Implications of whole-disc DSCOVR EPIC spectral observations for estimating earth's spectral reflectivity based on low-earth-orbiting and geostationary observations

Wanjuan Song, Yuri Knyazikhin, Guoyong Wen, Alexander Marshak, Matti Mõttus, Kai Yan, Bin Yang, Baodong Xu, Taejin Park, Chi Chen, Yelu Zeng, Guangjian Yan, Xihan Mu, Ranga B. Myneni

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Earth's reflectivity is among the key parameters of climate research. National Aeronautics and Space Administration (NASA)'s Earth Polychromatic Imaging Camera (EPIC) onboard National Oceanic and Atmospheric Administration (NOAA)'s Deep Space Climate Observatory (DSCOVR) spacecraft provides spectral reflectance of the entire sunlit Earth in the near backscattering direction every 65 to 110 min. Unlike EPIC, sensors onboard the Earth Orbiting Satellites (EOS) sample reflectance over swaths at a specific local solar time (LST) or over a fixed area. Such intrinsic sampling limits result in an apparent Earth's reflectivity. We generated spectral reflectance over sampling areas using EPIC data. The difference between the EPIC and EOS estimates is an uncertainty in Earth's reflectivity. We developed an Earth Reflector Type Index (ERTI) to discriminate between major Earth atmosphere components: clouds, cloud-free ocean, bare and vegetated land. Temporal variations in Earth's reflectivity are mostly determined by clouds. The sampling area of EOS sensors may not be sufficient to represent cloud variability, resulting in biased estimates. Taking EPIC reflectivity as a reference, low-earth-orbiting-measurements at the sensor-specific LST tend to overestimate EPIC values by 0.8% to 8%. Biases in geostationary orbiting approximations due to a limited sampling area are between -0.7% and 12%. Analyses of ERTI-based Earth component reflectivity indicate that the disagreement between EPIC and EOS estimates depends on the sampling area, observation time and vary between -10% and 23%.
Original languageEnglish
Article number1594
JournalRemote Sensing
Volume10
Issue number10
DOIs
Publication statusPublished - 1 Oct 2018
MoE publication typeNot Eligible

Fingerprint

reflectivity
observatory
climate
sampling
spectral reflectance
sensor
satellite sensor

Keywords

  • Deep Space Climate Observatory (DSCOVR)
  • Earth Polychromatic Imaging Camera (EPIC)
  • GOES-East
  • MISR
  • MODIS
  • Spectral reflectance

Cite this

Song, Wanjuan ; Knyazikhin, Yuri ; Wen, Guoyong ; Marshak, Alexander ; Mõttus, Matti ; Yan, Kai ; Yang, Bin ; Xu, Baodong ; Park, Taejin ; Chen, Chi ; Zeng, Yelu ; Yan, Guangjian ; Mu, Xihan ; Myneni, Ranga B. / Implications of whole-disc DSCOVR EPIC spectral observations for estimating earth's spectral reflectivity based on low-earth-orbiting and geostationary observations. In: Remote Sensing. 2018 ; Vol. 10, No. 10.
@article{e294f23ef3de46d69bb21f06d9b1e52a,
title = "Implications of whole-disc DSCOVR EPIC spectral observations for estimating earth's spectral reflectivity based on low-earth-orbiting and geostationary observations",
abstract = "Earth's reflectivity is among the key parameters of climate research. National Aeronautics and Space Administration (NASA)'s Earth Polychromatic Imaging Camera (EPIC) onboard National Oceanic and Atmospheric Administration (NOAA)'s Deep Space Climate Observatory (DSCOVR) spacecraft provides spectral reflectance of the entire sunlit Earth in the near backscattering direction every 65 to 110 min. Unlike EPIC, sensors onboard the Earth Orbiting Satellites (EOS) sample reflectance over swaths at a specific local solar time (LST) or over a fixed area. Such intrinsic sampling limits result in an apparent Earth's reflectivity. We generated spectral reflectance over sampling areas using EPIC data. The difference between the EPIC and EOS estimates is an uncertainty in Earth's reflectivity. We developed an Earth Reflector Type Index (ERTI) to discriminate between major Earth atmosphere components: clouds, cloud-free ocean, bare and vegetated land. Temporal variations in Earth's reflectivity are mostly determined by clouds. The sampling area of EOS sensors may not be sufficient to represent cloud variability, resulting in biased estimates. Taking EPIC reflectivity as a reference, low-earth-orbiting-measurements at the sensor-specific LST tend to overestimate EPIC values by 0.8{\%} to 8{\%}. Biases in geostationary orbiting approximations due to a limited sampling area are between -0.7{\%} and 12{\%}. Analyses of ERTI-based Earth component reflectivity indicate that the disagreement between EPIC and EOS estimates depends on the sampling area, observation time and vary between -10{\%} and 23{\%}.",
keywords = "Deep Space Climate Observatory (DSCOVR), Earth Polychromatic Imaging Camera (EPIC), GOES-East, MISR, MODIS, Spectral reflectance",
author = "Wanjuan Song and Yuri Knyazikhin and Guoyong Wen and Alexander Marshak and Matti M{\~o}ttus and Kai Yan and Bin Yang and Baodong Xu and Taejin Park and Chi Chen and Yelu Zeng and Guangjian Yan and Xihan Mu and Myneni, {Ranga B.}",
year = "2018",
month = "10",
day = "1",
doi = "10.3390/rs10101594",
language = "English",
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Song, W, Knyazikhin, Y, Wen, G, Marshak, A, Mõttus, M, Yan, K, Yang, B, Xu, B, Park, T, Chen, C, Zeng, Y, Yan, G, Mu, X & Myneni, RB 2018, 'Implications of whole-disc DSCOVR EPIC spectral observations for estimating earth's spectral reflectivity based on low-earth-orbiting and geostationary observations', Remote Sensing, vol. 10, no. 10, 1594. https://doi.org/10.3390/rs10101594

Implications of whole-disc DSCOVR EPIC spectral observations for estimating earth's spectral reflectivity based on low-earth-orbiting and geostationary observations. / Song, Wanjuan; Knyazikhin, Yuri; Wen, Guoyong; Marshak, Alexander; Mõttus, Matti; Yan, Kai; Yang, Bin; Xu, Baodong; Park, Taejin; Chen, Chi; Zeng, Yelu; Yan, Guangjian; Mu, Xihan; Myneni, Ranga B.

In: Remote Sensing, Vol. 10, No. 10, 1594, 01.10.2018.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Implications of whole-disc DSCOVR EPIC spectral observations for estimating earth's spectral reflectivity based on low-earth-orbiting and geostationary observations

AU - Song, Wanjuan

AU - Knyazikhin, Yuri

AU - Wen, Guoyong

AU - Marshak, Alexander

AU - Mõttus, Matti

AU - Yan, Kai

AU - Yang, Bin

AU - Xu, Baodong

AU - Park, Taejin

AU - Chen, Chi

AU - Zeng, Yelu

AU - Yan, Guangjian

AU - Mu, Xihan

AU - Myneni, Ranga B.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - Earth's reflectivity is among the key parameters of climate research. National Aeronautics and Space Administration (NASA)'s Earth Polychromatic Imaging Camera (EPIC) onboard National Oceanic and Atmospheric Administration (NOAA)'s Deep Space Climate Observatory (DSCOVR) spacecraft provides spectral reflectance of the entire sunlit Earth in the near backscattering direction every 65 to 110 min. Unlike EPIC, sensors onboard the Earth Orbiting Satellites (EOS) sample reflectance over swaths at a specific local solar time (LST) or over a fixed area. Such intrinsic sampling limits result in an apparent Earth's reflectivity. We generated spectral reflectance over sampling areas using EPIC data. The difference between the EPIC and EOS estimates is an uncertainty in Earth's reflectivity. We developed an Earth Reflector Type Index (ERTI) to discriminate between major Earth atmosphere components: clouds, cloud-free ocean, bare and vegetated land. Temporal variations in Earth's reflectivity are mostly determined by clouds. The sampling area of EOS sensors may not be sufficient to represent cloud variability, resulting in biased estimates. Taking EPIC reflectivity as a reference, low-earth-orbiting-measurements at the sensor-specific LST tend to overestimate EPIC values by 0.8% to 8%. Biases in geostationary orbiting approximations due to a limited sampling area are between -0.7% and 12%. Analyses of ERTI-based Earth component reflectivity indicate that the disagreement between EPIC and EOS estimates depends on the sampling area, observation time and vary between -10% and 23%.

AB - Earth's reflectivity is among the key parameters of climate research. National Aeronautics and Space Administration (NASA)'s Earth Polychromatic Imaging Camera (EPIC) onboard National Oceanic and Atmospheric Administration (NOAA)'s Deep Space Climate Observatory (DSCOVR) spacecraft provides spectral reflectance of the entire sunlit Earth in the near backscattering direction every 65 to 110 min. Unlike EPIC, sensors onboard the Earth Orbiting Satellites (EOS) sample reflectance over swaths at a specific local solar time (LST) or over a fixed area. Such intrinsic sampling limits result in an apparent Earth's reflectivity. We generated spectral reflectance over sampling areas using EPIC data. The difference between the EPIC and EOS estimates is an uncertainty in Earth's reflectivity. We developed an Earth Reflector Type Index (ERTI) to discriminate between major Earth atmosphere components: clouds, cloud-free ocean, bare and vegetated land. Temporal variations in Earth's reflectivity are mostly determined by clouds. The sampling area of EOS sensors may not be sufficient to represent cloud variability, resulting in biased estimates. Taking EPIC reflectivity as a reference, low-earth-orbiting-measurements at the sensor-specific LST tend to overestimate EPIC values by 0.8% to 8%. Biases in geostationary orbiting approximations due to a limited sampling area are between -0.7% and 12%. Analyses of ERTI-based Earth component reflectivity indicate that the disagreement between EPIC and EOS estimates depends on the sampling area, observation time and vary between -10% and 23%.

KW - Deep Space Climate Observatory (DSCOVR)

KW - Earth Polychromatic Imaging Camera (EPIC)

KW - GOES-East

KW - MISR

KW - MODIS

KW - Spectral reflectance

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U2 - 10.3390/rs10101594

DO - 10.3390/rs10101594

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