Assessing uncertainties in scattering correction algorithms for reflective tube absorption measurements made with a WET Labs ac-9

Stockley, Nicole D. and Röttgers, Rüdiger and McKee, David and Lefering, Ina and Sullivan, James M. and Twardowski, Michael S. (2017) Assessing uncertainties in scattering correction algorithms for reflective tube absorption measurements made with a WET Labs ac-9. Optics Express, 25 (24). A1139-A1153. ISSN 1094-4087 (https://doi.org/10.1364/OE.25.0A1139)

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Abstract

In situ absorption measurements collected with a WET Labs ac-9 employing a reflective tube approach were scatter corrected using several possible methods and compared to reference measurements made by a PSICAM to assess performance. Overall, two correction methods performed best for the stations sampled: one using an empirical relationship between the ac-9 and PSICAM to derive the scattering error (ε) in the nearinfrared (NIR), and one where ε was independently derived from concurrent measurements of the volume scattering function (VSF). Application of the VSF-based method may be more universally applicable, although difficult to routinely apply because of the lack of commercially available VSF instrumentation. The performance of the empirical approach is encouraging as it relies only on the ac meter measurement and may be readily applied to historical data, although there are inevitably some inherent assumptions about particle composition that hinder universal applicability. For even the best performing methods, residual errors of 20% or more were commonly observed for many water types. For clear ocean waters, a conventional baseline subtraction with the assumption of negligible near-IR absorption performed as well or better than the above methods because propagated uncertainties were lower than observed with the proportional method.

  • Item type:Article
    ID code:62364
    Dates:
    Date
    Event
    10 November 2017
    Published
    31 October 2017
    Accepted
    Notes:© 2017 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.
    Subjects:Science > Physics > Optics. Light
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:15 Nov 2017 12:18
    Last modified:08 Apr 2024 23:41
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/62364
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