Advancing two-component partitioning of light scattering in Cayuga Lake, New York.

The particulate scattering and backscattering coefficients ( bp and bbp) were partitioned into the additive contributions of minerogenic ( bm and bb,m) and organic ( bo and bb,o) components for nearshore and pelagic areas of Cayuga Lake, New York, over a 7 month period in 2013. The analysis was based on paired measurements of (1) bulk bp and bbp, (2) light-scattering properties of mineral particles, with an individual particle analysis (IPA) technique, and (3) concentrations of chlorophyll a ([Chl]) and particulate organic carbon (POC), as two indices to quantify organic particle scattering. bm and bb,m were estimated through Mie theory calculations with IPA results as inputs. bo and bb,o were estimated with both system-specific and oceanic bio-optical models parameterized on [Chl] or POC. POC performed better than [Chl] as the index for both bo and bb,o. The averages of the ratios ( bm + bo) : bp and ( bb,m + bb,o) : bbp at 660 nm, were 1.02 and 1.03, respectively; the average relative errors were 18.2% and 15.6%. Multiple empirical bio-optical models developed for Case 1 oceanic waters (for bo and bb,o estimates) approached the closure performance of the system-specific relationships. In addition to systematically accounting for more bbp than bp, terrigenous minerogenic particles made greater contributions to both bp and bbp in the nearshore area proximate to tributary inputs than in pelagic waters. A strong positive dependency of the backscattering ratio ( bbp : bp) on the bm : bp ratio was observed for both nearshore and pelagic areas. [ABSTRACT FROM AUTHOR]