SEARCH CEAFM

Special Seminar

Date: January 11th
Time: 11:00 AM
Location: Maryland Hall 110
Speaker: Brian Arbic
University of Texas
Title: "Global energy dissipation rate of oceanic low-frequency flows by
quadratic bottom drag: Results from observations and 1/32 degree models "

Abstract

In recent years great effort has been expended quantifying the energy
budget of the world ocean. A large motivator in this effort is the
idea that the mixing arising from energy dissipation drives the oceanic
meridional overturning circulation, with important implications for
climate. About 1 TW of power is put into the low-frequency ocean flow by
winds. At least three candidate mechanisms for dissipating this power
have been proposed in the literature. Here we compute quantitative
estimates of the power dissipated by quadratic bottom drag, in bottom
boundary layers. Estimates are derived from both current meter data, with
satellite-altimeter derived surface velocities used to estimate errors due
to the poor sampling of the world ocean by the current meters, and from
high-resolution numerical models, the latter validated by current meter
data. Although our estimates are somewhat uncertain, they all indicate
that a substantial fraction of the wind-power input into low-frequency
flows is dissipated by quadratic bottom drag.