Swell as a turbulence source in shallow water
Two field investigations in an exposed shallow area outside Lofoten, western Norway, were conducted in 1995 and 1996. Direct measurements of turbulence were conducted from an underwater tower with acoustic current meters 6 m above the bottom. The tidal energy in this area is low and the wind conditi...
Main Authors: | , , , |
---|---|
Format: | Report |
Language: | English |
Published: |
ICES
2005
|
Subjects: | |
Online Access: | http://hdl.handle.net/11250/100649 |
id |
ftimr:oai:imr.brage.unit.no:11250/100649 |
---|---|
record_format |
openpolar |
spelling |
ftimr:oai:imr.brage.unit.no:11250/100649 2023-05-15T17:08:18+02:00 Swell as a turbulence source in shallow water Stiansen, Jan Erik Sundby, Svein Jenkins, Alastair D. Nilsen, Jan Even Øie 2005 374017 bytes application/pdf http://hdl.handle.net/11250/100649 eng eng ICES ICES CM documents 2005/O:26 http://hdl.handle.net/11250/100649 10 s. fish larvae zooplankton hydrography fiskelarver dyreplankton hydrografi VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 Working paper 2005 ftimr 2021-09-23T20:15:25Z Two field investigations in an exposed shallow area outside Lofoten, western Norway, were conducted in 1995 and 1996. Direct measurements of turbulence were conducted from an underwater tower with acoustic current meters 6 m above the bottom. The tidal energy in this area is low and the wind conditions during the experiment were mostly weak. Nevertheless, the turbulent kinetic energy dissipation rate at 20-25 m depth was in the range 10-7-10-5 W/kg. The only other possible energy source was long swell of wavelength 100-200 m that rolled in from the open sea. Analysis shows that the wave related water motion intermittently becomes unstable, inducing strong turbulent patches in parts of the wave orbit. The mechanism behind this process is not clear, but possible explanations may be local energy concentration or interaction of waves with different frequency. In many areas and situations this energy source is equal in force to tidal and wind generated turbulence. Simultaneous measurement of vertical profiles of zooplankton and fish larvae from a nearby location enables us to discuss swell-induced turbulence in an ecological context. Report Lofoten Institute for Marine Research: Brage IMR Lofoten Norway |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
topic |
fish larvae zooplankton hydrography fiskelarver dyreplankton hydrografi VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 |
spellingShingle |
fish larvae zooplankton hydrography fiskelarver dyreplankton hydrografi VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 Stiansen, Jan Erik Sundby, Svein Jenkins, Alastair D. Nilsen, Jan Even Øie Swell as a turbulence source in shallow water |
topic_facet |
fish larvae zooplankton hydrography fiskelarver dyreplankton hydrografi VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921 |
description |
Two field investigations in an exposed shallow area outside Lofoten, western Norway, were conducted in 1995 and 1996. Direct measurements of turbulence were conducted from an underwater tower with acoustic current meters 6 m above the bottom. The tidal energy in this area is low and the wind conditions during the experiment were mostly weak. Nevertheless, the turbulent kinetic energy dissipation rate at 20-25 m depth was in the range 10-7-10-5 W/kg. The only other possible energy source was long swell of wavelength 100-200 m that rolled in from the open sea. Analysis shows that the wave related water motion intermittently becomes unstable, inducing strong turbulent patches in parts of the wave orbit. The mechanism behind this process is not clear, but possible explanations may be local energy concentration or interaction of waves with different frequency. In many areas and situations this energy source is equal in force to tidal and wind generated turbulence. Simultaneous measurement of vertical profiles of zooplankton and fish larvae from a nearby location enables us to discuss swell-induced turbulence in an ecological context. |
format |
Report |
author |
Stiansen, Jan Erik Sundby, Svein Jenkins, Alastair D. Nilsen, Jan Even Øie |
author_facet |
Stiansen, Jan Erik Sundby, Svein Jenkins, Alastair D. Nilsen, Jan Even Øie |
author_sort |
Stiansen, Jan Erik |
title |
Swell as a turbulence source in shallow water |
title_short |
Swell as a turbulence source in shallow water |
title_full |
Swell as a turbulence source in shallow water |
title_fullStr |
Swell as a turbulence source in shallow water |
title_full_unstemmed |
Swell as a turbulence source in shallow water |
title_sort |
swell as a turbulence source in shallow water |
publisher |
ICES |
publishDate |
2005 |
url |
http://hdl.handle.net/11250/100649 |
geographic |
Lofoten Norway |
geographic_facet |
Lofoten Norway |
genre |
Lofoten |
genre_facet |
Lofoten |
op_source |
10 s. |
op_relation |
ICES CM documents 2005/O:26 http://hdl.handle.net/11250/100649 |
_version_ |
1766064027737260032 |