Characterization of MODIS solar diffuser on-orbit degradation

Xiong, X.; Xie, Xiaobo; Angal, Amit; Choi, Jong-Soo; Sun, Junqiang; Barnes, William

doi:10.1117/12.731304

Cited by 12 publications

(18 citation statements)

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“…The amount of UV exposure over the mission life is expected to be reasonably stable for each orbit making extrapolation of the early on-orbit results more reliable. The trends of VIIRS F1 are similar to those of Aqua MODIS [3] shown in Figure 3. Unlike Aqua MODIS which has a door to block the UV exposure on the SD when not in calibration mode, the VIIRS SD is exposed to solar illumination every orbit.…”

Section: Resultssupporting

confidence: 79%

NPP VIIRS early on-orbit solar diffuser degradation results

Moyer

Haas

Fulbright

et al. 2012

2012 IEEE International Geoscience and Remote Sensing Symposium

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The Visible-Infrared Imaging Radiometer Suite (VIIRS) was launched October 28, 2011 on-board the Suomi National Polar-orbiting Partnership (NPP) spacecraft as a primary sensor. It has 22 bands: 14 reflective solar bands (RSBs), 7 thermal emissive bands (TEBs) and a Day Night Band (DNB). The RSBs are calibrated using the sun as a source, after attenuation and reflection of sunlight from a Solar Diffuser (SD). To track SD degradation over time, VIIRS incorporates a separate instrument called the Solar Diffuser Stability Monitor (SDSM). The SDSM is a ratio radiometer using views of attenuated direct solar illumination and solar illumination reflected off the SD to track relative change in the SD reflectance over time. This paper will describe the SDSM design and analysis methodology as well as compare the SD degradation trends with its heritage sensor MODIS.

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Section: Resultssupporting

confidence: 79%

NPP VIIRS early on-orbit solar diffuser degradation results

Moyer

Haas

Fulbright

et al. 2012

2012 IEEE International Geoscience and Remote Sensing Symposium

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“…system, large variations existed in its Sun view responses. As a result, an alternative approach was developed by the MODIS Characterization Support Team (MCST) to normalize individual detector responses to those from detector 9 as the SD degradation at this wavelength (0.94 μm) is expected to be extremely small and the patterns in all the detectors are nearly identical 9,12 . In the VIIRS SDSM design, this defect was eliminated.…”

Section: Sd and Sdsm Screenmentioning

confidence: 99%

“…On-orbit SDSM observations have found that the SD degradations for both MODIS and VIIRS have similar wavelengthdependent features with larger degradations occurring at shorter visible (VIS) wavelengths [7][8][9][10][11] . Meanwhile, the SDSM detector responses have also experienced wavelength-dependent degradation, which is larger at longer near-infrared (NIR) wavelengths 12 .…”

Section: Introductionmentioning

confidence: 99%

Improvements of VIIRS and MODIS solar diffuser and lunar calibration

et al. 2013

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Both VIIRS and MODIS instruments use solar diffuser (SD) and lunar observations to calibrate their reflective solar bands (RSB). A solar diffuser stability monitor (SDSM) is used to track the SD on-orbit degradation. On-orbit observations have shown similar wavelength-dependent SD degradation (larger at shorter VIS wavelengths) and SDSM detector response degradation (larger at longer NIR wavelengths) for both VIIRS and MODIS instruments. In general, the MODIS scan mirror has experienced more degradation in the VIS spectral region whereas the VIIRS rotating telescope assembly (RTA) mirrors have seen more degradation in the NIR and SWIR spectral region. Because of this wavelength dependent mirror degradation, the sensor's relative spectral response (RSR) needs to be modulated. Due to differences between the solar and lunar spectral irradiance, the modulated RSR could have different effects on the SD and lunar calibration. In this paper, we identify various factors that should be considered for the improvements of VIIRS and MODIS solar and lunar calibration and examine their potential impact. Specifically, we will characterize and assess the calibration impact due to SD and SDSM attenuation screen transmission (uncertainty), SD BRF uncertainty and onorbit degradation, SDSM detector response degradation, and modulated RSR resulting from the sensor's optics degradation. Also illustrated and discussed in this paper are the calibration strategies implemented in the VIIRS and MODIS SD and lunar calibrations and efforts that could be made for future improvements.

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“…Details of the methodologies and algorithms used to monitor MODIS and VIIRS SD on-orbit degradation can be found in a number of references [10][11][12][13][14] . In this paper, we focus on the SD degradation performance and issues that could impact SD degradation characterization.…”

Section: Sdsm Detector and Sd On-orbit Degradationmentioning

confidence: 99%

“…This approach normalizes SDSM responses to its detector 9 (D9) as SD degradation at this wavelength is extremely small. As mission continues, the D9 degradation is determined separately with a much longer time series and corrected for other detectors in the alternative approach [10][11][12][13] . The VIIRS SDSM system design was improved based on lessons learned from MODIS.…”

Section: Sdsm On-orbit Operationmentioning

confidence: 99%

Assessment of MODIS and VIIRS solar diffuser on-orbit degradation

Xiong

Fulbright

Angal

et al. 2015

Earth Observing Systems XX

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Both MODIS and VIIRS instruments use a solar diffuser (SD) for their reflective solar bands (RSB) on-orbit calibration. On-orbit changes in SD bi-directional reflectance factor (BRF) are tracked by a solar diffuser stability monitor (SDSM) using its alternate measurements of the sunlight reflected off the SD panel and direct sunlight through a fixed attenuation screen. The SDSM calibration data are collected by a number of filtered detectors, covering wavelengths from 0.41 to 0.94 m. In this paper we describe briefly the Terra and Aqua MODIS and S-NPP VIIRS SDSM on-orbit operation and calibration activities and strategies, provide an overall assessment of their SDSM on-orbit performance, including wavelength-dependent changes in the SDSM detector responses and changes in their SD BRF, and discuss remaining challenging issues and their potential impact on RSB calibration quality. Due to different launch dates, operating configurations, and calibration frequencies, the Terra and Aqua MODIS and S-NPP VIIRS SD have experienced different amount of SD degradation. However, in general the shorter the wavelength, the larger is the SD on-orbit degradation. On the other hand, the larger changes in SDSM detector responses are observed at longer wavelengths in the near infrared (NIR).

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Characterization of MODIS solar diffuser on-orbit degradation

Cited by 12 publications

References 0 publications

NPP VIIRS early on-orbit solar diffuser degradation results

NPP VIIRS early on-orbit solar diffuser degradation results

Improvements of VIIRS and MODIS solar diffuser and lunar calibration

Assessment of MODIS and VIIRS solar diffuser on-orbit degradation

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