Arctic Acoustic Tomography MIZEX 84.

This contract supported an experiment conducted in the Norwegian Sea during May-June 1984 to assess the possibilities of using ocean acoustic tomography as a measuring tool in the Arctic. The object of the experiment was to identify and determine the temporal stability (coherence), and resolvability...

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Bibliographic Details
Main Author: Spindel,R C
Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
Format: Text
Language:English
Published: 1985
Subjects:
Physical and Dynamic Oceanography
Acoustics
*SOUND TRANSMISSION
*TOMOGRAPHY
COMPUTERIZED SIMULATION
FREQUENCY
MEASUREMENT
TEMPERATURE
STABILITY
MODELS
PATHS
REFLECTION
DRIFT
ICE
PULSES
SIGNALS
RECEIVERS
OCEANS
ARRIVAL
NORWEGIAN SEA
UNDERWATER SOUND
DEEP OCEANS
SEA ICE
ARCTIC REGIONS
UNDERWATER SOUND EQUIPMENT
*Acoustic tomography
MIZEX 84 Project
Arctic
Arctic Sound
Norwegian Sea
Sea ice
Online Access:http://www.dtic.mil/docs/citations/ADA154426
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA154426
Description
Summary:This contract supported an experiment conducted in the Norwegian Sea during May-June 1984 to assess the possibilities of using ocean acoustic tomography as a measuring tool in the Arctic. The object of the experiment was to identify and determine the temporal stability (coherence), and resolvability, of Arctic acoustic paths. 'Identification' refers to the ability to match a pulse arrival with a particular ray path, primarily through computer modelling. Resolvable rays are those that arrive sufficiently far apart in time so as to be distinct and stable. Unlike the deep temperature ocean, where there are many wholly refracted paths, the upward refracting Arctic sound speed profile causes ray paths to reflect off the ice-covered surface of the permanent pack and the mixed ice-covered and ice-free surface of the marginal ice zones. The reflection process is time-varying and hence leads to resolvability, identification and stability questions that do not arise in the case of entirely refracted paths. A 224 Hz acoustic source, moored in an ice-free region, transmitted phase coded, frequency stable signals to receivers fixed on the bottom and receivers drifting with the icepack at ranges of approximately 150 km. Preliminary analysis indicates that the received signals, particularly those from paths that interact with the ice-free surface, appear to have sufficiently stability for tomographic purposes.

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