HR: 11:20h
AN: OS12B-05    [Abstracts]
TI: Assessing the Hydraulic Criticality of Deep Ocean Overflows
AU: * Pratt, L J
EM: lpratt@whoi.edu
AF: Woods Hole Oceanographic Inst., Mail Stop 21, 360 Woods Hole Rd., Woods Hole, MA 02543 United States
AU: Helfrich, K R
EM: khelfrich@whoi.edu
AF: Woods Hole Oceanographic Inst., Mail Stop 21, 360 Woods Hole Rd., Woods Hole, MA 02543 United States
AB: Two methods for assessing the hydraulic criticality of a modelled or observed deep overflow are discussed. The methods should be of use in determining the position of the control section, which is needed to establish the transport relation helpful for long-term monitoring from upstream. Both approaches are based on a multiple streamtube idealization in which the observed flow at a particular section is divided up into subsections (streamtubes). There are no restrictions on the bottom topography or potential vorticity distribution. The first criteria involves evauation of a generalized Jacobian condition based on the conservation laws for each streamtube; the second involves direct calculation of the long-wave phase speeds. We also comment on the significance of the local Froude number F of the flow and argue that F must pass through unity across a section of hydraulic control. These criteria are applied to some numerically modelled flows and are used in the companion presentation (Girton, et al.) to evaluate the hydraulic criticality of the Faroe Bank Channel.
DE: 4512 Currents
DE: 4544 Internal and inertial waves
DE: 3220 Nonlinear dynamics
DE: 1635 Oceans (4203)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting