Optical Closure of Apparent Optical Properties in Coastal Waters off Goa

Talaulikar, Madhubala; Suresh, T.; Desa, E.; Inamdar, Arun B.

doi:10.1007/s12524-014-0393-5

Cited by 2 publications

(2 citation statements)

References 27 publications

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“…Their work also highlighted the accuracy of radiance measurements (~25% suggested for in situ determinations) as a major source of uncertainty in optical closure tests. Several studies have since investigated the effect of particle characteristics, such as the slope of the particle size distribution and shape of the VSF, on optical closure [30][31][32][33][34]. Bugarelli et al [35], for example, identified the limitation of using an average Petzold phase function [36] for their case studies and additionally observed high sensitivity of modelled in-water radiometric profiles to variations in the bottom reflectance.…”

Section: Introductionmentioning

confidence: 99%

Optical closure in marine waters from in situ inherent optical property measurements

Lefering¹,

Bengil²,

Trees³

et al. 2016

Opt. Express

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Optical closure using radiative transfer simulations can be used to determine the consistency of in situ measurements of inherent optical properties (IOPs) and radiometry. Three scattering corrections are applied to in situ absorption and attenuation profile data for a range of coastal and oceanic waters, but are found to have only very limited impact on subsequent closure attempts for these stations. Best-fit regressions on log-transformed measured and modelled downwards irradiance, Ed, and upwards radiance, Lu, profiles have median slopes between 0.92 - 1.24, revealing a tendency to underestimate Ed and Lu with depth. This is only partly explained by non-inclusion of fluorescence emission from CDOM and chlorophyll in the simulations. There are several stations where multiple volume scattering function related data processing steps perform poorly which suggests the potential existence of unresolved features in the modelling of the angular distribution of scattered photons. General optical closure therefore remains problematic, even though there are many cases in the data set where the match between measured and modelled radiometric data is within 25% RMS%E. These results are significant for applications that rely on optical closure e.g. assimilating ocean colour data into coupled physical-ecosystem models.

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Section: Introductionmentioning

confidence: 99%

Optical closure in marine waters from in situ inherent optical property measurements

Lefering¹,

Bengil²,

Trees³

et al. 2016

Opt. Express

View full text Add to dashboard Cite

show abstract

“…According to Xiong et al, (26) approximately 71% of the uncertainty in R rs attributed to the shape of the VSF can be explained by the backscattering probability of particles (B p ), approximately 90% by the scattering phase function, and approximately 97% by the conversion coefficient χ p for particles. Additionally, the applicability of analytical functions such as the Fournier-Forand function in highly turbid water is known to be uncertain, (27,28) and further research on its applicability is needed in the future.…”

Section: Uncertainties In Radiative Transfer Calculationsmentioning

confidence: 99%