The emissivity of foam-covered water surface at L-band: Theoretical modeling and experimental results from the frog 2003 field experiment
Type | Article | ||||||||
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Date | 2005-05 | ||||||||
Language | English | ||||||||
Author(s) | Camps A1, Vall-Ilossera M1, Villarino R1, Reul Nicolas![]() |
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Affiliation(s) | 1 : Univ Politecn Catalunya, Dept Signal Theory & Commun, E-08034 Barcelona, Spain. 2 : IFREMER, Dept Oceanog Phys & Spatiale, Lab Oceanog Spatiale, F-29280 Plouzane, France. |
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Source | Ieee Transactions On Geoscience And Remote Sensing (0196-2892) (Ieee-inst Electrical Electronics Engineers Inc), 2005-05 , Vol. 43 , N. 5 , P. 925-937 | ||||||||
DOI | 10.1109/TGRS.2004.839651 | ||||||||
WOS© Times Cited | 57 | ||||||||
Keyword(s) | brightness temperature, emission, foam, microwave radiometry, salinity, sea | ||||||||
Abstract | Sea surface salinity can be measured by microwave radiometry at L-band (1400-1427 MHz). This frequency is a compromise between sensitivity to the salinity, small atmospheric perturbation, and reasonable pixel resolution. The description of the ocean emission depends on two main factors: 1) the sea water permittivity, which is a function of salinity, temperature, and frequency, and 2) the sea surface state, which depends on the wind-induced wave spectrum, swell, and rain-induced roughness spectrum, and by the foam coverage and its emissivity. This study presents a simplified two-layer emission model for foam-covered water and the results of a controlled experiment to measure the foam emissivity as a function of salinity, foam thickness, incidence angle, and polarization. Experimental results are presented, and then compared to the two-layer foam emission model with the measured foam parameters used as input model parameters. At 37 psu salt water the foam-induced emissivity increase is -0.007 per millimeter of foam thickness (extrapolated to nadir), increasing with increasing incidence angles at vertical polarization, and decreasing with increasing incidence angles at horizontal polarization. | ||||||||
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