Absorption and scattering coefficients in Irondequoit Bay1

Abstract

Profiles of scalar, downwelling, upwelling, and spectral irradiance were measured on 37 dates in 1982–1983. Values of the attenuation coefficient K were 0.8–1.2 m⁻¹, and the reflectance R was 0.03–0.06. By Kirk’s method, the absorption and scattering coefficients a and b were found to be 0.44–0.83 and 1.8−5.0 m⁻¹. Also measured were turbidity, chlorophyll, and absorption spectra of dissolved yellow substances and of particles. Independent estimates of a, as the sum of absorption components, were in reasonable agreement with values obtained by Kirk’s method. For particles, the average value of the Chl‐specific absorption coefficient k_a was ~0.008–0.010 m² mg⁻¹ Chl. Values of the Chl‐specific scattering coefficient k_b were usually ~0.05–0.10 m² mg⁻¹ Chl; values were higher (~0.12) when gas‐vacuolate cyanobacteria were present.