Oceanography Seminar

March 3, 3:00pm - 4:00pm
Mānoa Campus, MSB 100 Add to Calendar

Francois Ascani from the Department of Oceanography at the University of Hawaii at Manoa will be giving a seminar entitled

The role of dissipation in wave-induced transport in a basin

Abstract: Waves and eddies are known to contribute to the transport of mass and heat. Particularly relevant to climate is their transport between low and high latitudes. Dynamically, this transport involves the transport across the mean contours of potential vorticity (PV) that are mostly found parallel to latitudinal circles. At depth, below the direct effect of the wind, the only way for parcel to cross PV contours and change their PV is via dissipation (of momentum and/or density). This link between transport and dissipation has been recognized for a long time but has never been shown explicitly.

Here, using the simple configuration of a circulation in basin driven by a periodic wave field, dissipation modeled by Laplacian friction, and the tools of the Generalized Lagrangian Mean theory, we show numerically that this relationship holds as expected. We also find that there is an optimal value of the Laplacian coefficient for which dissipation and friction are maximized; this leads to the counter-intuitive result that an increase in the friction coefficient can be associated with an increase in transport.

The limitations and extensions of the analysis will be discussed.


Ticket Information
Free

Event Sponsor
Oceanography, Mānoa Campus

More Information
Ocean, 956-7633, Ocean@soest.hawaii.edu, http://www.soest.hawaii.edu/oceanography/seminar.html

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