Oral Session 10 | Thursday, October 6, 15:00–15:20 | Abstract 483

A model for partitioning the non-algal absorption coefficient of seawater into contributions of non-algal particulate matter and CDOM in the ultraviolet and visible spectral region

One aim of ocean color remote sensing is to derive the water-constituent absorption coefficients of phytoplankton, aph, non-algal particles, ad, and chromophoric dissolved organic matter (CDOM), ag. The coefficients ad and ag are important for underwater propagation of ultraviolet (UV) radiation as they increase approximately exponentially from the visible (VIS) towards the UV. The spectral similarities between ad and ag create challenges when applying modeling approaches to separate these coefficients from their sum, adg. We describe refinements to a recently published model (ADG) that partitions adg into ad and ag in the VIS, which include extension of the model output to the UV. These refinements employ a newly assembled field dataset of ad and ag measurements subjected to a number of strict methodological and data quality control inclusion and exclusion criteria. Analysis of this dataset led to the creation of new libraries of characteristic spectral shape functions of ad and ag, an essential component of the ADG model. We examined two implementations of the model to estimate ad and ag from 350 to 700 nm: the first determines solutions by utilizing a new UV-VIS spectral library, and the second determines solutions by utilizing a new VIS spectral library coupled with an extrapolating model to extend output from the VIS to the UV. We evaluate the performance of these model implementations and provide a comparison with the original ADG model that utilized a VIS spectral library developed from a dataset with less strict methodological criteria for ad and ag determinations.

*Matthew Kehrli, Scripps Institution of Oceanography, UCSD, 0000-0003-1268-676X

Dariusz Stramski, Scripps Institution of Oceanography, UCSD, 0000-0002-8518-072X

Rick Reynolds, Scripps Institution of Oceanography, UCSD, 0000-0002-1579-3600

Ishan Joshi, Scripps Institution of Oceanography, UCSD, 0000-0001-7710-0059

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