Assessing flooding and vegetation structure in forested wetlands using radarsat SAR imagery

Philip A. Townsend, Jane R. Foster

Research output: Contribution to conferencePaper

5 Scopus citations

Abstract

We used 32 Radarsat SAR images collected between 1996 and 2001 over the Roanoke River floodplain, North Carolina (USA), to assess the utility of C-HH Radarsat SAR for operationally mapping flooding beneath forest canopies. Our objective was to test the sensitivity of standard-beam Radarsat to flooded forests under leaf-on and leaf-off conditions, and at multiple incidence angles (ranging from 10-46°). We found that winter (leaf-off images) could be used to accurately map flooding (> 95% accuracy) regardless of incidence angle. Mapping accuracy was acceptable for leaf-on images (> 85%) but was nevertheless significantly lower than for leaf-off images. Images at shallow incidence angles (e.g. S6 mode, 41-46°) were especially affected by speckle in the interpretations, whereas images acquired at very steep incidence angles (extended low beam, 10-23°) exhibited a substantial amount of geometric feature displacement that limited their utility for practical applications. For mature forests, forest structure (independent of leaf-on or leaf-off status) did not appear to affect the ability to map flooding; however, separate interpretations were required to delineate flooding in very young, dense successional stands (< 15 years). When controlling for flooding status, we found that Radarsat images were sensitive (in a statistical sense) to some components of forest structure (basal area, canopy height, crown depth), especially if both leaf-on and leaf-off images and images acquired at multiple angles were used for the analysis.

Original languageEnglish (US)
Pages1171-1173
Number of pages3
StatePublished - Jan 1 2002
Event2002 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2002) - Toronto, Ont., Canada
Duration: Jun 24 2002Jun 28 2002

Other

Other2002 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2002)
CountryCanada
CityToronto, Ont.
Period6/24/026/28/02

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    Townsend, P. A., & Foster, J. R. (2002). Assessing flooding and vegetation structure in forested wetlands using radarsat SAR imagery. 1171-1173. Paper presented at 2002 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2002), Toronto, Ont., Canada.