Evaluation of the Quasi-Analytical Algorithm for estimating the inherent optical properties of seawater from ocean color: Comparison of Arctic and lower-latitude waters

Academic Article


  • We evaluated the performance of the Quasi-Analytical Algorithm (QAA, v5 with modifications) for deriving the spectral total absorption, a(λ), and backscattering, b (λ), coefficients of seawater and partitioning of a(λ) into phytoplankton and non-phytoplankton components from input spectrum of remote-sensing reflectance, R (λ), with field data collected in the Arctic and lower-latitude open waters from the Atlantic and Pacific Oceans. The systematic error based on median ratio between QAA-derived and measured a(λ) varied from about 1% to ±. 10% depending on light wavelength and the oceanic region. The QAA typically overestimated b (λ) from 3% to 14% compared with field measurements. These results were obtained with a correction for Raman-scattering contribution to R and separate parameterization of molecular and particulate backscattering in the R vs. b /. a relationship. Without these features the earlier versions of the QAA can overestimate b (λ) by as much as 35% in clear waters. The use of pure seawater backscattering coefficients accounting for water temperature and salinity improved the accuracy of QAA-derived a(λ) in Arctic waters. The absorption-partitioning component of the QAA significantly underestimated phytoplankton absorption and overestimated non-phytoplankton absorption in both Arctic and lower-latitude waters. b rs b rs rs b b
  • Digital Object Identifier (doi)

    Author List

  • Zheng G; Stramski D; Reynolds RA
  • Start Page

  • 194
  • End Page

  • 209
  • Volume

  • 155