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Title: SeaWiFS long-term solar diffuser reflectance and sensor noise analyses

Abstract

The NASA Ocean Biology Processing Group's Calibration and Validation(Cal/Val) team has undertaken an analysis of the mission-long Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)solar calibration time series to assess the long-term degradation of the solar diffuser reflectance over 9 years on orbit. The SeaWiFS diffuser is an aluminum plate coated with YB71 paint. The bidirectional reflectance distribution function of the diffuser was not fully characterized before launch,so the Cal/Val team has implemented a regression of the solar incidence angles and the drift in the node of the satellite's orbit against the diffuser time series to correct for solar incidence angle effects. An exponential function with a time constant of 200 days yields the best fit to the diffuser time series.The decrease in diffuser reflectance over the mission is wavelength dependent,ranging from 9% in the blue(412 nm) to 5% in the red and near infrared(670-865 nm). The Cal/Val team has developed a methodology for computing the signal-to-noise ratio (SNR) for SeaWiFS on orbit from the diffuser time series corrected for both the varying solar incidence angles and the diffuser reflectance degradation. A sensor noise model is used to compare on-orbit SNRs computed for radiances reflected from the diffuser with prelaunch SNRs measured atmore » typical radiances specified for the instrument. To within the uncertainties in the measurements, the SNRs for SeaWiFS have not changed over the mission. The on-orbit performance of the SeaWiFS solar diffuser should offer insight into the long-term on-orbit performance of solar diffusers on other instruments, such as the Moderate-Resolution Imaging Spectrometer [currently flying on the Earth Observing System (EOS) Terra and Aqua satellites], the Visible and Infrared Radiometer Suite [scheduled to fly on the NASA National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Project (NPP) satellites] and the Advanced Baseline Imager [scheduled to fly on the National Oceanic and Atmospheric Administration Geostationary Environmental Operational Satellite Series R (GOES-R) satellites].« less

Authors:
; ; ;
Publication Date:
OSTI Identifier:
20929603
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Optics; Journal Volume: 46; Journal Issue: 5; Other Information: DOI: 10.1364/AO.46.000762; (c) 2007 Optical Society of America; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM; CALIBRATION; DIFFUSERS; DISTRIBUTION FUNCTIONS; INCIDENCE ANGLE; NASA; NOISE; OCEANOGRAPHY; OPTICS; ORBITS; PAINTS; PERFORMANCE; RADIOMETERS; REMOTE SENSING; SATELLITES; SEAS; SIGNAL-TO-NOISE RATIO; SPECTROMETERS; US NOAA; VALIDATION

Citation Formats

Eplee, Robert E. Jr., Patt, Frederick S., Barnes, Robert A., and McClain, Charles R. SeaWiFS long-term solar diffuser reflectance and sensor noise analyses. United States: N. p., 2007. Web. doi:10.1364/AO.46.000762.
Eplee, Robert E. Jr., Patt, Frederick S., Barnes, Robert A., & McClain, Charles R. SeaWiFS long-term solar diffuser reflectance and sensor noise analyses. United States. doi:10.1364/AO.46.000762.
Eplee, Robert E. Jr., Patt, Frederick S., Barnes, Robert A., and McClain, Charles R. Sat . "SeaWiFS long-term solar diffuser reflectance and sensor noise analyses". United States. doi:10.1364/AO.46.000762.
@article{osti_20929603,
title = {SeaWiFS long-term solar diffuser reflectance and sensor noise analyses},
author = {Eplee, Robert E. Jr. and Patt, Frederick S. and Barnes, Robert A. and McClain, Charles R},
abstractNote = {The NASA Ocean Biology Processing Group's Calibration and Validation(Cal/Val) team has undertaken an analysis of the mission-long Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)solar calibration time series to assess the long-term degradation of the solar diffuser reflectance over 9 years on orbit. The SeaWiFS diffuser is an aluminum plate coated with YB71 paint. The bidirectional reflectance distribution function of the diffuser was not fully characterized before launch,so the Cal/Val team has implemented a regression of the solar incidence angles and the drift in the node of the satellite's orbit against the diffuser time series to correct for solar incidence angle effects. An exponential function with a time constant of 200 days yields the best fit to the diffuser time series.The decrease in diffuser reflectance over the mission is wavelength dependent,ranging from 9% in the blue(412 nm) to 5% in the red and near infrared(670-865 nm). The Cal/Val team has developed a methodology for computing the signal-to-noise ratio (SNR) for SeaWiFS on orbit from the diffuser time series corrected for both the varying solar incidence angles and the diffuser reflectance degradation. A sensor noise model is used to compare on-orbit SNRs computed for radiances reflected from the diffuser with prelaunch SNRs measured at typical radiances specified for the instrument. To within the uncertainties in the measurements, the SNRs for SeaWiFS have not changed over the mission. The on-orbit performance of the SeaWiFS solar diffuser should offer insight into the long-term on-orbit performance of solar diffusers on other instruments, such as the Moderate-Resolution Imaging Spectrometer [currently flying on the Earth Observing System (EOS) Terra and Aqua satellites], the Visible and Infrared Radiometer Suite [scheduled to fly on the NASA National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Project (NPP) satellites] and the Advanced Baseline Imager [scheduled to fly on the National Oceanic and Atmospheric Administration Geostationary Environmental Operational Satellite Series R (GOES-R) satellites].},
doi = {10.1364/AO.46.000762},
journal = {Applied Optics},
number = 5,
volume = 46,
place = {United States},
year = {Sat Feb 10 00:00:00 EST 2007},
month = {Sat Feb 10 00:00:00 EST 2007}
}