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Validation of the geostrophic method for estimating zonal currents at the equator from Geosat altimeter dataThe applicability of satellite altimeter data for estimating zonal current variability at the equator is assessed using the meriodionally differenced form of the geostrophic balance. Estimates of geostrophic zonal flow anomalies in the equatorial Pacific have been deduced from 17-day collinear altimeter data during the first year of the Geosat Exact Repeat Mission. Altimeter-derived geostrophic estimates agree well with in situ zonal current variability. Comparison of flow-frequency near-surface zonal current observed from equatorial moorings at 165 deg E, 140 deg W, and 110 deg W yield correlations of 0.83, 0.85, and 0.51, respectively, with a mean rms difference of 23 cm/sec. The inclusion of up to 11 ascending and descending Geosat tracks within the 9-deg band for every 17-day repeat effectively reduced the temporal sampling interval to 1.5 days at 165 deg E and 140 deg W. The 6.8-km along track spacing of the altimeter measurements provides sufficient resolution for the effective filtering of small-scale meridional noise, both instrumental and oceanic.
Document ID
19900042564
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Picaut, Joel
(Office de la Recherche Scientifique et Technique Outre-Mer Noumea, New Caledonia)
Camusat, Bruno
(ORSTOM Institut Francais de Recherche Scientifique pour le Developpement en Cooperation, Noumea, New Caledonia)
Busalacchi, Antonio J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mcphaden, Michael J.
(NOAA, Pacific Marine Environmental Laboratory, Seattle WA, United States)
Date Acquired
August 14, 2013
Publication Date
March 15, 1990
Publication Information
Publication: Journal of Geophysical Research
Volume: 95
ISSN: 0148-0227
Subject Category
Oceanography
Accession Number
90A29619
Distribution Limits
Public
Copyright
Other

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