Multi-method approach to quantify uncertainties in the measurements of light absorption by particles

Through technological and research advances, numerous methods and protocols have emerged to estimate spectral absorption of light by particles, a_p, in an aquatic medium. However, the level of agreement among measurements remains elusive. We employed a multi-method approach to estimate the measurement precision of measuring optical density of particles on a filter pad using two common spectrophotometric methods, and the determination precision, or uncertainty, of the computational techniques for estimating a_p for six ocean color wavelengths (412, 443, 490, 510, 555, 670 nm). The optical densities measured with the two methods exhibited a significant, positive correlation. Optical density measurement precision ranged from 0.061%-63% and exhibited a significant, positive correlation. Multi-method uncertainty ranged from 7.48%-119%. Values of a_p at 555 nm and 670 nm exhibited the highest values of uncertainty. Poor performance of modeled a_p compared to determined a_p suggest uncertainties are propagated into bio-optical algorithms.