Spring 1998

No seminar this week....

4:30pm, Thursday, Jan. 8, 1998

No seminar this week....

4:30pm, Thursday, Jan. 15, 1998

Large scale circulation in the Bellingshausen and Amundsen Seas as a Variational Inverse of Climatological Data

Dr. Gleb Panteleev

Dalhousie/Memorial
(Recently of Shirshov Institute of Oceanology (Moscow))

4:30pm, Thursday, Jan. 22, 1998

Thermohaline intrusions in the Arctic Ocean: Cross-front intrusion slopes and driving mechanisms

Brian May

Department of Oceanography
Dalhousie University

4:30pm, Thursday, Jan. 29, 1998

Abstract. Recent surveys indicate that thermohaline intrusions are a wide-spread feature of the Arctic Ocean. With the goal of determining the driving mechanism of the intrusions, we analyse CTD profiles collected in a frontal zone north of Svalbard, where warm salty Atlantic water enters the colder fresher Arctic Ocean.

Tracking intrusions from profile to profile, we show that the intrusions slope upward toward the cold fresh side of the front, relative to horizontal surfaces. This cross-front slope is in the sense expected for driving by buoyancy fluxes from the salt-finger form of double diffusion. It is the wrong sense for driving by the diffusive-convection form. Relative to isopycnal surfaces, the cross-front intrusion slope is opposite: downward toward the cold fresh side of the front. Thus, the intrusion slope lies between the slopes of horizontal and isopycnal surfaces, in the ``wedge'' of baroclinic instability. This indicates that baroclinicity is an additional driving mechanism for interleaving.

In summary, the cross-front slopes suggest that the intrusions are driven by salt fingering and baroclinicity; opposed by diffusive convection. Assuming a simple steady-state balance, we estimate that 30% of the driving comes from salt fingering, while the remaining 70% arises from baroclinicity.

Velocity and transport of the labrador Current determined from altimeter, density, and wind data

Guoqi Han

Coastal Ocean Science, DFO
Bedford Institute of Oceanography

4:30pm, Thursday, Feb. 5, 1998

Internal Wave Mixing Around a Shallow Seamount

Todd Mudge

Department of Oceanography, Dalhousie University

4:30pm, Thursday, Feb. 12, 1998

Thermocline and Circulation Modelling of Conception Bay Newfoundland

Fraser Davidson

Physics and Physical Oceanography
Memorial University of Newfoundland

4:30pm, Thursday, Feb. 19, 1998

Abstract. We apply an eddy resolving numerical C-grid circulation model CANDIE (based on the DieCAST model) to the eastern Newfoundland Shelf. Model resolution is 2kms in the horizontal and 20 m in the vertical. The domain size is 200km by 200km in the horizontal and 400m deep and includes two bays (Trinity and Conception Bays). Model forcing includes topography, time-dependent wind, surface heating and salinity inflow by the Labrador Current. We will discuss the forcing terms in the model as well as the open boundary conditions. Model output will be compared with observations from the region for 1988-1994. The nearshore thermocline displacement will be explored using linear and non-linear version of the model. Retention times for particles and water mass in the bays will be determined for applications of biological interest.

The cross-shore variability of infragravity waves in the nearshore

Tom Lippmann

Center for Coastal Studies
Scripps Institute of Oceanography

4:30pm, Thursday, Feb. 26, 1998

No Seminar This Week

Thursday, Mar. 5, 1998

Boundary layers and circulation in rotating stratified fluid; the structure of jets and circuation in small ocean basins

Jack Whitehead

Woods Hole Oceanographic Institution

4:30pm, Thursday, Mar. 12, 1998

No Seminar This Week

Thursday, Mar. 19, 1998

No Seminar This Week

Thursday, Mar. 26, 1998

No Seminar This Week

Thursday, April 2, 1998

A caustic and critical analysis of gravity-wave interactions

Len Sonmor

Department of Oceanography,
Dalhousie University

4:30pm, Thursday, April 9, 1998

The Dynamics of Plankton Models with Nutrient Recycling

Shigui Ruan

Dept. of Mathematics, Statistics and Computing Science
Dalhousie University

4:30pm, Thursday, April 16, 1998

Abstract: In this talk, we will discuss phytoplankton-nutrient models with both instantaneous and delayed nutrient recycling. Dynamical system methods will be used to study the qualitative properties of these models.

No Seminar This Week

Thursday, April 23, 1998

Length scales of nearshore suspended sediment plumes

Diane Foster

Department of Oceanography, Dalhousie University

4:30pm, Thursday, April 30, 1998

Larval fish assemblages on the Scotian Shelf: is spatial distribution a function of water mass characteristics or surface circulation patterns
C. Reiss, C. T. Taggart, G. Panteleev, B. deYoung

Christian Reiss

Department of Oceanography
Dalhousie University

4:30pm, Thursday, May 7, 1998

Some authors hypothesize that the distribution of ichthyoplankton (several species) on the Scotian Shelf and elsewhere reflect retention associated with marine banks and gyre-like features delineated by density fronts. I will describe results from a field study on the Scotian shelf in November 1997 that examined both the broad-scale and mesoscale distribution of several larval fish species in relation to both water-mass structure and the density driven currents. The density driven surface currents during the sampling period were inferred using the dynamic height method as described by Sheng and Thompson (1995). Two larval assemblages representing demersal (esp. herring and capelin) and pelagic (esp. cod and hake) spawning strategies were observed during the cruise. The pelagic assemblage (cod and hake) was associated with a water mass on the northern flank of Western Bank, reflecting a single spawning location. Herring were found in different water masses, representing multiple spawning populations. The spatial distribution, size and abundance of fish larvae appears to be most easily explained by regions advection and retention as described by the current pattern. There was no evidence for retention of species (e. g. herring) that spawn on the southern edge of Western Bank on the Shelf-Slope. On the northern side of Western Bank a region of relatively unorganized but counter-clockwise flow may be responsible for maintaining larvae (all species) in the area of the Cow pen and the Northern spur (Eastern Emerald Basin).

Recent findings of boundary layer dynamics and sediment transport processes on the Scotian Shelf

Michael Li

Geological Survey of Canada
Bedford Institute of Oceanography

4:30pm, Thursday, May 14, 1998

Special Seminar

A 3D Model of Western Scheldt Estuary for Fine Sediment Transport

Z. Y. Yang

3:00pm, Friday, May 15, 1998

Please note special date and time

Abstract. The Western Scheldt estuary, one of the most intensively used waterways, has been dealing with a lot of changes caused by human activity. For management purposes a 3D model has been developed to calculate the transport of suspended sediment driven by the hydrodynamic conditions within the estuary.

Water movement coupled with salinity transportation is calculated on a grid that is curvilinear in the horizontal direction and which sigma-coordinates in vertical.

The suspended sediment transport model is driven by a database which is generated by the hydrodynamic model. The flocculation process and availability of sediment onbed for erosion are included.

The model structure will be introduced and the first modelling result will be discussed.

No seminar this week

4:30pm, Thursday, May 21, 1998

A Finite Element Model of South Atlantic

Dmitri Netchaev

AWI
Bremerhaven, Germany

4:30pm, Thursday, May 28, 1998

No Seminar This Week

Thursday, June 4, 1998

Title: TBA

Anna Crawford

Department of Physics and Physical Oceanography
Memorial University of Newfoundland

4:30pm, Thursday, June 11, 1998

Acoustic measurements of the velocity field beneath shoaling and breaking waves

J. C. Doering

Hydraulics Research & Testing Facility
Dept. of Civil and Geological Engineering
University of Manitoba

4:30pm, Thursday, July 9, 1998

LSC 4258, Psychology Bldg.