Estimation of absorption and backscattering coefficients from in situ radiometric measurements: theory and validation in case 2 waters

D.J.C. McKee, A. Cunningham, S.E. Craig

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

A model that relates the coefficients of absorption (a) and backscattering (bb) to diffuse attenuation (Kd), radiance reflectance (RL), and the mean cosine for downward irradiance (μd) is presented. Radiance transfer simulations are used to verify the physical validity of the model for a wide range of water column conditions. Analysis of these radiance transfer simulations suggests that absorption and backscattering can be estimated with average errors of 1% and 3%, respectively, if the value of μd is known with depth. If the input data set is restricted to variables that can be derived from measurements of upward radiance (Lu) and downward irradiance (Ed), it is necessary to use approximate values of μd. Examination of three different approximation schemes for μd shows that the average error for estimating a and bb increases to ~13%. We tested the model by using measurements of Lu and Ed collected from case II waters off the west coast of Scotland. The resulting estimates of a and bb were compared with independent in situ measurements of these parameters. Average errors for the data set were of the order of 10% for both absorption and backscattering.
LanguageEnglish
Pages2804-2810
Number of pages7
JournalApplied Optics
Volume42
Issue number15
DOIs
Publication statusPublished - 2003

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radiance
backscattering
absorptivity
coefficients
irradiance
water
Scotland
in situ measurement
coasts
estimating
simulation
examination
attenuation
reflectance
estimates
approximation

Keywords

  • absorption
  • backscattering
  • radiometric measurements

Cite this

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title = "Estimation of absorption and backscattering coefficients from in situ radiometric measurements: theory and validation in case 2 waters",
abstract = "A model that relates the coefficients of absorption (a) and backscattering (bb) to diffuse attenuation (Kd), radiance reflectance (RL), and the mean cosine for downward irradiance (μd) is presented. Radiance transfer simulations are used to verify the physical validity of the model for a wide range of water column conditions. Analysis of these radiance transfer simulations suggests that absorption and backscattering can be estimated with average errors of 1{\%} and 3{\%}, respectively, if the value of μd is known with depth. If the input data set is restricted to variables that can be derived from measurements of upward radiance (Lu) and downward irradiance (Ed), it is necessary to use approximate values of μd. Examination of three different approximation schemes for μd shows that the average error for estimating a and bb increases to ~13{\%}. We tested the model by using measurements of Lu and Ed collected from case II waters off the west coast of Scotland. The resulting estimates of a and bb were compared with independent in situ measurements of these parameters. Average errors for the data set were of the order of 10{\%} for both absorption and backscattering.",
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Estimation of absorption and backscattering coefficients from in situ radiometric measurements: theory and validation in case 2 waters. / McKee, D.J.C.; Cunningham, A.; Craig, S.E.

In: Applied Optics, Vol. 42, No. 15, 2003, p. 2804-2810.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Estimation of absorption and backscattering coefficients from in situ radiometric measurements: theory and validation in case 2 waters

AU - McKee, D.J.C.

AU - Cunningham, A.

AU - Craig, S.E.

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N2 - A model that relates the coefficients of absorption (a) and backscattering (bb) to diffuse attenuation (Kd), radiance reflectance (RL), and the mean cosine for downward irradiance (μd) is presented. Radiance transfer simulations are used to verify the physical validity of the model for a wide range of water column conditions. Analysis of these radiance transfer simulations suggests that absorption and backscattering can be estimated with average errors of 1% and 3%, respectively, if the value of μd is known with depth. If the input data set is restricted to variables that can be derived from measurements of upward radiance (Lu) and downward irradiance (Ed), it is necessary to use approximate values of μd. Examination of three different approximation schemes for μd shows that the average error for estimating a and bb increases to ~13%. We tested the model by using measurements of Lu and Ed collected from case II waters off the west coast of Scotland. The resulting estimates of a and bb were compared with independent in situ measurements of these parameters. Average errors for the data set were of the order of 10% for both absorption and backscattering.

AB - A model that relates the coefficients of absorption (a) and backscattering (bb) to diffuse attenuation (Kd), radiance reflectance (RL), and the mean cosine for downward irradiance (μd) is presented. Radiance transfer simulations are used to verify the physical validity of the model for a wide range of water column conditions. Analysis of these radiance transfer simulations suggests that absorption and backscattering can be estimated with average errors of 1% and 3%, respectively, if the value of μd is known with depth. If the input data set is restricted to variables that can be derived from measurements of upward radiance (Lu) and downward irradiance (Ed), it is necessary to use approximate values of μd. Examination of three different approximation schemes for μd shows that the average error for estimating a and bb increases to ~13%. We tested the model by using measurements of Lu and Ed collected from case II waters off the west coast of Scotland. The resulting estimates of a and bb were compared with independent in situ measurements of these parameters. Average errors for the data set were of the order of 10% for both absorption and backscattering.

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KW - backscattering

KW - radiometric measurements

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