Estimations of inherent optical properties of the St. Lawrence estuary using airborne hyperspectral data.

摘要

For this study, the CAM5S atmospheric correction procedure was applied to low altitude (600 m.) water scenes to retrieve above water reflectance. This remote sensing reflectance (R_rs) was then interpreted in terms of its components: the sky and the sun glint component and the subsurface water volume reflectance R_rs w. Using stations with coincident hyperspectral airborne sensor (CASI) and ship data the algorithms for separating, R _rsw from the surface components are evaluated. The next step was to estimate bulk water optical properties and compare these to in-situ measurements. The backscatter to absorption ratio (b _b/a) was estimated from calculated subsurface volume reflectances via the model of Jerome et al (1995). Validation comparisons are made with values derived from in-water data.; These estimates of intrinsic (bulk) optical parameters are then used to establish a water type classification, differentiating Case 1 from Case 2 waters, as well as those transitional ones. A three-wavelength (437, 565, 671 nm) relationship is set up between the b_b/ a ratios that allow the determination of the principal water component present in the medium, and consequently, the water type characteristic of each of the stations under study, plus variations along transect lines. (Abstract shortened by UMI.)