Fall 2006

Ocean Forecasts for Canadians: Improving safety at sea through prediction of ocean behaviour^*

Fraser Davidson¹ and Dan Wright²

1Department of Fisheries and Oceans
St. John's, NL
and
²Department of Fisheries and Oceans
Dartmouth, NS

4:30 p.m., Thursday, November 2, 2006

Abstract: If land rose and fell with the wind and shifted around daily, one might hesitate to go to work in the morning. However fishermen, sailors, oil explorers, search and rescue specialists, and other seafarers must cope daily with a highly changeable ocean. An emerging field in oceanography is now the prediction of the state of the ocean from hours, to days, to weeks to decades. The better we understand the ocean, the more we will be able to predict its motion, its temperature, its ice cover and its behavior. This is welcome news for those who work at sea, for biologists wanting to relate the ocean's physical environment to biological observations and to meteorologists forever seeking to improve their weather forecasts.

Interestingly enough, in order to forecast the future of the ocean, we need to test our ocean models and forecasting systems on well-observed passed events. Every ocean forecasting system requires careful validation through hindcasts and historical data validation.

This talk describes the emerging field of operational oceanography. We describe the differences between atmospheric weather forecasting and ocean weather forecasting and the challenges of the latter. The multidisciplinary and team nature of operational oceanography is described along with the variety of applications from Global to Regional systems. An overview of the present vision for Canada's operational ocean forecasting capability is given as well as the latest results in ocean forecasting initiatives.

^*Co-sponsored by CMOS.

Title: TBA

Speaker

Institute

4:30 p.m., Thursday, November 9, 2006

Abstract:

How Density Currents Set the Vertical Stratification of Deep Oceanic Basins and Lakes

Matthew Wells

Physical and Environmental Sciences
University of Toronto

4:30 p.m., Thursday, November 16, 2006

Abstract: Cooling or evaporation in marginal seas or shallow coastal embayments leads to the formation of dense water masses, which drain away in the form of density currents or underflows. In many cases the source water in the currents is initially denser than the bottom waters of the basin it flows into, but mixing dilutes the current so that it can intrude at mid-depth. Such small-scale mixing is difficult to parameterize in a large-scale numerical ocean models, but the depth at which deep waters spread has been shown to have important impacts on climate. I will present recent experimental measurements of the entrainment rates in density currents. Using these results I will show how the small scale mixing of the density currents will set the depth at which a density current intrudes into a stable stratification, and how the upwelling driven by a density current in a confined basin can set the large scale density stratification.

Title: TBA