A review of protocols for Fiducial Reference Measurements of downwelling irradiance for the validation of satellite remote sensing data over water

Kevin G. Ruddick, Kenneth Voss, Andrew C. Banks, Emmanuel Boss, Alexandre Castagna, Robert Frouin, Martin Hieronymi, Cedric Jamet, B. Carol Johnson, Joel Kuusk, Zhongping Lee, Michael Ondrusek, Viktor Vabson, Riho Vendt

Research output: Contribution to journalReview article

5 Scopus citations

Abstract

This paper reviews the state of the art of protocols for the measurement of downwelling irradiance in the context of Fiducial Reference Measurements (FRM) of water reflectance for satellite validation. The measurement of water reflectance requires the measurement of water-leaving radiance and downwelling irradiance just above water. For the latter, there are four generic families of method, using: (1) an above-water upward-pointing irradiance sensor; (2) an above-water downward-pointing radiance sensor and a reflective plaque; (3) a Sun-pointing radiance sensor (sunphotometer); or (4) an underwater upward-pointing irradiance sensor deployed at different depths. Each method-except for the fourth, which is considered obsolete for the measurement of above-water downwelling irradiance-is described generically in the FRM context with reference to the measurement equation, documented implementations, and the intra-method diversity of deployment platform and practice. Ideal measurement conditions are stated, practical recommendations are provided on best practice, and guidelines for estimating the measurement uncertainty are provided for each protocol-related component of the measurement uncertainty budget. The state of the art for the measurement of downwelling irradiance is summarized, future perspectives are outlined, and key debates such as the use of reflectance plaques with calibrated or uncalibrated radiometers are presented. This review is based on the practice and studies of the aquatic optics community and the validation of water reflectance, but is also relevant to land radiation monitoring and the validation of satellite-derived land surface reflectance.

Original languageEnglish (US)
Article number1742
JournalRemote Sensing
Volume11
Issue number15
DOIs
StatePublished - Aug 1 2019

Keywords

  • Downwelling irradiance
  • Fiducial Reference Measurements
  • Satellite validation
  • Water reflectance

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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    Ruddick, K. G., Voss, K., Banks, A. C., Boss, E., Castagna, A., Frouin, R., Hieronymi, M., Jamet, C., Johnson, B. C., Kuusk, J., Lee, Z., Ondrusek, M., Vabson, V., & Vendt, R. (2019). A review of protocols for Fiducial Reference Measurements of downwelling irradiance for the validation of satellite remote sensing data over water. Remote Sensing, 11(15), [1742]. https://doi.org/10.3390/rs11151742