Interferometric SAR imaging of ocean surface currents and wavefields
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Authors
Marom, Moshe
Subjects
Interferometric SAR
Scene coherence time
2D wavenumber spectra
Surface Currents
Scene coherence time
2D wavenumber spectra
Surface Currents
Advisors
Thornton, E.B.
Date of Issue
1990-06
Date
June 1990
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
The potential of a method to remotely measure near-surface currents and dominant wave spectra using Interferometric Synthetic Aperture Radar INSAR is demonstrated. INSAR consists of a single conventional SAR augmented by an additional receiving antenna. The phase difference between corresponding SAR image scenes observed by the antennas provides an interferogram directly proportional to the ocean surface velocity field. This direct motion detection by INSAR suggests a significant advance compared with conventional SAR where the response to the moving ocean surface is indirectly related to complex modulation of the surface reflectivity by longer waves and currents. An experiment using an airborne INSAR to measure ocean surface currents and wave fields, compared with simultaneous ground truth measurements using Lagrangian drifters and wave array data was conducted in Monterey Bay. INSAR measured mean current magnitude estimates agree to within 10% compared with conventional measurements. The INSAR image wavenumber spectrum is consistent with the in situ directional spectrum and with predicted numerical refraction model outputs. Wavelength of the observed swells is better agreement (correlation better than 0.9) than wave direction. An attempt to estimate the scene coherence time for L-band SAR was made by taking advantage of the almost simultaneously acquired SAR and INSAR images. The obtained mean scene coherence time (100 msec) is consistent with sparse observed estimates in the literature.
Type
Thesis
Description
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted.
Series/Report No
Department
Oceanography
Organization
Identifiers
NPS Report Number
Sponsors
Funding
Format
xv, 201 p. :|bill. ;|c28 cm.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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.