DocumentCode :
3595788
Title :
Field studies on the action of rain on the radar backscattering from wind-roughened water surfaces
Author :
Braun, Nicole ; Gade, Martin
Author_Institution :
Inst. fur Kustenforschung, GKSS-Forschungszentrum, Geesthacht, Germany
Volume :
4
fYear :
2003
Firstpage :
2248
Abstract :
In order to gain further insight into the radar backscattering from rain-and wind-roughened water surfaces, we performed field experiments at the mouth of the river Elbe in the German Bight. The backscattered radar power from the water surface was measured at different wind speeds, wind directions, and rain rates, as well as at different radar frequencies, polarizations, and incidence angles. Our results show that the dominant scattering mechanism at VV-polarization is Bragg scattering which shows a strong dependence on the Bragg wavelength. The enhancement and reduction of the surface roughness by splash products and sub-surface phenomena, respectively, result in a transition wavenumber between enhancement of the radar backscattering (due to additional surface roughness) and its reduction (due to wave damping) of about 100 rad/m. We hypothesize that this transition wavenumber depends on the drop-size distribution of the rain. Taking into consideration the different dependencies on rain rate of the radar backscatter at different frequencies and polarizations, we suggest a method to estimate rain rates by calculating the ratio of the radar cross-sections at L band, VV-polarization and at C band, HV-polarization. Provided an availability of synthetic aperture radar (SAR) data at the respective frequency/polarization combinations, this method will allow for investigating the nature of small-scale (convective) rain events over the ocean by analyzing multi-frequency/multi-polarization SAR images.
Keywords :
backscatter; oceanographic regions; oceanographic techniques; rain; remote sensing by radar; synthetic aperture radar; wind; Bragg scattering; Elbe river; German Bight; HV polarization; VV polarization; dominant scattering mechanism; multifrequency-multipolarization SAR images; radar backscattering; radar frequencies; rain rate; rain roughened water surfaces; surface roughness; synthetic aperture radar; transition wavenumber; wind roughened water surfaces; Backscatter; Frequency; Polarization; Radar measurements; Radar scattering; Rain; Rough surfaces; Sea surface; Surface waves; Wind speed;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2003. IGARSS '03. Proceedings. 2003 IEEE International
Print_ISBN :
0-7803-7929-2
Type :
conf
DOI :
10.1109/IGARSS.2003.1294404
Filename :
1294404
Link To Document :
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