Topographic Eddies

Fig. 4. Froude number regimes for flow over a ridge (black) where the gray lines indicate the position of the water surface, and the black lines the relative flow speed.


This is a article on flow over topography named “Topographic eddies”. It covers the theory behind flow interactions with topography including islands, headlands and capes, sills and seamounts, as well as observational investigations of the same, and their influence on biology.

Encyclopedia of Ocean Sciences

Fig. 1. Examples of varying topography including a sloping ridge, subsurface ridge and headland. Here the H and L indicate regions of high and low pressure, respectively. In the ridge case (lower left), isopycnals are dashed indicating the presence of lee waves. In the headland case (lower right), a lee eddy is shown to the right of the topography. In the sloping ridge (top), a combination of both processes is occurring.

Reproduced from S. J. Warner, P. MacCready (2009). Dissecting the pressure field in tidal flow past a headland: When is form drag “real”? Journal of Physical Oceanography 39, 2971–2984.

Eleanor Frajka-Williams
Eleanor Frajka-Williams
Professor of Ocean Dynamics in a Changing Climate

I am a physical oceanographer who uses ocean observations to investigate ocean dynamics and circulation in a changing climate. I have a particular interest in problems spanning scales (from micro- to large-scale) or spheres (biogeosphere, cryosphere, atmosphere), and in methods that leverage traditional observations with new platforms and satellite data.