Root cause determination of on-orbit degradation of the VIIRS rotating telescope assembly

Barrie, James D.; Fuqua, Peter D.; Meshishnek, M. J.; Ciofalo, Martin R.; Chu, C.-T.; Chaney, John A.; Moision, Robert M.; Graziani, Larissa

doi:10.1117/12.933276

Cited by 36 publications

(32 citation statements)

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“…The S-NPP VIIRS RTA throughput has degraded significantly during the course of on-orbit operations due to unexpected mirror darkening [15]. Because the degradation is wavelength dependent, it has resulted in a significant change to the DNB RSR within its wide band pass.…”

Section: Modulated Rsrmentioning

confidence: 99%

The S-NPP VIIRS Day-Night Band On-Orbit Calibration/Characterization and Current State of SDR Products

et al. 2014

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Abstract:The launch of VIIRS on-board the Suomi-National Polar-orbiting Partnership (S-NPP) on 28 October 2011, marked the beginning of the next chapter on nighttime lights observation started by the Defense Meteorological Satellite Program's (DMSP) OLS sensor more than two decades ago. The VIIRS observes the nighttime lights on Earth through its day-night band (DNB), a panchromatic channel covering the wavelengths from 500 nm to 900 nm. Compared to its predecessors, the VIIRS DNB has a much improved spatial/temporal resolution, radiometric sensitivity and, more importantly, continuous calibration using on-board calibrators (OBCs). In this paper, we describe the current state of the NASA calibration and characterization methodology used in supporting mission data quality assurance and producing consistent mission-wide sensor data records (SDRs) through NASA's Land Product Evaluation and Analysis Tool Element (Land PEATE). The NASA calibration method utilizes the OBCs to determine gains, offset drift and sign-to-noise ratio (SNR) over the entire mission. In gain determination, the time-dependent relative spectral response (RSR) is used to correct the optical throughput change over time. A deep space view acquired during an S-NPP pitch maneuver is used to compute the airglow free dark OPEN ACCESSRemote Sens. 2014, 6 12428 offset for DNB's high gain stage. The DNB stray light is estimated each month from new-moon dark Earth surface observations to remove the excessive stray light over the day-night terminators. As the VIIRS DNB on-orbit calibration is the first of its kind, the evolution of the calibration methodology is evident when the S-NPP VIIRS's official calibrations are compared with our latest mission-wide reprocessing. In the future, the DNB calibration methodology is likely to continue evolving, and the mission-wide reprocessing is a key to providing consistently calibrated DNB SDRs for the user community. In the meantime, the NASA Land PEATE provides an alternative source to obtain mission-wide DNB SDR products that are calibrated based on the latest NASA DNB calibration methodology.

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Section: Modulated Rsrmentioning

confidence: 99%

The S-NPP VIIRS Day-Night Band On-Orbit Calibration/Characterization and Current State of SDR Products

et al. 2014

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“…is mainly due to the degradation of the RTA, which has the largest degradation, around a wavelength of 1000 nm [5,[37][38][39]. Among bands M1-M3, which have the shortest wavelengths, the band with the shorter wavelength has the larger degradation.…”

Section: Hg Ham1mentioning

confidence: 99%

VIIRS Reflective Solar Bands Calibration Progress and Its Impact on Ocean Color Products

Sun

Wang

2016

Remote Sensing

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Abstract:The radiometric calibration for the reflective solar bands (RSB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi National Polar-orbiting Partnership (SNPP) platform has reached a mature stage after four years since its launch. The characterization of the vignetting effect of the attenuation screens, the bidirectional reflectance factor of the solar diffuser, the degradation performance of the solar diffuser, and the calibration coefficient of the RSB have all been made robust. Additional investigations into the time-dependent out-of-band relative spectral response and the solar diffuser degradation non-uniformity effect have led to newer insights. In particular, it has been demonstrated that the solar diffuser (SD) degradation non-uniformity effect induces long-term bias in the SD-calibration result. A mitigation approach, the so-called Hybrid Method, incorporating lunar-based calibration results, successfully restores the calibration to achievẽ 0.2% level accuracy. The successfully calibrated RSB data record significantly impacts the ocean color products, whose stringent requirements are especially sensitive to calibration accuracy, and helps the ocean color products to reach maturity.

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“…These modulated band-averaged RSRs are generated at different times during SNPP mission, and are used to update post-launch SDR Look-Up- Tables (LUT) to correct the RTA mirror contamination effect [15,[18][19][20]. Figure 1 shows DNB and M4-M7 RSRs at orbit 154 (8 November, 2011, same as prelaunch RSRs) and at orbit 20875 (8 November 2015, four years after launch).…”

Section: Relative Spectral Response (Rsr)mentioning

confidence: 99%

“…A double monochromator operating in subtractive mode was used to collect spectral test data in the lab environment for generating VIIRS RSRs [13,14]. Shortly after S-NPP launch, it was observed that several VIIRS reflective bands had decreased optical throughput due to the contamination of the mirror coating on the rotating telescope assembly (RTA) [1,15,16], which also caused the RSRs to change over time. Without updating the RSRs, the sensor radiometric calibration and the computed top-of-the-atmosphere (TOA) spectral reflectance delivered in the Sensor Data Records (SDRs) could be biased [17].…”

Section: Relative Spectral Response (Rsr)mentioning

confidence: 99%

“…L m is provided by the DNB SDRs product directly, which is calibrated considering the response versus scan angle of a rotating half angle mirror and the solar diffuser BRDF degradation using the time-dependent modulated RSR [1,15]. The DNB radiance with the Earth-Sun distance, solar zenith angle, and RSR normalization are calculated using the following Equations (1)-(4).…”

Section: Calculate Radiance and Reflectance Datamentioning

confidence: 99%

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Using Ground Targets to Validate S-NPP VIIRS Day-Night Band Calibration

Chen

Xiong

et al. 2016

Remote Sensing

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Abstract:In this study, the observations from S-NPP VIIRS Day-Night band (DNB) and Moderate resolution bands (M bands) of Libya 4 and Dome C over the first four years of the mission are used to assess the DNB low gain calibration stability. The Sensor Data Records produced by NASA Land Product Evaluation and Algorithm Testing Element (PEATE) are acquired from nearly nadir overpasses for Libya 4 desert and Dome C snow surfaces. A kernel-driven bidirectional reflectance distribution function (BRDF) correction model is used for both Libya 4 and Dome C sites to correct the surface BRDF influence. At both sites, the simulated top-of-atmosphere (TOA) DNB reflectances based on SCIAMACHY spectral data are compared with Land PEATE TOA reflectances based on modulated Relative Spectral Response (RSR). In the Libya 4 site, the results indicate a decrease of 1.03% in Land PEATE TOA reflectance and a decrease of 1.01% in SCIAMACHY derived TOA reflectance over the period from April 2012 to January 2016. In the Dome C site, the decreases are 0.29% and 0.14%, respectively. The consistency between SCIAMACHY and Land PEATE data trends is good. The small difference between SCIAMACHY and Land PEATE derived TOA reflectances could be caused by changes in the surface targets, atmosphere status, and on-orbit calibration. The reflectances and radiances of Land PEATE DNB are also compared with matching M bands and the integral M bands based on M4, M5, and M7. The fitting trends of the DNB to integral M bands ratios indicate a 0.75% decrease at the Libya 4 site and a 1.89% decrease at the Dome C site. Part of the difference is due to an insufficient number of sampled bands available within the DNB wavelength range. The above results indicate that the Land PEATE VIIRS DNB product is accurate and stable. The methods used in this study can be used on other satellite instruments to provide quantitative assessments for calibration stability.

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Root cause determination of on-orbit degradation of the VIIRS rotating telescope assembly

Cited by 36 publications

References 0 publications

The S-NPP VIIRS Day-Night Band On-Orbit Calibration/Characterization and Current State of SDR Products

The S-NPP VIIRS Day-Night Band On-Orbit Calibration/Characterization and Current State of SDR Products

VIIRS Reflective Solar Bands Calibration Progress and Its Impact on Ocean Color Products

Using Ground Targets to Validate S-NPP VIIRS Day-Night Band Calibration

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