Depth-variant spectral characteristics of submersed aquatic vegetation detected by Landsat 7 ETM+
Abstract:Spectral variations along depth profiles were compared using two subsets of a Landsat 7 Enhanced Thematic Mapper (ETM+) scene to test the difference between submersed aquatic vegetation (SAV) and non-vegetated bare substrate in their depth-induced spectral variation. Field-surveyed water depth and SAV cover along transects were overlaid with the satellite image of Lake Pontchartrain, LA, USA. Digital numbers on the survey transects for each band and for band ratios were correlated with depth and vegetation cover. Band 1/band 3 correlated well with depth in both SAV and bare substrates, indicating that this ratio least reflects the effect of SAV. The ratio of bands 2 and 1 correlated best with vegetation cover within the shallow estuarine waters. Correlations between depth and the ratio of band 2/band3 showed contrasting results between the two substrate types (SAV and bare), suggesting that the depth-induced variations in the band ratio can be used as indicators of SAV.
Document Type: Research Article
Affiliations: Department of Biology, Jackson State University, Jackson, USA
Publication date: January 1, 2007