A Tomographic View of the Gulf Stream Southern Recirculation Gyre at 38 deg N, 55 deg W

• Main Author: Chester, David B.
• Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
• Format: Text
• Language: English
• Published: 1993
• Subjects: Physical and Dynamic Oceanography; Acoustic Detection and Detectors; *OCEAN CURRENTS; *SOUND TRANSMISSION; *GULF STREAM; *RECIRCULATION; VELOCITY; MEASUREMENT; RADIATION; ENERGY; STATISTICS; MOTION; THESES; VORTICES; KINETICS; TRAVEL; ACOUSTICS; SIGNATURES; ARTIFICIAL SATELLITES; INFRARED IMAGES; ESTIMATES; REGIONS; FAR FIELD; TRAVEL TIME; STREAMS; MOMENTUM; TRANSMITTER RECEIVERS; NORTH ATLANTIC OCEAN; OCEAN MODELS; UNDERWATER ACOUSTICS; HEAT; RINGS; ORDER STATISTICS; TOMOGRAPHY; EDDIES(FLUID MECHANICS); ARRAYS; LIGHT; STRUCTURES; CORES; TEMPERATURE; GULFS; *OCEAN CIRCULATION; VORTICITY; GYRES; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA279434; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA279434

Reciprocal acoustic transmissions made in a region just south of the Gulf Stream are analyzed to determine the structure and variability of temperature, current velocity, and vorticity fields at the northern extent of the southern recirculation gyre. A pentagonal array of tomographic transceivers was situated in a region centered at 38 deg N, 55 deg W from November, 1988 to August, 1989. Daily-averaged acoustic transmissions yielded travel times which were inverted to obtain estimates of range-averaged temperature and current velocity fields, and area-averaged relative vorticity fields. The acoustically determined estimates are consistent with current meter measurements and satellite infrared imagery. The signature of cold-core rings is clearly evident in the sections. Spectral estimates of the fields are dominated by motions with periodicities ranging from 32-128 days. Second-order statistics, such as eddy kinetic energies, and heat and momentum fluxes, are also estimated. The integrating nature of the tomographic measurement has been exploited to shed some light on the radiation of eddy energy from the Gulf Stream. Results of a diagnosis in terms of Eliassen-Palm flux vectors suggest that the Gulf Stream is the source of wave energy radiating into the far field and found in the interior of the North Atlantic subtropical gyre. Gulf Stream southern recirculation gyre, Acoustic tomography, Gulf Stream.