Estimation of the accuracy of the SNPP VIIRS SD BRDF degradation factor determined by the solar diffuser stability monitor

Lei, Ning; Xiong, Xiaoxiong

doi:10.1117/12.2186636

Cited by 9 publications

(6 citation statements)

References 5 publications

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“…Recently, there have been several studies [34][35][36][37] to improve the modeling accuracy of the VIIRS SD reflectance degradation and the radiometric calibration accuracy of VIIRS RSB sensor. For example, Lei and Xiong presented a method in [34] to determine the SNPP VIIRS SD BRDF degradation factor over wavelengths longer than 1 µm.…”

Section: Discussionmentioning

confidence: 99%

“…In [36,37], Lei and Xiong analyzed the impact of the angular dependence of the VIIRS SD BRDF degradation factor on the radiometric calibration of the RSBs. It was found that the H factors of the SD are angle-dependent.…”

Section: Discussionmentioning

confidence: 99%

“…For the operational calibration of VIIRS RSB, a more comprehensive model that incorporates angular dependence of SD BRDF degradation with more fitting parameters should be used, such as presented in [36,37].…”

Section: Discussionmentioning

confidence: 99%

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Spectral Dependent Degradation of the Solar Diffuser on Suomi-NPP VIIRS Due to Surface Roughness-Induced Rayleigh Scattering

2016

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Abstract:The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar Orbiting Partnership (SNPP) uses a solar diffuser (SD) as its radiometric calibrator for the reflective solar band calibration. The SD is made of Spectralon™ (one type of fluoropolymer) and was chosen because of its controlled reflectance in the Visible/Near-Infrared/Shortwave-Infrared region and its near-Lambertian reflectance property. On-orbit changes in VIIRS SD reflectance as monitored by the Solar Diffuser Stability Monitor showed faster degradation of SD reflectance for 0.4 to 0.6 µm channels than the longer wavelength channels. Analysis of VIIRS SD reflectance data show that the spectral dependent degradation of SD reflectance in short wavelength can be explained with a SD Surface Roughness (length scale << wavelength) based Rayleigh Scattering (SRRS) model due to exposure to solar UV radiation and energetic particles. The characteristic length parameter of the SD surface roughness is derived from the long term reflectance data of the VIIRS SD and it changes at approximately the tens of nanometers level over the operational period of VIIRS. This estimated roughness length scale is consistent with the experimental result from radiation exposure of a fluoropolymer sample and validates the applicability of the Rayleigh scattering-based model. The model is also applicable to explaining the spectral dependent degradation of the SDs on other satellites. This novel approach allows us to better understand the physical processes of the SD degradation, and is complementary to previous mathematics based models.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Spectral Dependent Degradation of the Solar Diffuser on Suomi-NPP VIIRS Due to Surface Roughness-Induced Rayleigh Scattering

2016

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“…The multi-year lunar F relative to its value at a particular time has an accuracy of about 0.1%. We approximate that the accuracy of SDSM H is less than 0.1%, except at the M1 band central wavelength where the accuracy is about 0.001 2 + 0.0005 2 /HRTA 2 [9]. Note that the positional dependence of RTA .…”

Section: Aggregation Impactmentioning

confidence: 81%

SNPP VIIRS RSB earth view reflectance uncertainty

Lei

Twedt

McIntire

et al. 2017

2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

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The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite uses its 14 reflective solar bands to passively collect solar radiant energy reflected off the Earth. The Level 1 product is the geolocated and radiometrically calibrated topof-the-atmosphere solar reflectance. The absolute radiometric uncertainty associated with this product includes contributions from the noise associated with measured detector digital counts and the radiometric calibration bias. Here, we provide a detailed algorithm for calculating the estimated standard deviation of the retrieved top-of-theatmosphere spectral solar radiation reflectance.

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“…The relative transmittance and the relative product are determined from both yaw maneuver and a small portion of regular on-orbit data [11][12] . Unlike the traditional approach 5-8 , the BRDF degradation factors are calculated with the angle between the solar vector and the SD surface centered at 35.5 degrees, avoiding the impact of the angular dependency of the degradation factors 13,14 . In addition, we scale the degradation factors so that their values are equal to one at the initial time, by fitting the factors to a function of the solar radiative energy received by a unit area of the SD surface 13 .…”

Section: Data Selection For Analysismentioning

confidence: 99%

Determination of the SNPP VIIRS solar diffuser BRDF degradation factor over wavelengths longer than 1μm

Lei

Xiong

2015

Earth Observing Systems XX

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To radiometrically calibrate its reflective solar bands, the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (SNPP) satellite observes a sunlit onboard solar diffuser (SD).Once on orbit, the bidirectional reflectance distribution function (BRDF) of the SD degrades over time. The degradation factor is determined by an onboard solar diffuser stability monitor (SDSM). However, the central wavelengths (414 to 929 nm) of the SDSM detectors do not cover the VIIRS short wave infrared (SWIR) bands which have central wavelengths from 1238 to 2257 nm. Although it is known that at wavelengths longer than 1 m the SD BRDF degrades at a much slower rate, the degradation at some of the SWIR bands' central wavelengths may still be non-negligible as Ocean Color products often require a radiometric calibration stability of at least 0.1%. To access the SD BRDF degradation factor in the SWIR bands wavelength region, we investigate a phenomenological model and apply the model to determine the degradation factor in the SWIR bands wavelength region. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 09/29/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite 1 radiometrically calibrates its solar reflective bands (RSBs) by observing a fully solar illuminated solar diffuser (SD) panel 2-4 . The SD bidirectional reflectance distribution function (BRDF) decreases with time. An onboard solar diffuser stability monitor (SDSM) is employed to determine the degradation factor 5-8 .The SDSM observes the Sun through a screen with pinholes (the SDSM screen) and a fully sunlit SD at almost the same time. When used in a time series, the ratio of the observed detector digital counts is a clear measure of the BRDF degradation. However, the eight detectors of the SDSM, spectrally centered from 414 nm to 929 nm 9 , cover much shorter wavelengths than those of the short wave infrared (SWIR) bands in the RSBs. The central wavelengths for the SWIR bands are from 1238 to 2257 nm. In the literature, the SD BRDF degradations over the VIIRS SWIR band wavelengths are ignored 2-4 . To accurately calibrate the SWIR bands and to satisfy the 0.1% radiometric calibration stability requirement for Ocean Color products 10 , we investigate a phenomenological model and apply the model to determine the SD BRDF degradation in the SWIR band wavelength region. DATA SELECTION FOR ANALYSISTo develop a phenomenological model to determine the SD BRDF degradation in the SWIR band wavelength region, we examine the degradation factors (value is one means no degradation) determined by the SDSM observations from detectors 5 to 8 with band central wavelengths of 675 to 929 nm.The degradation factors are calculated with the SDSM screen relative transmittance and the relative product of the SD screen transmittance times the SD BRDF at the initial time when the BRDF started to degrade. T...

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Estimation of the accuracy of the SNPP VIIRS SD BRDF degradation factor determined by the solar diffuser stability monitor

Cited by 9 publications

References 5 publications

Spectral Dependent Degradation of the Solar Diffuser on Suomi-NPP VIIRS Due to Surface Roughness-Induced Rayleigh Scattering

Spectral Dependent Degradation of the Solar Diffuser on Suomi-NPP VIIRS Due to Surface Roughness-Induced Rayleigh Scattering

SNPP VIIRS RSB earth view reflectance uncertainty

Determination of the SNPP VIIRS solar diffuser BRDF degradation factor over wavelengths longer than 1μm

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