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 language||English (US)|
|Number of pages||3|
|State||Published - Jan 1 2002|
|Event||2002 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2002) - Toronto, Ont., Canada|
Duration: Jun 24 2002 → Jun 28 2002
|Other||2002 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2002)|
|Period||6/24/02 → 6/28/02|