On the Bragg Scattering Observed in L-Band Synthetic Aperture Radar Images of Flooded Rice Fields

Kazuo OUCHI
Haipeng WANG
Naoki ISHITSUKA
Genya SAITO
Kentaro MOHRI

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B    No.8    pp.2218-2225
Publication Date: 2006/08/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.8.2218
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Sensing
Keyword: 
synthetic aperture radar (SAR),  Bragg scattering,  rice plants,  JERS-1 SAR,  Pi-SAR,  

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Summary: 
This article presents the analysis of the Bragg scattering phenomenon which has been observed in the images of machine-planted rice paddies acquired by the JERS-1 L-band synthetic aperture radar (SAR). The simultaneous measurements of rice plants were made at the SAR data acquisition times. Large differences of 20-25 dB in image intensity between the transplanting and ripening stages are found to be dependent on the planting direction and bunch separation. This selective image enhancement is a result of the Bragg resonance backscatter due to the double-bounce of incident L-band microwave between the flooded water surface and periodically planted bunches of rice plants. Support for the idea of double-bounce scattering is provided by the decomposition analysis of L-band and X-band polarimetric Pi-SAR data; and a simple numerical simulation based on the physical optics model shows fairly good agreement with the JERS-1 SAR data. The results presented in this paper is mainly of academic interest, but a suggestion can be made on the selection of suitable microwave band for monitoring rice fields.