Spectra of particulate backscattering in natural waters.
Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (b(b)) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorption features attributable to several phytoplankton pigments (Chlorophyll a, b, c, and Carotenoids). The backscattering shows only weak spectral features and can be well represented by a power-law variation with wavelength (lambda): b(b) approximately lambda(-n), where n is a constant between 0.4 and 1.0. However, the weak spectral features in b(b)b suggest that it is depressed in spectral regions of strong particle absorption. The applicability of the present inverse radiative transfer algorithm, which omits the influence of Raman scattering, is limited to lambda < 490 nm in oligotrophic waters and lambda < 575 nm in mesotrophic waters.
Gordon
Howard R
HR
Department of Physics, University of Miami, Coral Gables, FL 33124, USA. hgordon@miami.edu
Lewis
Marlon R
MR
McLean
Scott D
SD
Twardowski
Michael S
MS
Freeman
Scott A
SA
Voss
Kenneth J
KJ
Boynton
G Chris
GC
D008027:Light; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry*; D010839:Phytoplankton / Q000302:isolation & purification* / Q000502:physiology*; D012031:Refractometry / Q000379:methods*; D045483:Rivers / Q000737:chemistry*; D012542:Scattering, Radiation; D013057:Spectrum Analysis / Q000379:methods*
D052638:Particulate Matter