Analysis of Central Arctic Noise Events.
Digital ambient noise data from the FRAM IV experiment of April 1982 were searched for ambient noise transients using a detection program. The time series of the resulting detections were examined visually to categorize each detection as a transient, artifact or false alarm. The transient events wer...
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ftdtic:ADA190253 2023-05-15T14:58:02+02:00 Analysis of Central Arctic Noise Events. Townsend-Manning, Mary MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING 1987-06 text/html http://www.dtic.mil/docs/citations/ADA190253 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA190253 en eng http://www.dtic.mil/docs/citations/ADA190253 APPROVED FOR PUBLIC RELEASE DTIC AND NTIS Acoustics Computer Programming and Software *AMBIENT NOISE *BACKGROUND NOISE *TRANSIENTS *COMPUTER PROGRAMS ACOUSTIC DATA ANGLES ARCTIC OCEAN ACOUSTIC ARRAYS ARRIVAL DATA BASES DATA PROCESSING DELAY DENSITY DETECTION DIGITAL SYSTEMS DIPOLES FALSE ALARMS HIGH RATE HORIZONTAL ORIENTATION HYDROPHONES LEVEL(QUANTITY) MAGNETIC TAPE QUIET ACOUSTIC REFRACTION ACOUSTIC SCATTERING SIGNAL TO NOISE RATIO ACOUSTIC SIGNALS SOUND TRANSMISSION SOURCES SPATIAL DISTRIBUTION STRENGTH(GENERAL) THRESHOLD EFFECTS TIME INTERVALS TIME SERIES ANALYSIS ALGORITHMS LEAST SQUARES METHOD LINEAR ARRAYS BEARING(DIRECTION) LOW FREQUENCY MULTICHANNEL PEAK VALUES PACK ICE UNDERICE PROBABILITY DISTRIBUTION FUNCTIONS LOW PRESSURE SPRING SEASON THESES Barents abyssal plain Interarrival time Ambient noise transients. Text 1987 ftdtic 2016-02-19T10:52:08Z Digital ambient noise data from the FRAM IV experiment of April 1982 were searched for ambient noise transients using a detection program. The time series of the resulting detections were examined visually to categorize each detection as a transient, artifact or false alarm. The transient events were located in space using time delays between signal arrival at different hydrophones. The cross shape of the FRAM IV horizontal array permitted location in both bearing and range. The source strength of each event was calculated using a simple dipole source model. Refraction and scattering of the acoustic path in the Arctic Ocean was taken into account. The overall number of events detected, and hence their interarrival times and spatial density, were all affected by the background ambient noise level. The detection program used the same threshold signal-to-noise level for all data tapes, so when ambient noise level were low more detections occurred. The mean interarrival time between events was 100 seconds. The interarrival time fit a J shaped gamma probability distribution. The number of events detected per area decreased with range from the array center. Half of the events occurred within 3000 meters of the array. In this area there were 0.3 events per square kilometer per hour. The event population showed no predominant angular dependence. The strengths calculated using the simple dipole model had a mean of 430 kN overall and 260 kN during quiet times. Stronger events occurred during times with high ambient noise levels. Text Arctic Arctic Ocean Defense Technical Information Center: DTIC Technical Reports database Arctic Arctic Ocean Barents Abyssal Plain ENVELOPE(40.000,40.000,85.000,85.000) |
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Open Polar |
collection |
Defense Technical Information Center: DTIC Technical Reports database |
op_collection_id |
ftdtic |
language |
English |
topic |
Acoustics Computer Programming and Software *AMBIENT NOISE *BACKGROUND NOISE *TRANSIENTS *COMPUTER PROGRAMS ACOUSTIC DATA ANGLES ARCTIC OCEAN ACOUSTIC ARRAYS ARRIVAL DATA BASES DATA PROCESSING DELAY DENSITY DETECTION DIGITAL SYSTEMS DIPOLES FALSE ALARMS HIGH RATE HORIZONTAL ORIENTATION HYDROPHONES LEVEL(QUANTITY) MAGNETIC TAPE QUIET ACOUSTIC REFRACTION ACOUSTIC SCATTERING SIGNAL TO NOISE RATIO ACOUSTIC SIGNALS SOUND TRANSMISSION SOURCES SPATIAL DISTRIBUTION STRENGTH(GENERAL) THRESHOLD EFFECTS TIME INTERVALS TIME SERIES ANALYSIS ALGORITHMS LEAST SQUARES METHOD LINEAR ARRAYS BEARING(DIRECTION) LOW FREQUENCY MULTICHANNEL PEAK VALUES PACK ICE UNDERICE PROBABILITY DISTRIBUTION FUNCTIONS LOW PRESSURE SPRING SEASON THESES Barents abyssal plain Interarrival time Ambient noise transients. |
spellingShingle |
Acoustics Computer Programming and Software *AMBIENT NOISE *BACKGROUND NOISE *TRANSIENTS *COMPUTER PROGRAMS ACOUSTIC DATA ANGLES ARCTIC OCEAN ACOUSTIC ARRAYS ARRIVAL DATA BASES DATA PROCESSING DELAY DENSITY DETECTION DIGITAL SYSTEMS DIPOLES FALSE ALARMS HIGH RATE HORIZONTAL ORIENTATION HYDROPHONES LEVEL(QUANTITY) MAGNETIC TAPE QUIET ACOUSTIC REFRACTION ACOUSTIC SCATTERING SIGNAL TO NOISE RATIO ACOUSTIC SIGNALS SOUND TRANSMISSION SOURCES SPATIAL DISTRIBUTION STRENGTH(GENERAL) THRESHOLD EFFECTS TIME INTERVALS TIME SERIES ANALYSIS ALGORITHMS LEAST SQUARES METHOD LINEAR ARRAYS BEARING(DIRECTION) LOW FREQUENCY MULTICHANNEL PEAK VALUES PACK ICE UNDERICE PROBABILITY DISTRIBUTION FUNCTIONS LOW PRESSURE SPRING SEASON THESES Barents abyssal plain Interarrival time Ambient noise transients. Townsend-Manning, Mary Analysis of Central Arctic Noise Events. |
topic_facet |
Acoustics Computer Programming and Software *AMBIENT NOISE *BACKGROUND NOISE *TRANSIENTS *COMPUTER PROGRAMS ACOUSTIC DATA ANGLES ARCTIC OCEAN ACOUSTIC ARRAYS ARRIVAL DATA BASES DATA PROCESSING DELAY DENSITY DETECTION DIGITAL SYSTEMS DIPOLES FALSE ALARMS HIGH RATE HORIZONTAL ORIENTATION HYDROPHONES LEVEL(QUANTITY) MAGNETIC TAPE QUIET ACOUSTIC REFRACTION ACOUSTIC SCATTERING SIGNAL TO NOISE RATIO ACOUSTIC SIGNALS SOUND TRANSMISSION SOURCES SPATIAL DISTRIBUTION STRENGTH(GENERAL) THRESHOLD EFFECTS TIME INTERVALS TIME SERIES ANALYSIS ALGORITHMS LEAST SQUARES METHOD LINEAR ARRAYS BEARING(DIRECTION) LOW FREQUENCY MULTICHANNEL PEAK VALUES PACK ICE UNDERICE PROBABILITY DISTRIBUTION FUNCTIONS LOW PRESSURE SPRING SEASON THESES Barents abyssal plain Interarrival time Ambient noise transients. |
description |
Digital ambient noise data from the FRAM IV experiment of April 1982 were searched for ambient noise transients using a detection program. The time series of the resulting detections were examined visually to categorize each detection as a transient, artifact or false alarm. The transient events were located in space using time delays between signal arrival at different hydrophones. The cross shape of the FRAM IV horizontal array permitted location in both bearing and range. The source strength of each event was calculated using a simple dipole source model. Refraction and scattering of the acoustic path in the Arctic Ocean was taken into account. The overall number of events detected, and hence their interarrival times and spatial density, were all affected by the background ambient noise level. The detection program used the same threshold signal-to-noise level for all data tapes, so when ambient noise level were low more detections occurred. The mean interarrival time between events was 100 seconds. The interarrival time fit a J shaped gamma probability distribution. The number of events detected per area decreased with range from the array center. Half of the events occurred within 3000 meters of the array. In this area there were 0.3 events per square kilometer per hour. The event population showed no predominant angular dependence. The strengths calculated using the simple dipole model had a mean of 430 kN overall and 260 kN during quiet times. Stronger events occurred during times with high ambient noise levels. |
author2 |
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING |
format |
Text |
author |
Townsend-Manning, Mary |
author_facet |
Townsend-Manning, Mary |
author_sort |
Townsend-Manning, Mary |
title |
Analysis of Central Arctic Noise Events. |
title_short |
Analysis of Central Arctic Noise Events. |
title_full |
Analysis of Central Arctic Noise Events. |
title_fullStr |
Analysis of Central Arctic Noise Events. |
title_full_unstemmed |
Analysis of Central Arctic Noise Events. |
title_sort |
analysis of central arctic noise events. |
publishDate |
1987 |
url |
http://www.dtic.mil/docs/citations/ADA190253 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA190253 |
long_lat |
ENVELOPE(40.000,40.000,85.000,85.000) |
geographic |
Arctic Arctic Ocean Barents Abyssal Plain |
geographic_facet |
Arctic Arctic Ocean Barents Abyssal Plain |
genre |
Arctic Arctic Ocean |
genre_facet |
Arctic Arctic Ocean |
op_source |
DTIC AND NTIS |
op_relation |
http://www.dtic.mil/docs/citations/ADA190253 |
op_rights |
APPROVED FOR PUBLIC RELEASE |
_version_ |
1766330127516434432 |