the upper 1000 m. Interestingly, there is no discernible impact of topography on the surface ocean currents.
The ridge in question is the northward bending of the streamlines from the non-linear, finite depth (black lines) experiment. This feature does indeed stem from the Hawaiian trough east of Hawaii, but more precisely from a localized depression which results in a cyclonic vortex in the lowest layer. Thus, the vertically integrated effect is to first accelerate the flow nothward via the topographically steered abyssal layer flow, and then to steer it southward, producing the ridge. Although this barotropic signal is not evident in the upper layer current field, the upper ocean recognizes the influence of the topographically steered abyssal layer flow in the mean transport ACERAGED OVER THE TOP 1 KM.
In essence, the ridge in the streamlines does not need to correspond to a change in upper layer currents, the change is evident in the overall averaged upper ocean transport. Thus, the discussion is mostly pertinent to WBC transport and not WBC currents, per se.
Hope this helps clear things up a little bit. Thanks for the comment Fred and Rick.