Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean
Decrease in Arctic Ocean perennial sea-ice has been observed in recent decades. As sea-ice continues to decline, marine traffic will increase and the United States will require a more active military presence in the Arctic. Future Arctic conditions must be forecasted with increased accuracy to allow...
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ftdtic:ADA561847 2023-05-15T14:48:42+02:00 Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean Schmidt, Brandon K NAVAL POSTGRADUATE SCHOOL MONTEREY CA 2012-03 text/html http://www.dtic.mil/docs/citations/ADA561847 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA561847 en eng http://www.dtic.mil/docs/citations/ADA561847 Approved for public release; distribution is unlimited. DTIC Snow Ice and Permafrost *SEA ICE ARCTIC OCEAN BEAUFORT SEA DRAG ROUGHNESS SONAR THESES TURBULENCE WAKE WATER TRAFFIC ICE CONCENTRATION ICE MORPHOLOGY ICE ROUGHNESS ICE KEEL MIXED LAYERS OCEAN HEAT FLUX MIXING LENGTH DISSIPATION RATE DRAG COEFFICIENT Text 2012 ftdtic 2016-02-24T07:56:07Z Decrease in Arctic Ocean perennial sea-ice has been observed in recent decades. As sea-ice continues to decline, marine traffic will increase and the United States will require a more active military presence in the Arctic. Future Arctic conditions must be forecasted with increased accuracy to allow for proper planning with regard to the nation's changing role in the region. It is the goal of this thesis to contribute to the knowledge of turbulence and mixing associated with ice keels in the Arctic Ocean in order to improve the accuracy of predictive coupled ocean/ice/atmospheric models. At Applied Physics Laboratory Ice Station 2011, a 3-dimensional (3-D) sonar was used to record high resolution morphological measurements of an ice keel approximately 33 m long by 29 m across and 10 m deep. Sensors were deployed in the water column approximately 10 m from the keel to record water properties of salinity, temperature, and 3-D velocity at selected depths in the upper water column. These observations were used to make calculations of turbulence within the mixed layer, in order to gain a greater understanding of how keels affect turbulent drag and heat fluxes in the upper ocean. Results indicate that keels generate significant turbulence and mixing in the upper ocean, even during benign weather conditions in which there is little surface forcing. Keels increase the kinetic energy of the upper ocean through production of turbulent eddies during times of weak stratification and the generation of internal waves during times of strong stratification. Keel-induced turbulence and mixing may lead to entrainment of warmer water underlying the surface mixed layer that could be a contributor to ice melting. Calculation of the quadratic drag coefficient Cw also indicated that Cw varies greatly with water column stratification and ice undersurface roughness. The original document contains color images. Text Arctic Arctic Ocean Beaufort Sea Ice permafrost Sea ice Defense Technical Information Center: DTIC Technical Reports database Arctic Arctic Ocean |
institution |
Open Polar |
collection |
Defense Technical Information Center: DTIC Technical Reports database |
op_collection_id |
ftdtic |
language |
English |
topic |
Snow Ice and Permafrost *SEA ICE ARCTIC OCEAN BEAUFORT SEA DRAG ROUGHNESS SONAR THESES TURBULENCE WAKE WATER TRAFFIC ICE CONCENTRATION ICE MORPHOLOGY ICE ROUGHNESS ICE KEEL MIXED LAYERS OCEAN HEAT FLUX MIXING LENGTH DISSIPATION RATE DRAG COEFFICIENT |
spellingShingle |
Snow Ice and Permafrost *SEA ICE ARCTIC OCEAN BEAUFORT SEA DRAG ROUGHNESS SONAR THESES TURBULENCE WAKE WATER TRAFFIC ICE CONCENTRATION ICE MORPHOLOGY ICE ROUGHNESS ICE KEEL MIXED LAYERS OCEAN HEAT FLUX MIXING LENGTH DISSIPATION RATE DRAG COEFFICIENT Schmidt, Brandon K Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean |
topic_facet |
Snow Ice and Permafrost *SEA ICE ARCTIC OCEAN BEAUFORT SEA DRAG ROUGHNESS SONAR THESES TURBULENCE WAKE WATER TRAFFIC ICE CONCENTRATION ICE MORPHOLOGY ICE ROUGHNESS ICE KEEL MIXED LAYERS OCEAN HEAT FLUX MIXING LENGTH DISSIPATION RATE DRAG COEFFICIENT |
description |
Decrease in Arctic Ocean perennial sea-ice has been observed in recent decades. As sea-ice continues to decline, marine traffic will increase and the United States will require a more active military presence in the Arctic. Future Arctic conditions must be forecasted with increased accuracy to allow for proper planning with regard to the nation's changing role in the region. It is the goal of this thesis to contribute to the knowledge of turbulence and mixing associated with ice keels in the Arctic Ocean in order to improve the accuracy of predictive coupled ocean/ice/atmospheric models. At Applied Physics Laboratory Ice Station 2011, a 3-dimensional (3-D) sonar was used to record high resolution morphological measurements of an ice keel approximately 33 m long by 29 m across and 10 m deep. Sensors were deployed in the water column approximately 10 m from the keel to record water properties of salinity, temperature, and 3-D velocity at selected depths in the upper water column. These observations were used to make calculations of turbulence within the mixed layer, in order to gain a greater understanding of how keels affect turbulent drag and heat fluxes in the upper ocean. Results indicate that keels generate significant turbulence and mixing in the upper ocean, even during benign weather conditions in which there is little surface forcing. Keels increase the kinetic energy of the upper ocean through production of turbulent eddies during times of weak stratification and the generation of internal waves during times of strong stratification. Keel-induced turbulence and mixing may lead to entrainment of warmer water underlying the surface mixed layer that could be a contributor to ice melting. Calculation of the quadratic drag coefficient Cw also indicated that Cw varies greatly with water column stratification and ice undersurface roughness. The original document contains color images. |
author2 |
NAVAL POSTGRADUATE SCHOOL MONTEREY CA |
format |
Text |
author |
Schmidt, Brandon K |
author_facet |
Schmidt, Brandon K |
author_sort |
Schmidt, Brandon K |
title |
Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean |
title_short |
Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean |
title_full |
Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean |
title_fullStr |
Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean |
title_full_unstemmed |
Observations of Hydraulic Roughness and Form Drag in the Wake of a Deep Ice Keel in the Arctic Ocean |
title_sort |
observations of hydraulic roughness and form drag in the wake of a deep ice keel in the arctic ocean |
publishDate |
2012 |
url |
http://www.dtic.mil/docs/citations/ADA561847 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA561847 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Beaufort Sea Ice permafrost Sea ice |
genre_facet |
Arctic Arctic Ocean Beaufort Sea Ice permafrost Sea ice |
op_source |
DTIC |
op_relation |
http://www.dtic.mil/docs/citations/ADA561847 |
op_rights |
Approved for public release; distribution is unlimited. |
_version_ |
1766319786406445056 |