Fall 2007

Special Double Seminar

Internal tidal beams and mixing near Monterey Bay, California
Shaun Johnston
2:00 p.m.

and

Internal Waves Across the Pacific
Jennifer McKinnon
3:30 p.m.

***

Physical Oceanography Research Division
Scripps Institution of Oceanography

Thursday, September 20, 2007

The Mean Surface Topography of the North Atlantic: Oceanography and Geodesy Collide

Keith Thompson

Department of Oceanography
Dalhousie University

4:30 p.m., Thursday, September 27, 2007

Baroclinic dynamics and variability of circulation and heat/salt contents in Lunenburg Bay

Li Zhai

Department of Oceanography
Dalhousie University

4:30 p.m., Thursday, October 4, 2007

Statistical downscaling of general circulation models

Lee Titus

Department of Oceanography
Dalhousie University

4:30 p.m., Thursday, October 11, 2007

What's new from the IPCC?
Climate Change 2007 and regional implications

Kyle McKenzie

Environment Canada

4:30 p.m., Thursday, October 18, 2007

Abstract: The Intergovernmental Panel on Climate Change (IPCC) is in the process of releasing its fourth assessment report (AR4), with major sections on our latest knowledge of the physical science basis; impacts, adaptation, and vulnerability; and mitigation options; as well as a synthesis report. With this come revised figures and reduced uncertainty for future temperature, precipitation, and sea level.

How these changes will impact us locally and what might be done to adapt are of interest to the Meteorological Service of Canada's Climate Change Section in Dartmouth. Combining new reports such as the AR4 with regional expertise can help bring in to focus those aspects of climate change that are important locally and help decision makers respond.

A Bio-physical model of the Pan-arctic ocean

Frederic Dupont

Department of Oceanography
Dalhousie University

4:30 p.m., Thursday, October 25, 2007

Abstract: I will present a model of the Pan-Arctic ocean coupled to ice and a biological model. The bioligcal model is a simple 4-compartment NPZD model. The goal is to study the varibility of the primary production in the last 50 years of the 20th century (1950-2000). The model is forced using monthly NCEP/NCAR reanalysis and monthly climatological boundary conditions. The primary climate change forcing comes from a warmer surface atmosphere in early 1980s and for the whole 1990s. An ice biology model was also tested that formally represents the growth and aggregation of phytoplankton into a ice-water `layer', the so-called ice algae. Their importance in the Arctic Ocean stems from the fact that the bottom of the sea-ice is an unique substrate on which the phytoplanktonic cells can experience growth nearly undisturbed by surface mixed layer turbulence. In the model the ice algae contribution to primary production was found to be about 20% to 25% of the pelagic primary production. Overall for the whole Arctic Ocean, reasonable values of primary production were obtained.

Numerical Modelling in the North Atlantic using SPOM and NEMO and Labrador Sea Water Formation

Paul Myers

Department of Earth and Atmospheric Sciences
University of Alberta

4:30 p.m., Thursday, November 1, 2007

Internal wave generation at the shelf break and near-resonant internal wave triads

Kevin Lamb

Department of Applied Mathematics
University of Waterloo

4:30 p.m., Thursday, November 8, 2007

Abstract: Barotropic tides flowing over variably bathymetry is one of the primary mechanisms for internal wave generation in the ocean and is currently a subject of considerable interest. Much of the focus of recent work has been on tidal flow over isolated bathymetric features such as an oceanic ridge. In this talk I will present some recent results from numerical simulations of Internal wave generation at the shelf break. One interesting features of these results is the occurence of near-resonant triad interactions in the wave field. A resonant-triad is a set of three weakly-nonlinearly interacting waves whose wave vectors and frequencies sum to zero. They occur in many physical systems and have played an important role in our understanding of the nonlinear evolution of the internal wave field in the deep ocean. Near-resonant triads are sets of three waves which are detuned: the sum of the wave vectors and/or wave frequencies is no longer exactly zero. While known to occur in other physical systems (e.g., non-linear optics, plasmas) since the early 1960s, their occurence in modal internals waves has attracted little comment in the literature. The history of near-resonant wave triads and their occurence in the internal wave field generated by tidal flow across a shelf break, where they are the dominant form of wave-wave interatctions, will be presented.

Investigation of Circulation, Hydrographic Structure and Connectivity in the Bras d'Or Lakes using a Nested-grid Circulation Model

Bo Yang

Department of Oceanography
Dalhousie University

4:30 p.m., Thursday, November 15, 2007

Abstract: The Bras d'Or Lakes are a land-locked estuary in central Cape Breton Island in Nova Scotia. An oyster parasite known as Haplosporidium nelsoni (MSX) was recently discovered at several localized sites in the Lakes. A nested-grid hydrodynamic modeling system is used to examine the estuary's response to tides, winds and buoyancy forcing associated with freshwater runoff in series of numerical experiments validated with empirical data. The model is also used to reconstruct the three-dimensional (3D) circulation and temperature-salinity distributions in summer 1974, during which currents and hydrographic measurements were made at several locations in the Lakes. Our model results demonstrate that particle exchanges between several small bays over the western Bras d'Or Lakes and main basins of the Lakes are much weaker than those between the main basins of the Lakes, due to the restriction of narrow passage between the small bays and the main basins.

Measuring Pollution in the Troposphere: Two Billion Measurements Later

James Drummond

Department of Physics & Atmospheric Science
Dalhousie University

4:30 p.m., Thursday, November 22, 2007

Abstract: The Canadian Measurements Of Pollution In The Troposphere (MOPITT) instrument was launched on NASA's Terra satellite on December 18th, 1999 and has made measurements of carbon monoxide in the troposphere over the entire planet for the last nearly eight years accumulating a dataset approaching 2,000,000,000 measurements. It has significantly expanded our understanding of the production, transport and demise of atmospheric pollution on the planet and the results continue to surprise us all.

This talk will give a brief review of the history of MOPITT and then concentrate on some of the most interesting recent measurements including a biomass burning event in Indonesia in October 2006 which caused us to revise our understanding of the potential levels of pollution on the planet.

Title - TBA

Speaker

Institute

4:30 p.m., Thursday, November 29, 2007

No seminar this week

Thursday, December 6, 2007

Midlatitude SST - A fresh look at variability on fast oceanic and slow atmospheric timescales

Rick Danielson

Department of Oceanography
Dalhousie University

4:30 p.m., Thursday, December 13, 2007

No more seminars until the new year!

Merry Christmas Everybody!