An investigation of cold overflow over the Iceland/Faeroes Ridge
Authors
Tunnicliffe, Peter A.
Subjects
Iceland/Faeroes Ridge
Overflow
Parabolic Equation Model
Overflow
Parabolic Equation Model
Advisors
Bourke, Robert H.
Chiu, Ching-Sang
Date of Issue
1990-12
Date
December 1990
Publisher
Monterey, California: Naval Postgraduate School
Language
Abstract
Hydrographic data were analyzed to determine spatial and temporal variability of the overflow of cold, fresh Arctic water over the Iceland/Faeroes Ridge into the Iceland Basin during both winter and summer. Regions of frequent intermittent overflow were located together with areas that remain relatively unaffected by this process. A time series of near bottom temperatures revealed a possible link between significant overflow events and local wind fields which may result in a seasonal contrast in conditions. Two overflow mechanisms were identified: an intermittent plume-like flow promoted by local wind forcing; and a continuous thin veil of mixed overflow water formed from more significantly sized eddiesfilaments located on top of the ridge. Estimates were made as to the probable contribution of both mechanisms to the total transport of Norwegian Sea water into the North Atlantic Ocean. Dynamic models of overflow were reviewed and, based on hydrographic results, a probable mechanism for overflow was proposed. Sound speed profiles were constructed representing the presence absence of overflow events and predicted sonar ranges were computed using a range-dependent parabolic equation model. Major effects on acoustic propagation are shown to be confined to regions close to the top of the rise, even during overflow events; however, large reduction in sonar ranges are predicted for areas on top of the ridge, even at low frequencies (100 Hz). Analysis of observations in the area suggest that acoustic variability in the region can be related to small changes in sea surface temperature and consequently may lead to a prediction of acoustic conditions in the region using AVHRR imagery.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
x, 96 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
Copyright is reserved by the copyright owner