Multi-temporal, multi-frequency, and multi-polarization coherence and SAR backscatter analysis of wetlands

verfasst von

Fariba Mohammadimanesh, Bahram Salehi, Masoud Mahdianpari, Brian Brisco, Mahdi Motagh

Abstract

Despite recent research into the Interferometric Synthetic Aperture Radar (InSAR) technique for wetland mapping worldwide, its capability has not yet been thoroughly investigated for Canadian wetland ecosystems. Accordingly, this study statistically analysed interferometric coherence and SAR backscatter variation in a study area located on the Avalon Peninsula, Newfoundland and Labrador, Canada, consisting of various wetland classes, including bog, fen, marsh, swamp, and shallow-water. Specifically, multi-temporal L-band ALOS PALSAR-1, C-band RADARSAT-2, and X-band TerraSAR-X data were used to investigate the effect of SAR frequency and polarization, as well as temporal baselines on the coherence degree in the various wetland classes. SAR backscatter and coherence maps were also used as input features into an object-based Random Forest classification scheme to examine the contribution of these features to the overall classification accuracy. Our findings suggested that the temporal baseline was the most influential factor for coherence maintenance in herbaceous wetlands, especially for shorter wavelengths. In general, coherence was the highest in L-band and intermediate/low for both X- and C-band, depending on the wetland classes and temporal baseline. The Wilcoxon rank sum test at the 5% significance level found significant difference (P-value < 0.05) between the mean values of HH/HV coherence at the peak of growing season. The test also suggested that L-band intensity and X-band coherence observations were advantageous to discriminate complex wetland classes. Notably, an overall classification accuracy of 74.33% was attained for land cover classification by synergistic use of both SAR backscatter and interferometric coherence. Thus, the results of this study confirmed the potential of incorporating SAR and InSAR features for mapping Canadian wetlands and those elsewhere in the world with similar ecological characteristics.

Organisationseinheit(en)

Institut für Photogrammetrie und Geoinformation

Externe Organisation(en)

Memorial University of Newfoundland
Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ)
Canada Center for Mapping and Earth Observation (CCMEO)

Typ

Artikel

Journal

ISPRS Journal of Photogrammetry and Remote Sensing

Band

142

Seiten

78-93

Anzahl der Seiten

16

ISSN

0924-2716

Publikationsdatum

08.2018

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Atom- und Molekularphysik sowie Optik, Ingenieurwesen (sonstige), Angewandte Informatik, Computer in den Geowissenschaften

Ziele für nachhaltige Entwicklung

SDG 15 – Lebensraum Land

Elektronische Version(en)

https://doi.org/10.1016/j.isprsjprs.2018.05.009 (Zugang: Geschlossen)