Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990
Detailed measurements of internal properties of Arctic ice were made in Spring 1990 to relate acoustic properties to the physical properties of the ice. This report presents the procedures, analyses, and results of those studies. Some basic parameters measured in previous field studies were remeasur...
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ftdtic:ADA274326 2023-05-15T14:56:35+02:00 Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 Garrison, G. R. Williams, K. L. Mourad, P. D. Francois, R. E. Wen, T. WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB 1993-11 text/html http://www.dtic.mil/docs/citations/ADA274326 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA274326 en eng http://www.dtic.mil/docs/citations/ADA274326 APPROVED FOR PUBLIC RELEASE DTIC AND NTIS Snow Ice and Permafrost Acoustic Detection and Detectors Acoustics *ACOUSTIC VELOCITY *ACOUSTIC PROPERTIES *SEA ICE TEMPERATURE THICKNESS MONITORING CONDUCTIVITY INTERFACES LAYERS PHYSICAL PROPERTIES REFLECTION POROSITY CONSISTENCY THERMISTORS FREEZING ICE THERMAL CONDUCTIVITY PRESSURE SOUND CANOPIES TRANSDUCERS ABSORPTION ACOUSTIC ATTENUATION HYDROPHONES REFLECTIVITY DIFFUSIVITY MELTING POINT ARCTIC REGIONS ICE WATER INTERFACE ICE CANOPIES Text 1993 ftdtic 2016-02-20T08:38:41Z Detailed measurements of internal properties of Arctic ice were made in Spring 1990 to relate acoustic properties to the physical properties of the ice. This report presents the procedures, analyses, and results of those studies. Some basic parameters measured in previous field studies were remeasured; consistency between individual experiments strengthens our confidence in the results and the techniques used. Novel techniques were used to measure properties of growing ice, which was later cored, submerged, and remeasured. Results reported here have been summarized in the open literature (Williams et al., J. Acoust. Soc. Am., 92, 2075, 1992). The basic data and their processing are described here in detail. In the ice-growth and submergence study, a 2-m-square hole was cut though the ice canopy. Strings of hydrophones and thermistors were then suspended vertically in the hole, and the water froze around them. Frequent monitoring of ice temperature and the receipt of sound pulses from below, along with salinities determined from ice cores obtained a short distance away, gave insight into the freezing process and the formation of a skeletal layer above the ice/water interface. Periodic measurements of the reflectivity of the growing ice at 37-150 kHz gave further information on the skeletal structure. The sound speed in the skeletal layer varied from that of the water at the ice-/water interface to that of bulk ice at about 3 cm into the ice. Absorption of sound (in decibels per meter) was about three times greater near the interface, decreasing to that for bulk ice at 15-20 cm into the ice. Ice acoustic properties, Reflection, Sound speed, Attenuation, Ice bulk properties, Porosity, Thermal conductivity. Text Arctic Ice permafrost Sea ice Defense Technical Information Center: DTIC Technical Reports database Arctic |
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Open Polar |
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Defense Technical Information Center: DTIC Technical Reports database |
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ftdtic |
language |
English |
topic |
Snow Ice and Permafrost Acoustic Detection and Detectors Acoustics *ACOUSTIC VELOCITY *ACOUSTIC PROPERTIES *SEA ICE TEMPERATURE THICKNESS MONITORING CONDUCTIVITY INTERFACES LAYERS PHYSICAL PROPERTIES REFLECTION POROSITY CONSISTENCY THERMISTORS FREEZING ICE THERMAL CONDUCTIVITY PRESSURE SOUND CANOPIES TRANSDUCERS ABSORPTION ACOUSTIC ATTENUATION HYDROPHONES REFLECTIVITY DIFFUSIVITY MELTING POINT ARCTIC REGIONS ICE WATER INTERFACE ICE CANOPIES |
spellingShingle |
Snow Ice and Permafrost Acoustic Detection and Detectors Acoustics *ACOUSTIC VELOCITY *ACOUSTIC PROPERTIES *SEA ICE TEMPERATURE THICKNESS MONITORING CONDUCTIVITY INTERFACES LAYERS PHYSICAL PROPERTIES REFLECTION POROSITY CONSISTENCY THERMISTORS FREEZING ICE THERMAL CONDUCTIVITY PRESSURE SOUND CANOPIES TRANSDUCERS ABSORPTION ACOUSTIC ATTENUATION HYDROPHONES REFLECTIVITY DIFFUSIVITY MELTING POINT ARCTIC REGIONS ICE WATER INTERFACE ICE CANOPIES Garrison, G. R. Williams, K. L. Mourad, P. D. Francois, R. E. Wen, T. Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 |
topic_facet |
Snow Ice and Permafrost Acoustic Detection and Detectors Acoustics *ACOUSTIC VELOCITY *ACOUSTIC PROPERTIES *SEA ICE TEMPERATURE THICKNESS MONITORING CONDUCTIVITY INTERFACES LAYERS PHYSICAL PROPERTIES REFLECTION POROSITY CONSISTENCY THERMISTORS FREEZING ICE THERMAL CONDUCTIVITY PRESSURE SOUND CANOPIES TRANSDUCERS ABSORPTION ACOUSTIC ATTENUATION HYDROPHONES REFLECTIVITY DIFFUSIVITY MELTING POINT ARCTIC REGIONS ICE WATER INTERFACE ICE CANOPIES |
description |
Detailed measurements of internal properties of Arctic ice were made in Spring 1990 to relate acoustic properties to the physical properties of the ice. This report presents the procedures, analyses, and results of those studies. Some basic parameters measured in previous field studies were remeasured; consistency between individual experiments strengthens our confidence in the results and the techniques used. Novel techniques were used to measure properties of growing ice, which was later cored, submerged, and remeasured. Results reported here have been summarized in the open literature (Williams et al., J. Acoust. Soc. Am., 92, 2075, 1992). The basic data and their processing are described here in detail. In the ice-growth and submergence study, a 2-m-square hole was cut though the ice canopy. Strings of hydrophones and thermistors were then suspended vertically in the hole, and the water froze around them. Frequent monitoring of ice temperature and the receipt of sound pulses from below, along with salinities determined from ice cores obtained a short distance away, gave insight into the freezing process and the formation of a skeletal layer above the ice/water interface. Periodic measurements of the reflectivity of the growing ice at 37-150 kHz gave further information on the skeletal structure. The sound speed in the skeletal layer varied from that of the water at the ice-/water interface to that of bulk ice at about 3 cm into the ice. Absorption of sound (in decibels per meter) was about three times greater near the interface, decreasing to that for bulk ice at 15-20 cm into the ice. Ice acoustic properties, Reflection, Sound speed, Attenuation, Ice bulk properties, Porosity, Thermal conductivity. |
author2 |
WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB |
format |
Text |
author |
Garrison, G. R. Williams, K. L. Mourad, P. D. Francois, R. E. Wen, T. |
author_facet |
Garrison, G. R. Williams, K. L. Mourad, P. D. Francois, R. E. Wen, T. |
author_sort |
Garrison, G. R. |
title |
Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 |
title_short |
Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 |
title_full |
Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 |
title_fullStr |
Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 |
title_full_unstemmed |
Sound Speed, Reflectivity, Absorption, amd Thermal Diffusivity Measurements in Arctic Ice in 1990 |
title_sort |
sound speed, reflectivity, absorption, amd thermal diffusivity measurements in arctic ice in 1990 |
publishDate |
1993 |
url |
http://www.dtic.mil/docs/citations/ADA274326 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA274326 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Ice permafrost Sea ice |
genre_facet |
Arctic Ice permafrost Sea ice |
op_source |
DTIC AND NTIS |
op_relation |
http://www.dtic.mil/docs/citations/ADA274326 |
op_rights |
APPROVED FOR PUBLIC RELEASE |
_version_ |
1766328679234797568 |