Hydrographic Vertical Separation Surfaces (HyVSEPs) for the Tidal Waters of Canada

Since the advent of Global Navigation Satellite Systems, it has been possible to perform hydrographic survey reductions through the ellipsoid, which has the potential to simplify operations and improve bathymetric products. This technique requires a spatially continuous separation surface connecting chart datum (CD) to a geodetic ellipsoid. The Canadian Hydrographic Service (CHS), with support from the Canadian Geodetic Survey, has developed a new suite of such surfaces, termed Hydrographic Vertical Separations Surfaces, or HyVSEPs, for CD and seven tidal levels. They capture the spatial variability of the tidal datum and levels between tide gauges and offshore using semiempirical models coupling observations at tide stations with relative sea-level rise estimates, dynamic ocean model solutions, satellite altimetry, and a geoid model. HyVSEPs are available for all tidal waters of Canada, covering over seven million square kilometers of ocean and more than 200,000 kilometers of shoreline. This document provides an overview of the CHS's modeling approach, tools, methods, and procedures.

The HyVSEP for CD defines the new hydrographic datum for the tidal waters of Canada. HyVSEPs for other tidal levels are fundamental for coastal studies, climate change adaptation and the definition of the Canadian shoreline and offshore boundaries. HyVSEPs for inland waters are not discussed.     

Simulated eddy induced vertical velocities in a Gulf of Alaska model

Mesoscale eddies can distribute nutrients, heat and fresh water into the Gulf of Alaska (GOA) from the coastal margins. While many studies have investigated the physical characteristics of GOA eddies, their effects on passive-dispersive particles have not been previously simulated to investigate eddy induced upwelling. A climatologically forced Parallel Ocean Program simulation of the north Pacific Ocean with an online particle tracking scheme was used to simulate passive-dispersive particles in the Gulf of Alaska. In-eddy vertical Lagrangian velocities of the particles were calculated both inside and outside the eddies and showed upwelling rates are generally greater inside the eddies where the vertical velocities of the particles ranged from 0.2 to 0.7 m/day.     

Fossil–Lagerstätten

Possibly every palaeontologist, before and after Charles Darwin, has been well aware that the fossil record is very incomplete. Only a tiny percentage of the plants and animals alive at any one time in the past get preserved as fossils, both in terms of numbers of individuals and in terms of numbers of species. The palaeontologist attempting to reconstruct ancient ecosystems is therefore, in effect, trying to complete a jigsaw puzzle without the picture on the box lid and for which the majority of pieces are missing. Under normal preservational conditions probably only around 15 per cent of the species composing an ecosystem are preserved. Moreover, the fossil record is biased in favour of those animals and plants with hard, mineralized shells, skeletons or cuticles, and towards those living in marine environments. Thus, the preservational potential of a particular organism depends on two main factors: its constitution (better if it contains hard parts), and its habitat (better if it lives in an environment where sedimentary deposition occurs).     

High-resolution modelling of a coastal harbour in the presence of strong tides and significant river runoff

Ocean Dynamics - In the context of Canada’s Ocean Protection Plan (OPP), improved coastal and near-shore modelling is needed to enhance marine safety and emergency response capacity in the...     

The Southern Ontario All-sky Meteor Camera Network

We have developed an automated network of all-sky CCD video systems to detect medium–large meteoroids ablating over Southern Ontario, Canada. The system currently consists of five stations with the largest baseline being 180 km. Each site runs a video rate recorder with sufficient resolution to determine meteoroid trajectories with a typical precision of about 300 m but no worse than 1 km. The sensitivity of the camera is close to a stellar visual magnitude of +1 which allows for astrometric calibrations using field stars. Photometric procedures have also been developed and tested. The system has a limiting magnitude for meteors of about −2 with the current detection algorithm.