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Title: Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR

Abstract

Wetlands continue to be under threat, and there is a major need for mapping and monitoring wetlands for better management and protection of these sensitive areas. Only a few studies have been published on wetland characterization using polarimetric synthetic aperture radars (SARs). The most successful results have been obtained using the phase difference between HH and VV polarizations, phi{sub HH} - phi{sub VV}, which has shown promise for separating flooded wetland classes. Recently, we have introduced a new decomposition, the Touzi decomposition, which describes target scattering type in terms of a complex entity, the symmetric scattering type. Huynen's target helicity is used to assess the symmetric nature of target scattering. In this paper, the new complex-scattering-type parameters, the magnitude alphas and phase Phi{sub alpha} s, are investigated for wetland characterization. The use of the dominant-scattering-type phase Phi{sub alpha} s makes it possible to discriminate shrub bogs from poor (sedge or shrub) fens. These two classes cannot be separated using phi{sub HH} - phi{sub VV}, or the radiometric scattering information provided by alphas, the Cloude alpha, the entropy H, and the multipolarization HH-HV-VV channels. phi{sub alpha} s, which cannot detect deep (45 cm below the peat surface) water flow in amore » bog, is more sensitive to the shallower (10-20-cm) fen beneath water, and this makes possible the separation of poor fens from shrub bogs. Phi{sub alpha} s also permits the discrimination of conifer-dominated treed bog from upland deciduous forest under leafy conditions. Target helicity information is exploited to introduce a new parameter, the target asymmetry. The latter is shown very promising for detection of forest changes between leafy and no-leaf conditions. The analysis of low-entropy marsh scattering showed that both the scattering-type magnitude and phas- - e alphas and Phi{sub alpha} s, respectively, as well as the maximum polarization intensity of the dominant scattering m, are needed for a better understanding of marsh complex scattering mechanisms. The unique information provided by the new roll-invariant decomposition parameters are demonstrated using repeat-pass Convair-580 polarimetric C-band SAR data collected in June and October 1995 over the RAMSAR Mer Bleue wetland site near Ottawa (Canada).« less

Authors:
 [1];  [2];  [2]
  1. Argonne National Laboratory (ANL)
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1008847
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
IEEE Tranactions on Geoscience and Remote Sensing
Additional Journal Information:
Journal Volume: 47; Journal Issue: 9; Journal ID: ISSN 0196--2892
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; APERTURES; ASYMMETRY; DETECTION; ENTROPY; FORESTS; HELICITY; MANAGEMENT; MONITORING; PEAT; POLARIZATION; SCATTERING; SHRUBS; TARGETS; WATER; WETLANDS

Citation Formats

Touzi, R, Deschamps, Mireille C, and Rother, Gernot. Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR. United States: N. p., 2009. Web. doi:10.1109/TGRS.2009.2018626.
Touzi, R, Deschamps, Mireille C, & Rother, Gernot. Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR. United States. doi:10.1109/TGRS.2009.2018626.
Touzi, R, Deschamps, Mireille C, and Rother, Gernot. Tue . "Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR". United States. doi:10.1109/TGRS.2009.2018626.
@article{osti_1008847,
title = {Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR},
author = {Touzi, R and Deschamps, Mireille C and Rother, Gernot},
abstractNote = {Wetlands continue to be under threat, and there is a major need for mapping and monitoring wetlands for better management and protection of these sensitive areas. Only a few studies have been published on wetland characterization using polarimetric synthetic aperture radars (SARs). The most successful results have been obtained using the phase difference between HH and VV polarizations, phi{sub HH} - phi{sub VV}, which has shown promise for separating flooded wetland classes. Recently, we have introduced a new decomposition, the Touzi decomposition, which describes target scattering type in terms of a complex entity, the symmetric scattering type. Huynen's target helicity is used to assess the symmetric nature of target scattering. In this paper, the new complex-scattering-type parameters, the magnitude alphas and phase Phi{sub alpha} s, are investigated for wetland characterization. The use of the dominant-scattering-type phase Phi{sub alpha} s makes it possible to discriminate shrub bogs from poor (sedge or shrub) fens. These two classes cannot be separated using phi{sub HH} - phi{sub VV}, or the radiometric scattering information provided by alphas, the Cloude alpha, the entropy H, and the multipolarization HH-HV-VV channels. phi{sub alpha} s, which cannot detect deep (45 cm below the peat surface) water flow in a bog, is more sensitive to the shallower (10-20-cm) fen beneath water, and this makes possible the separation of poor fens from shrub bogs. Phi{sub alpha} s also permits the discrimination of conifer-dominated treed bog from upland deciduous forest under leafy conditions. Target helicity information is exploited to introduce a new parameter, the target asymmetry. The latter is shown very promising for detection of forest changes between leafy and no-leaf conditions. The analysis of low-entropy marsh scattering showed that both the scattering-type magnitude and phas- - e alphas and Phi{sub alpha} s, respectively, as well as the maximum polarization intensity of the dominant scattering m, are needed for a better understanding of marsh complex scattering mechanisms. The unique information provided by the new roll-invariant decomposition parameters are demonstrated using repeat-pass Convair-580 polarimetric C-band SAR data collected in June and October 1995 over the RAMSAR Mer Bleue wetland site near Ottawa (Canada).},
doi = {10.1109/TGRS.2009.2018626},
journal = {IEEE Tranactions on Geoscience and Remote Sensing},
issn = {0196--2892},
number = 9,
volume = 47,
place = {United States},
year = {2009},
month = {9}
}