Oceanographic mesoscale features off the West Greenland coast : satellite image analysis and modelling

Subramanian, Vembu (2000) Oceanographic mesoscale features off the West Greenland coast : satellite image analysis and modelling. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (5MB)

Abstract

The establishment of a station to receive National Oceanic Atmospheric Administration (NOAA) satellite data at the Northwest Atlantic Fisheries Centre, St. John's, Newfoundland in 1994 greatly expanded the AVHRR coverage of the coastal waters of the Newfoundland and Labrador region to include the West and East Greenland waters. The thermal infrared imagery selected from the data received at this station provide a valuable new perspective on oceanographic phenomena occurring in the waters off the coast of West Greenland. This perspective could not be attained using conventional shipboard and in situ oceanographic measurement techniques. A rich spectrum of mesoscale oceanographic features is revealed in the analyzed thermal infrared imagery, and the spatial and temporal scales of the various features such as West Greenland Current meanders, frontal waves and eddies are described first in this thesis. Then, a three-dimensional, primitive equation, regional, ocean circulation model of the West Greenland region based on the NOAA Geophysical Fluid Dynamics Laboratory (GFDL) Modular Ocean Model (MOM2 - version 2) code is used to elucidate the dynamics involved in modelling the current meanders and eddies. First, a numerical experiment was carried out by forcing the model from rest using an idealized initial density front with a passive open boundary condition in which there is no forcing specified at the open boundary to test and verify the satisfactory behaviour of the MOM2 model. In response to the initial forcing, two baroclinic Kelvin waves were formed and the waves were found to propagate out of the model domain through the open boundaries without affecting the interior solution. Next, a numerical experiment was carried out to investigate the combined effects of wind and thermal forcings in the generation of current meanders and eddies. Results of the experiment show the development of a poleward surface current and an opposite flowing undercurrent. In time the core of the undercurrent becomes wider and seen to displace the core of the surface current, suggesting that there may be both vertical and horizontal shear. As a result the currents could become unstable, and lead to the development of current meanders and eddies.

Actions (login required)

View Item