Joint Seminar: A regime diagram for ocean geostrophic turbulence

A two-dimensional regime diagram for geostrophic turbulence in the ocean is constructed by plotting observation-based estimates of the nondimensional eddy radius and unsuppressed mixing length against a nonlinearity parameter equal to the ratio of the root-mean square eddy velocity and baroclinic Rossby phase speed. For weak nonlinearity, as found in the tropics, the mixing length mostly corresponds to the stability threshold for baroclinic instability whereas the eddy radius corresponds to the Rhines scale; it is suggested that this mismatch is indicative of the inverse energy cascade that occurs at low latitudes in the ocean and the zonal elongation of eddies. At larger values of nonlinearity, as found at mid- and high-latitudes, the eddy length scales are much shorter than the stability threshold, within a factor of 2.5 of the Rossby deformation radius.

Date

04.09.2015

Time

14:15 h

Place

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

Speaker

Andreas Klocker, Institute for Marine and Antarctic Studies University of Tasmania

Organizers

Carsten Eden

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