Characterization of surface radar cross sections at W-band at moderate incidence angles

Battaglia, A., Wolde, M., D'Adderio, L. P., Nguyen, C., Fois, F., Illingworth, A. ORCID: https://orcid.org/0000-0002-5774-8410 and Midthassel, R. (2017) Characterization of surface radar cross sections at W-band at moderate incidence angles. IEEE Transactions on Geoscience and Remote Sensing, 55 (7). pp. 3846-3859. ISSN 0196-2892 doi: 10.1109/TGRS.2017.2682423

Abstract/Summary

This paper presents the results of a recent flight campaign conducted over the Great Lakes region and reports the first observations of the W-band normalized backscattered cross section ( σ0 ) for V and H polarization and the linear depolarization ratios (LDRs) from different types of surfaces at moderate incidence angles (<70°). For sea surfaces, while the observed σ0 behaves as previously reported at small incidence angles, it features a marked decrease with increasing incidence angles between 20° and 50°. There is a strong dependence of normalized backscattered cross sections both on the wind speed and on the wind direction, with larger values found in the presence of higher wind speeds and when the radar antenna is looking upwind. This is in line with theoretical models (though models tend to overpredict the range of variability at a given incidence angle) and with observations at lower frequencies. The LDRs are steadily increasing from values certainly lower than −30 dB, at vertical incidence, to the values of about −10 dB, at the incidence angles of about 60°–70°, with a good matching between observations and theoretical predictions. On the other hand, land surface backscattering properties are not characterized by a strong angular dependence: σ0 and LDR values typically range between −20 and 0 dB and between −15 and −5 dB, respectively. This paper is relevant for spaceborne concepts of W-band radars, which envisage moderate incidence angles to achieve a broad swath needed for global coverage.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/71154
Identification Number/DOI	10.1109/TGRS.2017.2682423
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	IEEE Geoscience and Remote Sensing Society
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