Current Research

Since joining OSU as a post-doc working with Jack Barth, my primary research focus has been understanding the dynamics of upwelling on the Oregon shelf. The Oregon upwelling system is driven by predominantly equatorward winds during May-September, although this forcing is rather intermittent. Specific research questions relate to the pathways of cross-shelf transport, frontal processes, dynamics of the response to varying winds, and the mechanisms by which different water types become interleaved vertically on varying scales.

Several major interdisciplinary projects have recently improved knowledge of the Oregon upwelling system (COAST, NEP GLOBEC). I have been involved with complimentary observations using less traditional techniques, such as dye tracers, a towed minibat CTD, and largely operating from a small vessel (the 54ft R/V Elakha).

OSU's R/V Elakha leaving Depoe Bay, OR.

Dye tracer studies of upwelling circulation

Fluorescent dye tracers provide a vivid means of following the fate of a water parcel as it is transported, distorted and mixed with surrounding water. Such a `Lagrangian' technique is particularly useful to determine secondary circulation, cross-shelf or cross-frontal flow which controls the evolution of the system but tends to be masked by dominant along-shelf or along-front flow.

An August 2001 pilot experiment led to an NSF proposal, funded for 2002-2005, with Jack Barth and Murray Levine at OSU, in collaboration with Jay Austin at Old Dominion University, VA, who is conducting related modeling studies.

Fieldwork:

Highlights: Feb 2004

Publications are in preparation, but for now ...

This material is based upon work supported by the National Science Foundation under Grant No. 0136900. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Other Research

Georges Bank internal tidal dynamics

A Georges Bank GLOBEC SeaSoar cruise on Oceanus looked at internal tidal dynamics and variability on the Northern Flank of Georges Bank. The intermittent presence of a surface slab of intruding Scotian Shelf Water strongly modifies stratification near the Bank edge with consequences for internal tidal dynamics and mixing. More..

Coastal hydraulics

Hydraulics is the study of a flow as it passes through a slowly varying environment. The need to preserve a set of conserved quantities determines how the flow evolves, and this is dependent on the Froude number of the flow (ie whether or not small perturbations are able to propagate upstream). This is all very mathematically satisifying. In coastal hydraulics, an alongshore flow conserves its mass transport and potential vorticity, while adjusting its structure in response to gradual changes in topography. Could hydraulic control limit the transport of an upwelling jet?? More.

Coastal-trapped waves at and above the inertial frequency

At low (subinertial) frequencies, gravity waves cannot freely propagate, so there is a tendency for energy to be trapped around ocean margins as coastal-trapped waves. Above the inertial frequency gravity waves can propagate freely and coastal-trapped waves become increasingly leaky, although the transition is a smooth one. The near- and super-inertial frequency range was the focus of my PhD with Toby Sherwin at the (then) Unit for Coastal and Estuarine Studies, University of Wales. More.