Guillou, C. and Ellison, W. and Eymard, L. and Lamkaouchi, K. and Prigent, C. and Delbos, G. and Balana, G. and Boukabara, S.A. (1998) Impact of new permittivity measurements on sea surface emissivity modeling in microwaves. Radio Science, 33 (3). pp. 649-667.

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Official URL: https://www.scopus.com/inward/record.uri?eid=2-s2....

Abstract

As part of a measuring program dedicated to the analysis of the dielectric properties of seawater in the frequency range 3-89 GHz, a new dielectric permittivity model based on the standard Debye theory has been developed for remote sensing applications over the ocean below 40 GHz, together with polynomial interpolations at the millimeter frequencies 85.5 and 89 GHz. The aim of this paper is to test the relevance of these new dielectric measurements through statistical comparisons of radiative transfer predictions with satellite and airborne radiometric data between 18 and 89 GHz. A radiometric sensitivity analysis to the permittivity measurement errors is proposed, which yields a sea surface brightness temperature accuracy of at least 0.5 K below 20 GHz, 1 K at 24 GHz, and 1.5 K at 37 and 89 GHz. At frequencies less than 40 GHz, superiority of the revised Debye model is pointed out over the most commonly used model of Klein and Swift 1977. At millimeter frequencies the new permittivity expressions deviate significantly from the standard Debye predictions, especially at low temperature, suggesting the influence of a second "high-frequency" Debye relaxation. Our comparisons with radiometric data at 89 GHz and in the channel 85.5V of the special sensor microwave imager tend to support this hypothesis. The results emphasize the importance of an adequate modeling of the complex permittivity of seawater as input to the surface emissivity models, at any frequency of the microwave spectrum, and augur interesting outputs in both in-flight calibration and interpretation of satellite data.

Item Type: Article
Uncontrolled Keywords: Image sensors; Interpolation; Mathematical models; Measurement errors; Microwaves; Polynomials; Radiometry; Remote sensing; Satellites; Seawater; Sensitivity analysis; Statistical methods; Application programs; Dielectric properties; Electromagnetic wave emission; Forecasting; Microwave sensors; Microwave spectroscopy; Permittivity measurement; Radiometry; Remote sensing; Seawater; Sensitivity analysis; Surface waters; Temperature, Debye theory; Microwave imager; Radiative transfer; Surface emissivity model, Permittivity measurement; Permittivity, Dielectric measurements; Dielectric permittivities; Polynomial interpolation; Radiometric sensitivity; Remote sensing applications; Sea surface brightness temperature; Special sensor microwave imagers; Statistical comparisons
Subjects: Earth and Planetary Sciences
Divisions: SCIENTIFIC PRODUCTION > Earth and Planetary Sciences
Depositing User: Administrateur Eprints Administrateur Eprints
Last Modified: 31 Jan 2020 15:47
URI: http://eprints.umi.ac.ma/id/eprint/2993

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