Validation of a spectral correction procedure for sun and sky reflections in above-water reflectance measurements

Article English OPEN
Groetsch, Philipp M.M. ; Gege, Peter ; Simis, Stefan G.H. ; Eleveld, Marieke A. ; Peters, Steef W.M. (2017)
  • Publisher: dsfsdf
  • Related identifiers: doi: 10.1364/oe.25.00a742
  • Subject: Institut für Methodik der Fernerkundung | EA0 | Experimentelle Verfahren

A three-component reflectance model (3C) is applied to above-water radiometric measurements to derive remote-sensing reflectance Rrs(l). 3C provides a spectrally resolved offset D(l) to correct for residual sun and sky radiance (Rayleigh- and aerosol-scattered) reflections on the water surface that were not represented by sky radiance measurements. 3C is validated with a data set of matching above- and below-water radiometric measurements collected in the Baltic Sea, and compared against a scalar offset correction D. Correction with D(l) instead of D consistently reduced the (mean normalized root-mean-square) deviation between Rrs(l) and reference reflectances to comparable levels for clear (D: 14.3 +- 2.5 %, D(l): 8.2 +- 1.7 %), partly clouded (D: 15.4 +- 2.1 %, D(l): 6.5 +- 1.4 %), and completely overcast (D: 10.8 +- 1.7 %, D(l): 6.3 +- 1.8 %) sky conditions. The improvement was most pronounced under inhomogeneous sky conditions when measurements of sky radiance tend to be less representative of surface-reflected radiance.Accounting for both sun glint and sky reflections also relaxes constraints on measurement geometry, which was demonstrated based on a semi-continuous daytime data set recorded in an eutrophic freshwater lake in the Netherlands. Rrs(l) that were derived throughout the day varied spectrally by less than 2 % relative standard deviation. Implications on measurement protocols are discussed. An open source software library for processing reflectance measurements was developed and is made publicly available.
  • References (29)
    29 references, page 1 of 3

    9. K. G. Ruddick, V. De Cauwer, Y.-J. Park, and G. Moore, “Seaborne measurements of near infrared water-leaving reflectance: The similarity spectrum for turbid waters,” Limnol. Oceanog. 51, 1167-1179 (2006).

    10. S. G. Simis and J. Olsson, “Unattended processing of shipborne hyperspectral reflectance measurements,” Rem. Sens. Environ. 135, 202-212 (2013).

    11. V. Martinez-Vicente, S. G. H. Simis, R. Alegre, P. E. Land, and S. B. Groom, “Above-water reflectance for the evaluation of adjacency effects in earth observation data: Initial results and methods comparison for near-coastal waters in the western channel, UK,” J. Euro. Opt. Soc. 8, 13060 (2013).

    12. Z. Lee, Y.-h. Ahn, C. Mobley, and R. Arnone, “Removal of surface-reflected light for the measurement of remote-sensing reflectance from an above-surface platform,” Opt. Express 18, 171-182 (2010).

    13. T.-W. Cui, Q.-J. Song, J.-W. Tang, and J. Zhang, “Spectral variability of sea surface skylight reflectance and its effect on ocean color.” Opt. Express 21, 24929-24941 (2013).

    14. L. G. Sokoletsky and F. Shen, “Optical closure for remote-sensing reflectance based on accurate radiative transfer approximations: the case of the Changjiang (Yangtze) River Estuary and its adjacent coastal area, China,” Int. J. Rem. Sens. 35, 4193-4224 (2014).

    15. D. A. Toole, D. A. Siegel, D. W. Menzies, M. J. Neumann, and R. C. Smith, “Remote-sensing reflectance determinations in the coastal ocean environment: impact of instrumental characteristics and environmental variability.” Appl. Opt. 39, 456-469 (2000).

    16. X. Zhang, S. He, A. Shabani, P.-W. Zhai, and K. Du, “Spectral sea surface reflectance of skylight,” Opt. Express 25, A1 (2017).

    17. P. Gege, “The water color simulator WASI: an integrating software tool for analysis and simulation of optical in situ spectra,” Comput. Geosci. 30, 523-532 (2004).

    18. W. Gregg and K. Carder, “A simple spectral solar irradiance model for cloudless maritime atmospheres,” Limonol. Oceanog. 35, 1657-1675 (1990).

  • Metrics
    views in OpenAIRE
    views in local repository
    downloads in local repository

    The information is available from the following content providers:

    From Number Of Views Number Of Downloads
    Plymouth Marine Science Electronic Archive (PlyMEA) - IRUS-UK 0 20
Share - Bookmark