Evaluation of GEOSAT data and application to variability of the northeast Pacific Ocean

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Authors
Campbell, Jeffrey William
Subjects
Advisors
Date of Issue
1988
Date
Publisher
Monterey California. Naval Postgraduate School
Language
en_US
Abstract
Part of the N.E. Pacific was studied to evaluate and use altimetric data from the Navy Geodetic Satellite GEOSAT. The zero-order accuracy of the major GEOSAT geophysical data record (GDR) channels was verified, and occasional gaps in the altimeter coverage were noted. GEOSAT's 17-day repeat orbit allowed use of collinear-track processing to create profiles of the difference between the sea surface height along a given satellite repeat, and the mean sea surface height along that repeat's groundtrack. Detrending of sea surface bias and tilt on each repeat reduced orbit and other long wavelength errors in the difference profiles. Corrections provided on the GEOSAT GDR were examined for their effects on the difference profiles of three test arcs. It was found that only the ocean tide, electromagnetic bias, and inverted barometer corrections varied enough over the arc lengths (approx. 4400 km) to have any noticeable effect on the difference profiles. Only the ocean tide correction was accurate enough to warrant using it to adjust the sea surface heights. Recommended processing of GEOSAT data for the area included making the ocean tide correction, three-point block averaging successive sea surface heights, and forming the mean height profiles from 18 repeat cycles (to reduce aliasing of the M2 tidal component), A set of difference profiles for one GEOSAT arc indicated that a reasonable estimate of GEOSAT's system precision was approx. 4.5 cm (RMS). The mid wavelength range (100-500 km) of these profiles was found to be the only range in which oceanic mesoscale features could be separated from altimeter errors
Type
Thesis
Description
CIVINS (Civilian Institutions) Thesis document
Department
Organization
Woods Hole Oceanographic Institution
Massachusetts Institute of Technology
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NPS Report Number
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Funder
CIVINS
Format
163 leaves.
Citation
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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