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Rings of the North Brazil Current: Their structure and behavior inferred from observations and a numerical simulationLarge anticyclonic rings are shed from the retroflecting North Brazil Current (NBC) near 8 deg N in the tropical western Atlantic. New subsurface velocity and temperature measurements within three such rings are presented here and are found to be consistent with previous in situ and remotely sensed NBC ring measurements. A high-resolution numerical model of the Atlantic Ocean forced by monthly wind stress and an imposed meridional overturning cell is found to shed NBC rings that approximate those observed. The model rings are more surface-intensified than those observed and somewhat smaller in diameter. Both observed and modeled NBC rings move northwestward along the coast of South America with a speed of 8-16 cm/s, considerably slower than predicted by analytical theories describing westward ring propagation. At least 2-3 rings per year separate from the NBC retroflection. Annually, 1-3 rings translate intact from their formation region near 50 deg W to the islands of the southeastern Caribbean, where they disintegrate after a lifetime of about 100 days. This study is the first to make use of subsurface temperature and velocity data to compute the volume of the anomalous ring core. NBC rings may be responsible for 3-4 Sv of direct mass transport across the equatorial-tropical gyre boundary or 20-25% of the total upper ocean cross-gyre transport required by the Atlantic meridional overturning cell. Translating NBC rings may contribute 20% of the total meridional heat transport by the ocean at this latitude.
Document ID
19950057101
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Fratantoni, David M.
(University of Miami, Miami, FL United States)
Johns, William E.
(University of Miami, Miami, FL United States)
Townsend, Tamara L.
(NASA Stennis Space Center Bay Saint Louis, MS, United States)
Date Acquired
August 16, 2013
Publication Date
June 15, 1995
Publication Information
Publication: Journal of Geophysical Research
Volume: 100
Issue: C6
ISSN: 0148-0227
Subject Category
Oceanography
Accession Number
95A88700
Funding Number(s)
CONTRACT_GRANT: N00014-89-J1139
CONTRACT_GRANT: NOAA-NA-85WCH06134
Distribution Limits
Public
Copyright
Other

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