Dr. Xi Shao Profile

Dr. Xi Shao

Associate Research Scientist at Univ of Maryland College Park

SPIE Involvement:

Author

Publications (62)

Proceedings Article | 4 October 2023 Presentation + Paper

Preliminary assessment of the NOAA-21 VIIRS on-orbit reflective solar band calibration and performance

Taeyoung Choi, Slawomir Blonski, Xi Shao, Wenhui Wang

Proceedings Volume 12685, 126850Z (2023) https://doi.org/10.1117/12.2677921

KEYWORDS: Calibration, Short wave infrared radiation, Sun, Satellites, Displays, Bidirectional reflectance transmission function, Transmittance, Spectral response, Reflectivity, Equipment

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Proceedings Article | 4 October 2023 Presentation + Paper

Evaluation and correction of NOAA-21 VIIRS day night band stray light and comparison with SNPP and NOAA-20

Xi Shao, Tung-Chang Liu, Slawomir Blonski, Sirish Uprety, Taeyoung Choi

Proceedings Volume 12685, 1268513 (2023) https://doi.org/10.1117/12.2677363

KEYWORDS: Stray light, Satellites, Shadows, Contamination, Space operations, Light sources and illumination, Sunlight, Sensors, Satellite imaging, Auroras

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Proceedings Article | 30 September 2022 Presentation + Paper

Striping analysis and correction for Suomi NPP VIIRS reflective solar bands

Khalil Ahmad, Wenhui Wang, Slawomir Blonski, Xi Shao

Proceedings Volume 12232, 122320N (2022) https://doi.org/10.1117/12.2632366

KEYWORDS: Sensors, Reflectivity, Calibration, Satellites, Satellite imaging, Clouds, Spatial resolution, Meteorological satellites, Image sensors, Target detection, Optical sensors

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Proceedings Article | 30 September 2022 Presentation + Paper

NOAA-20 VIIRS operational radiometric calibration updates for the reflective solar bands

Taeyoung Choi, Slawomir Blonski, Xi Shao, Wenhui Wang, Sirish Uprety, Bin Zhang, Khalil Ahmad, Yan Bai

Proceedings Volume 12232, 122320Q (2022) https://doi.org/10.1117/12.2633518

KEYWORDS: Calibration, Sensors, Reflectivity, Sun, Satellites, Bidirectional reflectance transmission function, Clouds, Transmittance, Satellite imaging, Atmospheric modeling

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SPIE Journal Paper | 21 July 2022 Open Access

Validation of geostationary operational environmental satellite-16 advanced baseline imager radiometric calibration with airborne field campaign data and reanalysis of north-south scan data

Xi Shao, Francis Padula, Changyong Cao, Xiangqian Wu, Fangfang Yu, Aaron Pearlman, Haifeng Qian, Sirish Uprety, Taeyoung Choi

JARS, Vol. 16, Issue 03, 037501, (July 2022) https://doi.org/10.1117/12.10.1117/1.JRS.16.037501

KEYWORDS: Sensors, Calibration, Satellites, Detection and tracking algorithms, Diffusers, Target detection, Sensor performance, Detector arrays, Reflectivity, Algorithm development

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SPIE Journal Paper | 10 December 2021 Open Access

Radiometric calibration accuracy and stability of GOES-16 ABI Infrared radiance

Fangfang Yu, Xiangqian Wu, Hyelim Yoo, Haifeng Qian, Xi Shao, Zhipeng Wang, Robert Iacovazzi

JARS, Vol. 15, Issue 04, 048504, (December 2021) https://doi.org/10.1117/12.10.1117/1.JRS.15.048504

KEYWORDS: Calibration, Satellites, Infrared radiation, Printed circuit board testing, Infrared imaging, Sensors, Scanning probe lithography, Satellite imaging, Samarium, Mid-IR

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Proceedings Article | 1 August 2021 Presentation + Paper

Restoration of degraded Suomi-NPP VIIRS DNB nighttime imagery induced by electronic bias change

Yalong Gu, Slawomir Blonski, Xi Shao, Sirish Uprety, Changyong Cao

Proceedings Volume 11829, 118290V (2021) https://doi.org/10.1117/12.2593739

KEYWORDS: Calibration, Sensors, Image quality, Charge-coupled devices, Satellites, CCD image sensors, Algorithm development

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SPIE Journal Paper | 6 April 2021

Evaluation of aqua MODIS thermal emissive bands stability through radiative transfer modeling

Tung-Chang Liu, Xiaoxiong Xiong, Xi Shao, Yong Chen, Aisheng Wu, Tiejun Chang, Ashish Shrestha

JARS, Vol. 15, Issue 02, 024502, (April 2021) https://doi.org/10.1117/12.10.1117/1.JRS.15.024502

KEYWORDS: MODIS, Carbon monoxide, Atmospheric modeling, Absorption, Calibration, Data modeling, Clouds, Sensors, Ozone, Infrared sensors

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Moderate Resolution Imaging Spectroradiometer (MODIS) on Aqua has been in operation providing continuous global observations for science research and applications since 2002. The long-term stability of thermal emissive bands (TEBs) of Aqua MODIS was monitored through inter-comparisons with measurements by hyperspectral or multi-spectral infrared sensors or through vicarious monitoring over cold targets such as Dome-C and deep convective clouds. The radiative transfer modeling (RTM)-based simulation models are developed to perform the long-term monitoring of the stability of Aqua MODIS TEBs. Long-term European Centre for Medium-Range Weather Forecasts global atmospheric reanalysis data are used as inputs to the RTM simulation. By confining ocean in low to middle latitudes as the area of interest, the long-term stabilities of Aqua MODIS TEBs are monitored through observation minus background (O-B) brightness temperature (BT) bias between MODIS measurements and simulations from the RTM. In general, the RTM-based O-B analysis shows that the long-term stability of Aqua MODIS TEBs are maintained well. It is shown that Aqua MODIS surface bands are all radiometrically stable with yearly BT bias drifts <0.005 K / year for B20, B22, and B23 and ∼0.01 K / year for B31 and B32. The carbon dioxide (CO2) absorption channels of Aqua MODIS, e.g., B33 to B36, are stable with a BT bias drift <0.005 K / year. It is also found that after accounting for the long-term growth of greenhouse gas N2O, the O-B bias trends for B24 and B25 are quite stable with yearly BT bias drifts around 0.0002 and 0.0055 K / year, respectively. The stabilities of the moisture-sensitive channels B27 to B29 and the ozone channel B30 of Aqua MODIS are also evaluated and the remnant small variations in the O-B bias trending of these channels are further discussed. The RTM-based inter-comparison of MODIS TEB measurements with global atmospheric and climate re-analysis data provides validation of the long-term radiometric stability of Aqua MODIS TEBs. The analysis in this paper also demonstrates that the comparison of well-calibrated MODIS TEB measurements with RTM simulation helps quantify the long-term impacts of global greenhouse gas concentration growth on the BT decreases in the MODIS greenhouse gas-sensitive channels.

SPIE Journal Paper | 26 February 2021 Open Access

Characterization and monitoring of GOES-16 ABI stray light and comparison with Himawari-8 AHI and GOES-17 ABI

Xi Shao, Xiangqian Wu, Fangfang Yu, Changyong Cao

JARS, Vol. 15, Issue 01, 017503, (February 2021) https://doi.org/10.1117/12.10.1117/1.JRS.15.017503

KEYWORDS: Stray light, Sun, Contamination, Sensors, Satellites, Infrared imaging, Imaging systems, Satellite imaging, Earth's atmosphere, Stray light analysis

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SPIE Journal Paper | 4 December 2020 Open Access

Validation of GOES-16 ABI VNIR channel radiometric performance with NPP and NOAA-20 VIIRS over the Sonoran Desert

Xin Jing, Tung-Chang Liu, Xi Shao, Sirish Uprety, Bin Zhang, A. Surjalal Sharma

JARS, Vol. 14, Issue 04, 044517, (December 2020) https://doi.org/10.1117/12.10.1117/1.JRS.14.044517

KEYWORDS: Reflectivity, Sensors, Calibration, Bidirectional reflectance transmission function, Earth's atmosphere, Digital filtering, Satellites, Atmospheric corrections, Contamination, Clouds

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The advanced baseline imager (ABI) onboard Geostationary Operational Environmental Satellites-16 (GOES-16) provides high-quality visible and near-infrared (VNIR) imagery data. Radiometric performance of the GOES-16 ABI multiple VNIR bands (B1, B2, B3, B5, and B6) is evaluated over the Sonoran Desert by comparing measurements with Suomi National Polar-Orbiting Partnership (S-NPP) and NOAA-20 visible infrared imaging radiometer suite equivalent bands M3, M5, M7, M10, and M11, respectively. In order to minimize the uncertainties due to the difference in spectral response functions of similar bands from the different sensors, spectral band adjustment factor (SBAF) derived from Hyperion data over Sonoran Desert is used. The large viewing angle at the Sonoran Desert by ABI (56.34 deg) and a lack of comprehensive BRDF model at such viewing geometry are the main challenges for the comparison. Two schemes to address such challenges were developed. A data-derived (DD) method, based on confining the matched solar-zenith angle and view-zenith angle between ABI and VIIRS, interpolation in solar-zenithal and relative-azimuthal angles is developed to address this issue. It is shown that there is some residual bias for ABI B1 and its equivalent VIIRS M3 band, which is mainly due to unaccounted angular dependence of atmospheric scattering in this DD method. To address this issue, a radiative transfer modeling (RTM)-based method to account for atmospheric effects is developed to facilitate the comparison. The time series trending and mean bias of reflectance ratio between ABI and VIIRS measurements over the Sonoran Desert after SBAF and bidirectional reflectance distribution function corrections are derived to evaluate the radiometric performance of ABI with respect to net primary productivity and NOAA-20 VIIRS. The analysis shows that the radiometric biases of the five VNIR channels of GOES-16 ABI are all within 5% in comparison to the matched channels of NPP VIIRS after applying the RTM correction. The analysis also detects ∼6 % drop in the radiometric bias of GOES-16 ABI 0.64 μm channel after April 23, 2019, which can be traced to the implementation of a correction of the ABI B2 calibration coefficient around this date. Further, we evaluate the relative radiometric bias for the five VNIR channels between NPP and NOAA-20 VIIIRS using double difference method, and the comparison shows that NPP VIIRS has 2% to 3% higher bias than NOAA-20 VIIRS for these spectral bands.

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SPIE Journal Paper | 30 September 2020 Open Access

On-orbit calibration and characterization of GOES-17 ABI IR bands under dynamic thermal condition

Zhipeng Wang, Xiangqian Wu, Fangfang Yu, Jon Fulbright, Elizabeth Kline, Hyelim Yoo, Timothy Schmit, Mathew Gunshor, Monica Coakley, Mason Black, Daniel Lindsey, Haifeng Qian, Xi Shao, Robbie Iacovazzi

JARS, Vol. 14, Issue 03, 034527, (September 2020) https://doi.org/10.1117/12.10.1117/1.JRS.14.034527

KEYWORDS: Calibration, Sensors, Printed circuit board testing, Infrared imaging, Infrared sensors, Satellites, Temperature metrology, Infrared detectors, Switches, Long wavelength infrared

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Proceedings Article | 9 September 2020 Presentation + Paper

Radiometric performance characterization of NOAA-20 VIIRS reflective solar bands

Sirish Uprety, Changyong Cao, Xi Shao

Proceedings Volume 11501, 1150115 (2020) https://doi.org/10.1117/12.2568721

KEYWORDS: Reflectivity, Calibration, Sensors, Photonic integrated circuits, Satellites

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NOAA-20 VIIRS Reflective Solar Bands (RSBs) have been performing well since launch with good quality sensor data records (SDRs). The radiometric performance of these SDRs have been continuously analyzed and monitored using various independent validation techniques. It is important to maintain radiometric consistency between NOAA-20 VIIRS SDRs and other well calibrated instruments such as S-NPP VIIRS for long term environmental applications. Past studies have shown that there exists a near consistent bias in RSBs between the two VIIRS instruments, with NOAA-20 VIIRS top-of-atmosphere (TOA) reflectance being lower by nearly 2-3%. It is crucial to monitor the radiometric consistency between the two VIIRS instruments and help the user community understand the trending of the relative bias between two VIIRS and its impacts on the higher level EDR products. This study is focused on analyzing NOAA-20 VIIRS radiometric bias relative to S-NPP VIIRS operational SDR using different techniques such as the pseudo-invariant calibration sites (PICS) and inter-comparison with other satellite instruments using Simultaneous Nadir Overpasses (SNOs). The impact on bias due to spectral differences between the two VIIRS instruments is quantified using hyperspectral measurements from Sciamachy. Since S-NPP VIIRS is used as a reference, any residual degradation in its operational calibration since 2018 needs to be accounted. The correction for residual degradation will be performed in future for more accurate NOAA-20 VIIRS bias trending once the S-NPP VIIRS reprocessing is completed to the more recent date. The study suggests that NOAA-20 VIIRS reflective solar bands are consistently lower in reflectance than that from S-NPP VIIRS by about 2-3% for most bands. Larger bias is observed for bands M5 (0.67 μm) and M7 (0.86 μm) bands mainly because S-NPP VIIRS absolute calibration for these bands is biased high by about 2%. NOAA-20 VIIRS bias values estimated in this study are consistent with the past studies. The bias remains nearly constant for all the bands. Thus, the study also uses the trend-corrected S-NPP VIIRS data to quantify NOAA-20 VIIRS temporal radiometric bias. Due to shorter span of time for NOAA-20 VIIRS, i.e. ~ two years in orbit, analyzing its radiometric stability using calibration sites is more challenging and results in higher uncertainty. This study uses Libya 4 calibration site to further analyze and validate the radiometric.

Proceedings Article | 20 August 2020 Presentation + Paper

Correction of NOAA-20 VIIRS day/night band low-gain stage gain calibration errors by scaling factors derived from prelaunch testing data

Yalong Gu, Slawomir Blonski, Wenhui Wang, Taeyoung Choi, Sirish Uprety, Xi Shao, Changyong Cao

Proceedings Volume 11501, 115010Y (2020) https://doi.org/10.1117/12.2568783

KEYWORDS: Calibration, Sensors, Sun, Satellites, Diffusers, Stray light, Visible radiation, Satellite imaging, Radiometry

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Proceedings Article | 20 August 2020 Presentation + Paper

Update on SNPP and NOAA-20 VIIRS day/night band stray light correction

Xi Shao, Sirish Uprety, Yalong Gu, Slawomir Blonski, Changyong Cao

Proceedings Volume 11501, 1150110 (2020) https://doi.org/10.1117/12.2568055

KEYWORDS: Stray light, Calibration, Sensors, Satellites, Image quality, Detection and tracking algorithms, Space operations, Satellite imaging, Diffusers

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Proceedings Article | 20 August 2020 Poster + Paper

Validation of GOES-16 ABI VNIR channel radiometric performance with NPP VIIRS and AQUA MODIS over the Sonoran Desert

Xin Jing, Tung-Chang Liu, Xi Shao, Sirish Uprety, Bin Zhang, A. Surjalal Sharma

Proceedings Volume 11501, 115011J (2020) https://doi.org/10.1117/12.2568051

KEYWORDS: MODIS, Reflectivity, Sensors, Calibration, Satellites, Atmospheric corrections, Imaging systems

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Proceedings Article | 20 August 2020 Poster + Paper

Long term stability monitoring of Aqua MODIS thermal emissive bands through radiative transfer modeling

Tung-Chang Liu, Xiaoxiong Xiong, Xi Shao, Yong Chen, Aisheng Wu, Tiejun Chang, Ashish Shrestha

Proceedings Volume 11501, 115011K (2020) https://doi.org/10.1117/12.2568052

KEYWORDS: MODIS, Radiative transfer, Absorption, Infrared radiation, Data modeling

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Moderate Resolution Imaging Spectroradiometer (MODIS) on Aqua has been in operation providing continuous global observations for science research and applications since 2002. The long-term stability of thermal emissive bands (TEBs) of Aqua MODIS was monitored through inter-comparisons with measurements by hyperspectral infrared sensors, such as AIRS on Aqua and IASI on MetOp satellite, or through long term vicarious monitoring over cold targets, such as Dome- C and deep convective clouds (DCC). In this paper, a radiative transfer modeling-based simulation model using Community Radiative Transfer Model (CRTM) is developed to perform the long-term monitoring of the stability of TEBs of Aqua MODIS. CRTM is a fast-radiative transfer model for calculations of radiances for satellite infrared radiometers and is able to output infrared radiance and brightness temperature at spectral bands of MODIS. Long term European Centre for Medium-Range Weather Forecasts (ECMWF) global atmospheric reanalysis data, such as temperature and humidity profiles, are used as inputs to the CRTM simulation. By confining the area of interest to be over low to middle latitude ocean, the long-term stabilities of selected Aqua MODIS TEBs are monitored through Observation–Background (O-B) brightness temperature (BT) bias between MODIS measurements and BT retrieval from CRTM simulation. The consistency and relative stability between Aqua MODIS and ECMWF reanalysis data for surface channels of MODIS are evaluated. In addition, the radiative transfer modeling with CRTM enables us to evaluate the impacts of long term variation of global CO₂ distribution on the O-B BT biases for CO₂ channels of Aqua MODIS through comparison of simulations with constant or long term variable CO₂ as inputs. The O-B analysis with RTM show that Aqua MODIS surface channels are all radiometrically stable with yearly BT bias drift less than 0.004K/year for B20, B22, B23 and ~0.01K/year for B31 and B32. The CO2 absorption channels of Aqua MODIS, e.g. B33-B36, are stable with BT bias drift < 0.005K/year.

SPIE Journal Paper | 29 May 2020

Radiometric consistency between GOES-16 ABI and VIIRS on Suomi NPP and NOAA-20

Sirish Uprety, Changyong Cao, Xi Shao

JARS, Vol. 14, Issue 03, 032407, (May 2020) https://doi.org/10.1117/12.10.1117/1.JRS.14.032407

KEYWORDS: Calibration, Reflectivity, Clouds, Satellites, Sensors, Sun, Photonic integrated circuits, Bidirectional reflectance transmission function, Imaging systems, MODIS

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SPIE Journal Paper | 25 February 2020 Open Access

GOES-16 Advanced Baseline Imager instrument performance monitor

Robbie Iacovazzi, Haifeng Qian, Xiangqian Wu, Xi Shao, Fangfang Yu

JARS, Vol. 14, Issue 01, 016512, (February 2020) https://doi.org/10.1117/12.10.1117/1.JRS.14.016512

KEYWORDS: Calibration, Sensors, Imaging systems, Stars, Satellites, Diffusers, Black bodies, Infrared imaging, Data acquisition, Statistical analysis

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Proceedings Article | 9 September 2019 Paper

Physical modeling of NOAA-20 VIIRS solar diffuser stability monitor sun view screen transmittance

Xi Shao, Taeyoung Choi, Changyong Cao, Tung-Chang Liu, Slawomir Blonski, Sirish Uprety, Bin Zhang

Proceedings Volume 11127, 111271R (2019) https://doi.org/10.1117/12.2528460

KEYWORDS: Sun, Transmittance, Calibration, Reflectivity, Satellites, Sensors, Systems modeling, 3D modeling, Diffusers, Computer simulations

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Proceedings Article | 9 September 2019 Paper

Modeling spectral degradation of MODIS and VIIRS solar diffusers

Xi Shao, Tung-Chang Liu, Xiaoxiong Xiong, Changyong Cao, Taeyoung Choi, Amit Angal

Proceedings Volume 11127, 111271S (2019) https://doi.org/10.1117/12.2528442

KEYWORDS: MODIS, Reflectivity, Surface roughness, Calibration, Solar radiation models, Data modeling, Solar radiation, Spectral models, Light scattering, Diffusers

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Proceedings Article | 9 September 2019 Presentation + Paper

Geo-Leo intercalibration to evaluate the radiometric performance of NOAA-20 VIIRS and GOES-16 ABI

Sirish Uprety, Changyong Cao, Xi Shao

Proceedings Volume 11127, 111270S (2019) https://doi.org/10.1117/12.2528468

KEYWORDS: Calibration, Reflectivity, Sensors, Clouds, Satellites, Diffusers, Imaging systems, Factor analysis, Sensor performance

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Proceedings Article | 9 September 2019 Presentation + Paper

NOAA-20 VIIRS initial on-orbit radiometric calibration using scheduled lunar observations

Taeyoung Choi, Xi Shao, Slawomir Blonski, Wenhui Wang, Sirish Uprety, Changyong Cao

Proceedings Volume 11127, 111271Z (2019) https://doi.org/10.1117/12.2528459

KEYWORDS: Calibration, Sensors, Satellites, Sun, Transmittance, Bidirectional reflectance transmission function

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Proceedings Article | 9 September 2019 Presentation + Paper

Radiometric calibration performance of GOES-17 Advanced Baseline Imager (ABI)

Fangfang Yu, Xiangqian Wu, Hyelim Yoo, Zhipeng Wang, Haifeng Qian, Xi Shao

Proceedings Volume 11127, 111271C (2019) https://doi.org/10.1117/12.2531407

KEYWORDS: Calibration, Satellites, Infrared imaging, Terbium, Imaging systems, Satellite imaging, Space operations, Infrared radiation, Visible radiation, Cooling systems

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GOES-17 (G17), the second NOAA’s latest generation weather geostationary GOES-R series satellites, was declared as the operational GOES-West satellite at 137.2° W longitude on February 12, 2019. The Advanced Baseline Imager (ABI) onboard is the primary instrument which is now paired with the GOES-16 (GOES-East) ABI to provide faster, more detailed and accurate measurements for the weather phenomena over the Western Hemisphere compared to the legacy GOES Imagers. Yet right at the beginning of the G17 ABI post-launch test and post-launch product test (PLT/PLPT) in late April 2018, the malfunctioning of Loop Heat Pipe (LHP) on the spacecraft was detected. This anomaly leads to degraded data quality for all the infrared (IR) bands and no useful data for some IR bands during some hours at night of one some days in the year. Despite all the adversities, significant improvements in the L1b radiance have been made. This study reported the radiometric calibration performance for all the G17 ABI bands and the comparison with that of GOES-16 (G16) ABI. During the time when the IR focal plane module (FPM) is controlled, the G17 IR radiometric calibration is generally well calibrated and very stable. The radiometric calibration difference to G16 IR data is within 0.1K for all the IR bands except for B09 at 0.22K and B16 at 0.57K. The predictive calibration algorithm (pCal) which was operationally implemented on July 25, 2019 significantly improves the radiometric calibration accuracy during the time when the IR FPM temperature is unstable. The radiometric calibration accuracy for the visible and near-infrared (VNIR) bands at both G16 and G17 is within 5% using the SNPP/VIIRS as the reference, except for G16 and G17 B02 and G17 B05. With the recent updates of the B02 solar calibration look-up tables, the G16 and G17 B02 radiance are also significantly reduced and comparable to the common reference. Continuous efforts to improve the G17 radiance quality are still ongoing.

Proceedings Article | 9 September 2019 Paper

Modeling transmittance of MODIS solar diffuser stability monitor sun view screen

Tung-Chang Liu, Xiaoxiong Xiong, Xi Shao

Proceedings Volume 11127, 1112727 (2019) https://doi.org/10.1117/12.2528207

KEYWORDS: Sun, Transmittance, MODIS, Calibration, Sensors, Computer simulations, Mirrors, Diffusers, Space operations, Reflectivity

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Proceedings Article | 9 September 2019 Presentation + Paper

Correction of detector nonlinearity induced striping in VIIRS day/night band nighttime imagery

Yalong Gu, Sirish Uprety, Xi Shao, Slawomir Blonski, Wenhui Wang, Changyong Cao

Proceedings Volume 11127, 111271T (2019) https://doi.org/10.1117/12.2528025

KEYWORDS: Sensors, Calibration, Satellite imaging, Visible radiation, Nonlinear response

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Proceedings Article | 19 November 2018 Paper

NOAA-20 VIIRS on-orbit performance, data quality, and operational Cal/Val support

Changyong Cao, Slawomir Blonski, Wenhui Wang, Sirish Uprety, Xi Shao, Jason Choi, Erin Lynch, Satya Kalluri

Proceedings Volume 10781, 107810K (2018) https://doi.org/10.1117/12.2324329

KEYWORDS: Calibration, Signal to noise ratio, Infrared radiation, Long wavelength infrared, Diffusers, Infrared imaging, Reflectivity, Sensors, Satellites, MODIS

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Proceedings Article | 23 October 2018 Paper

Evaluating NOAA-20 and S-NPP VIIRS radiometric consistency

Sirish Uprety, Changyong Cao, Slawomir Blonski, Xi Shao

Proceedings Volume 10781, 107810V (2018) https://doi.org/10.1117/12.2324464

KEYWORDS: MODIS, Calibration, Diffusers, Bidirectional reflectance transmission function, Satellites, Radiometry

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Proceedings Article | 23 October 2018 Paper

Characterization and correction of stray light for NOAA-20 VIIRS day/night band

Xi Shao, Changyong Cao, Tung-Chang Liu, Sirish Uprety, Bin Zhang, Wenhui Wang, Slawomir Blonski

Proceedings Volume 10781, 107810H (2018) https://doi.org/10.1117/12.2323981

KEYWORDS: Stray light, Sensors, Space operations, Satellites, Diffusers, Contamination, Charge-coupled devices, CCD image sensors, Auroras, Calibration

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Proceedings Article | 25 September 2018 Paper

Improving NOAA 20 VIIRS screen transmittance and solar diffuser BRF estimation from both Yaw maneuver and regular on-orbit data

Taeyoung Choi, Slawomir Blonski, Xi Shao, Changyong Cao

Proceedings Volume 10785, 1078516 (2018) https://doi.org/10.1117/12.2324335

KEYWORDS: Sensors, Sun, Transmittance, Calibration, Diffusers, Reflectivity, Bidirectional reflectance transmission function, Satellite imaging, Satellites, Radiometry

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Proceedings Article | 7 September 2018 Paper

A light contamination ranking index-based method for automating VIIRS day/night band stray light correction

Xi Shao, Tung-Chang Liu, Sirish Uprety, Wenhui Wang, Bin Zhang, Changyong Cao

Proceedings Volume 10764, 107641I (2018) https://doi.org/10.1117/12.2322999

KEYWORDS: Stray light, Contamination, Sensors, Auroras, Diffusers, Light, Image processing, Calibration, Satellites

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Proceedings Article | 7 September 2018 Paper

Radiometric quality assessment of GOES-16 ABI L1b images

Zhipeng Wang, Xiangqian Wu, Haifeng Qian, Fangfang Yu, Robert Iacovazzi, Xi Shao, Vladimir Kondratovich, Hyelim Yoo

Proceedings Volume 10764, 107641T (2018) https://doi.org/10.1117/12.2322896

KEYWORDS: Sensors, Calibration, Signal to noise ratio, Clouds, Infrared imaging, Satellites, Image quality, Interference (communication), Image processing, Fourier transforms

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Proceedings Article | 7 September 2018 Presentation + Paper

In-orbit response versus scan-angle (RVS) validation for the GOES-16 ABI solar reflective bands

Fangfang Yu, Xi Shao, Xiangqian Wu, Haifeng Qian

Proceedings Volume 10764, 107640E (2018) https://doi.org/10.1117/12.2322154

KEYWORDS: Sensors, Calibration, Mirrors, Reflectivity, Imaging systems, Satellites, Solids, Data modeling, Satellite imaging, Meteorological satellites

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Proceedings Article | 7 September 2018 Presentation + Paper

Validation of GOES-16 ABI infrared spatial response uniformity

Fangfang Yu, Xiangqian Wu, Haifeng Qian, John Van Naarden, Michael Ramirez, Dan Lindsey, Chad Gravelle, Mathew Gunshor, Tim Schmit, Xi Shao, Zhipeng Wang, Hyelim Yoo, Bob Iacovazzi, Vladimir Kondratovich

Proceedings Volume 10764, 107640F (2018) https://doi.org/10.1117/12.2322147

KEYWORDS: Calibration, Mirrors, Infrared imaging, Terbium, Satellites, Space mirrors, Infrared radiation, Printed circuit board testing, Aerospace engineering, Imaging systems

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Proceedings Article | 7 September 2018 Paper

Detection and characterization of striping in GOES-16 ABI VNIR/IR bands

Haifeng Qian, Xiangqian Wu, Fangfang Yu, Xi Shao, Robert Iacovazzi, Zhipeng Wang, Hyelim Yoo

Proceedings Volume 10764, 107641N (2018) https://doi.org/10.1117/12.2321100

KEYWORDS: Calibration, Sensors, Infrared imaging, Mercury cadmium telluride, Satellites, Statistical analysis, Image quality, Imaging systems, Satellite imaging, Image segmentation

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Proceedings Article | 7 September 2018 Paper

Validation of GOES-16 ABI reflective solar band calibration through reanalysis and comparison with field campaign data

Xi Shao, Xiangqian Wu, Changyong Cao, Sirish Uprety, Fangfang Yu, Haifeng Qian, Frank Padula, Aaron Pearlman, Taeyoung Choi, Brent Bartlett, Jason Casey

Proceedings Volume 10764, 107640I (2018) https://doi.org/10.1117/12.2323024

KEYWORDS: Sensors, Calibration, Reflectivity, Detection and tracking algorithms, Data conversion, Diffusers, Detector arrays, Data modeling, Spatial resolution, Mirrors

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Proceedings Article | 7 September 2018 Paper

NOAA-20 VIIRS radiometric band saturation evaluation and comparison with Suomi NPP VIIRS using global probability distribution function method

Bin Zhang, Changyong Cao, Sirish Uprety, Xi Shao

Proceedings Volume 10764, 107641Q (2018) https://doi.org/10.1117/12.2321971

KEYWORDS: Sensors, Stray light, Clouds, Calibration, Satellites, Aerosols

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NOAA-20 was successfully launched on Nov. 18, 2017. Intensive radiometric calibration and validation activities for VIIRS onboard NOAA-20 were carried out immediately after the sensor data become available. Several bands of NOAA-20 VIIRS such as M6, and M8 have maximum dynamic range requirements or waivers on the saturation value and require post-launch assessment of the impacts on the L1B (or EDR) products. Since the saturation threshold in data processing is defined as the measured Digital Number (DN) count, the corresponding saturation radiance value in the L1B data product can vary due to detector difference and degradation in the sensor optical throughput. On the other hand, users of L1B data care more about the accuracy of scene-dependent radiance value and the impact of detector saturation on the radiance data. In order to validate the detector saturation level and assess their impacts on the radiance data products, histogram-based Probability Distribution Function (PDF) is derived both at detector level and at band level from the daily global radiance data. With such distribution function, the saturation level in radiance can be identified from the sharp fold-over and cut-off at the high radiance value in the distribution. In addition, the percentage of the affected pixels in the global data can be quantified and the detector performance can be compared. Since NOAA- 20 and SNPP are 50 minutes apart in the same orbital plane and have the same equator-crossing time, the probability distribution function method also enables comparison of the radiometric calibration performance between the two sensors. For example, the saturation radiance value for VIIRS M6 on NOAA-20 is ~44.2 (W/m²-sr-um) on 01/11/2018, which is ~26% lower than that of SNPP VIIRS. Such difference can be traced to the more rapid degradation of rotating telescope assembly mirror reflectance in SNPP VIIRS. In addition to saturation analysis, the PDF method allows us to analyze the VIIRS Day/Night Band (DNB) according to the solar zenith angle range, and the performance of stray light correction can be compared between SNPP and NOAA-20 as well.

Proceedings Article | 7 September 2018 Paper

Orbital variations and impacts on observations from SNPP, NOAA 18-20, and AQUA sun-synchronous satellites

Xi Shao, Changyong Cao, Xiaoxiong Xiong, Tung-chang Liu, Bin Zhang, Sirish Uprety

Proceedings Volume 10764, 107641U (2018) https://doi.org/10.1117/12.2323012

KEYWORDS: Satellites, MODIS, Temperature metrology, Visible radiation, Infrared imaging, Radiometry, Environmental monitoring, Earth observing sensors, Sensors, Weather forecasting

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Proceedings Article | 5 September 2017 Presentation + Paper

Validation of early GOES-16 ABI on-orbit geometrical calibration accuracy using SNO method

Fangfang Yu, Xi Shao, Xiangqian Wu, Vladimir Kondratovich, Zhengping Li

Proceedings Volume 10402, 104020U (2017) https://doi.org/10.1117/12.2275196

KEYWORDS: Calibration, Image registration, Satellite imaging, Meteorological satellites, Satellites, Reflectivity, Weather forecasting, Natural disasters

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Proceedings Article | 5 September 2017 Presentation + Paper

Early radiometric calibration performances of GOES-16 advanced baseline imager

Fangfang Yu, Xiangqian Wu, Xi Shao, Boryana Efremova, Hyelim Yoo, Haifeng Qian, Bob Iacovazzi

Proceedings Volume 10402, 104020S (2017) https://doi.org/10.1117/12.2275195

KEYWORDS: Calibration, Satellites, Imaging systems, Meteorological satellites, Weather forecasting, Environmental sensing, Climatology, Diffusers, Black bodies, Visible radiation

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Proceedings Article | 19 September 2016 Presentation + Paper

Initial design and performance of the near surface unmanned aircraft system sensor suite in support of the GOES-R field campaign

Aaron Pearlman, Francis Padula, Xi Shao, Changyong Cao, Steven Goodman

Proceedings Volume 9972, 99720U (2016) https://doi.org/10.1117/12.2238178

KEYWORDS: Sensors, Satellites, Calibration, Spectrometers, Polarization, Reflectivity, Temperature metrology, Short wave infrared radiation, Radiative transfer, Lamps

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Proceedings Article | 19 September 2016 Presentation + Paper

Characterization of Himawari-8 AHI 3.9-um channel stray light

Xi Shao, Xiangqian Wu, Fangfang Yu

Proceedings Volume 9972, 99720R (2016) https://doi.org/10.1117/12.2237052

KEYWORDS: Stray light, Imaging systems, Satellites, Calibration, Sun, Image processing, Mid-IR, Sensors, Solar radiation, Clouds

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SPIE Journal Paper | 11 March 2016

Feasibility demonstration for calibrating Suomi-National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite day/night band using Dome C and Greenland under moon light

Shi Qiu, Xi Shao, Changyong Cao, Sirish Uprety

JARS, Vol. 10, Issue 01, 016024, (March 2016) https://doi.org/10.1117/12.10.1117/1.JRS.10.016024

KEYWORDS: Calibration, Reflectivity, Atmospheric modeling, Sensors, Bidirectional reflectance transmission function, Radiometry, Infrared imaging, Performance modeling, Visible radiation, Satellites

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Proceedings Article | 12 October 2015 Paper

Auroral activities observed by SNPP VIIRS day/night band during a long period geomagnetic storm event on April 29-30, 2014

Xi Shao, Changyong Cao, Tung-chang Liu, Bin Zhang, Wenhui Wang, Shing Fung

Proceedings Volume 9639, 963921 (2015) https://doi.org/10.1117/12.2193911

KEYWORDS: Auroras, Magnetism, Stray light, Solar processes, Sensors, Satellites, Electrons, Radiometry, Contamination, CCD image sensors

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The Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi-NPP represents a major advancement in night time imaging capabilities. The DNB senses radiance that can span 7 orders of magnitude in one panchromatic (0.5-0.9 μm) reflective solar band and provides imagery of clouds and other Earth features over illumination levels ranging from full sunlight to quarter moon. When the satellite passes through the day-night terminator, the DNB sensor is affected by stray light due to solar illumination on the instrument. With the implementation of stray light correction, stray light-corrected DNB images enable the observation of aurora occurred in the high latitude regions during geomagnetic storms. In this paper, DNB observations of auroral activities are analyzed during a long period (> 20 hours) of geomagnetic storm event occurred on Apr. 29-30, 2014. The storm event has the Bz component of interplanetary magnetic field (IMF) pointing southward for more than 20 hours. During this event, the geomagnetic storm index Dst reached -67 nT and the geomagnetic auroral electrojet (AE) index increased and reached as high as 1200 nT with large amplitude fluctuations. The event occurred during new moon period and DNB observation has minimum moon light contamination. During this event, auroras are observed by DNB for each orbital pass on the night side (~local time 1:30am) in the southern hemisphere. DNB radiance data are processed to identify regions of aurora during each orbital pass. The evolution of aurora is characterized with time series of the poleward and equatorward boundary of aurora, area, peak radiance and total light emission of the aurora in DNB observation. These characteristic parameters are correlated with solar wind and geomagnetic index parameters. It is found that the evolution of total area-integrated radiance of auroral region over the southern hemisphere correlated well with the ground geomagnetic AE index with correlation coefficient = 0.71. DNB observations of aurora help understand the relations among solar wind variation, auroral activities and geomagnetic responses.

Proceedings Article | 12 October 2015 Paper

Selenographic coordinate mapping of lunar observations by GOES imager

Xi Shao, Xiangqian Wu, Fangfang Yu

Proceedings Volume 9639, 963918 (2015) https://doi.org/10.1117/12.2193914

KEYWORDS: Imaging systems, Calibration, Satellites, Algorithm development, Image processing, Satellite imaging, Image segmentation, Reflectivity, Earth observing sensors, Performance modeling

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Proceedings Article | 8 September 2015 Paper

Assessment of scan-angle dependent radiometric bias of Suomi-NPP VIIRS day/night band from night light point source observations

Yan Bai, Changyong Cao, Xi Shao

Proceedings Volume 9607, 960727 (2015) https://doi.org/10.1117/12.2187119

KEYWORDS: Bridges, Calibration, Light, Light sources, Diffusers, Satellites, Spatial resolution, Light emitting diodes, Point spread functions, Data corrections

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Proceedings Article | 8 September 2015 Paper

Vicarious validation of straylight correction for VIIRS day/night band using Dome-C

Shi Qiu, Xi Shao, Changyong Cao, Wenhui Wang

Proceedings Volume 9607, 96072H (2015) https://doi.org/10.1117/12.2188401

KEYWORDS: Sensors, Calibration, Satellites, Domes, Staring arrays, Neodymium, Infrared imaging, Radiometry, Air contamination, Clouds

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Proceedings Article | 8 September 2015 Paper

Preliminary study for improving the VIIRS DNB low light calibration accuracy with ground based active light source

Changyong Cao, Yuqing Zong, Yan Bai, Xi Shao

Proceedings Volume 9607, 96070D (2015) https://doi.org/10.1117/12.2187580

KEYWORDS: Calibration, Light sources, Bridges, Light, Clouds, Aerosols, Earth's atmosphere, Infrared imaging, Light emitting diodes, Reflection

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Proceedings Article | 26 November 2014 Paper

Feasibility study of remote sensing using structured light for 3D damage assessments after natural disasters

Shi Qiu, Changyong Cao, Bin Zhang, Xi Shao, Wang Xie, Yan Bai, Chuanrong Li

Proceedings Volume 9263, 92632R (2014) https://doi.org/10.1117/12.2068760

KEYWORDS: 3D metrology, Remote sensing, Natural disasters, Cameras, Phase shifts, Reconstruction algorithms, Satellites, Detector arrays, 3D displays, Structured light

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Proceedings Article | 26 November 2014 Paper

Xi Shao, Taeyoung Choi, Changyong Cao, Slawomir Blonski, Wenhui Wang, Yan Ban

Proceedings Volume 9264, 92640K (2014) https://doi.org/10.1117/12.2068474

KEYWORDS: Calibration, Radiometry, Satellites, Diffusers, Sensors, Reflectivity, Short wave infrared radiation, Satellite imaging, Visible radiation, MODIS

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Radiometric stability of the lunar surface and its smooth reflectance spectrum makes the moon an ideal target for calibrating satellite-based hyper/multi-band visible imagers, as demonstrated in several lunar calibration studies of satellite radiometers. Most of the lunar calibrations rely on using lunar irradiance models to calibrate satellite radiometers, which require the lunar irradiance model to be highly accurate. In this paper, we use Lunar Band Ratio (LBR) to trend satellite radiometer performance so that the usage of lunar irradiance model is not required. The LBR method is applied to monitor long term radiometric performance of VIIRS (Visible Infrared Imaging Radiometer Suite) onboard Suomi-NPP. VIIRS observes moon at nearly the same lunar phase angle through Earth view during scheduled spacecraft maneuver. Total lunar digital number are calculated for each VIIRS reflective solar bands (RSBs) from lunar observations and one of the most stable bands of VIIRS such as M4 band is chosen as the reference band for calculating the band ratio. LBRs are compared with the degradation factors derived from VIIRS operational radiometric calibration of RSBs using onboard solar diffuser. The LBR analysis reveals that M6 and M7 degrade the fastest and agree well with the trending independently determined from onboard solar diffuser. For stable bands such as M3-M4 of VIIRS, the variation range of band ratios of M2/M4 and M3/M4 are all within 0.6%, indicating the LBR can be used to reveal the sub percent band to band stability. For M11 band of VIIRS, there have been large uncertainties in verifying its radiometric performance using vicarious ground targets. LBR of M11 provides an independent and useful radiometric stability monitoring tool for verifying the relative stability of M11 band. The LBR analysis also shows that band-to-band variability in the spectrally similar band pairs such as I2 vs. M7 and I3 vs. M10 of VIIRS are consistent within 0.2%. It is demonstrated that long-term performance monitoring of VIIRS instrument using LBR is an important part of the VIIRS lunar calibration for solar bands and can effectively reveal the degradation of instruments.

Proceedings Article | 19 November 2014 Paper

Modeling phase-angle dependence of lunar irradiance using long-term lunar measurements by VIRS on TRMM

Xi Shao, Bin Zhang, Changyong Cao

Proceedings Volume 9264, 92641E (2014) https://doi.org/10.1117/12.2068467

KEYWORDS: Reflectivity, Data modeling, Calibration, Satellites, Radiometry, Sensors, Space operations, Visible radiation, Infrared radiation, Sun

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Proceedings Article | 19 November 2014 Paper

Overview of Suomi NPP VIIRS performance in the last 2.5 years

Changyong Cao, Slawomir Blonski, Wenhui Wang, Xi Shao, Tayoung Choi, Yan Bai, Xiaoxiong Xiong

Proceedings Volume 9264, 926402 (2014) https://doi.org/10.1117/12.2068991

KEYWORDS: Calibration, Diffusers, Mirrors, Reflectivity, Telescopes, Solar energy, Sensors, MODIS, Black bodies, Stars

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Proceedings Article | 19 November 2014 Paper

Radiometric calibration of DMSP-OLS sensor using VIIRS day/night band

Xi Shao, Changyong Cao, Bin Zhang, Shi Qiu, Christopher Elvidge, Michael Von Hendy

Proceedings Volume 9264, 92640A (2014) https://doi.org/10.1117/12.2068999

KEYWORDS: Calibration, Sensors, Satellites, Sensor calibration, Domes, Data conversion, Imaging systems, Spatial resolution, Reflectivity, Data modeling

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Proceedings Article | 19 November 2014 Paper

Suomi NPP VIIRS calibration knowledge base for SDR data quality assurance, anomaly investigation, and EDR applications

Yan Bai, Changyong Cao, Xi Shao, Wenhui Wang

Proceedings Volume 9264, 92641M (2014) https://doi.org/10.1117/12.2069006

KEYWORDS: Calibration, Databases, Bridges, Space operations, Clouds, Image processing, Visible radiation, Infrared imaging, Radiometry, Neodymium

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Proceedings Article | 8 November 2014 Paper

Analysis of satellite-based aerosol optical thickness over China in 2013

F. Meng, C. Y. Cao, X. Shao

Proceedings Volume 9259, 92590W (2014) https://doi.org/10.1117/12.2068439

KEYWORDS: Aerosols, Phase modulation, Satellites, Atmospheric particles, Ocean optics, Clouds, Radiometry, In situ metrology, Remote sensing, Radio optics

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Proceedings Article | 2 October 2014 Paper

Developing an automated global validation site time series system for VIIRS

Wenhui Wang, Changyong Cao, Sirish Uprety, Yan Bai, Frank Padula, Xi Shao

Proceedings Volume 9218, 921823 (2014) https://doi.org/10.1117/12.2060430

KEYWORDS: Calibration, Reflectivity, Clouds, Sensors, Databases, Satellites, Data archive systems, Atmospheric monitoring, Visible radiation, Infrared imaging

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Proceedings Article | 26 September 2014 Paper

Comparing Hyperion Lunar Observation with Model Calculations in Support of GOES-R Advanced Baseline Imager (ABI) Calibration

Xi Shao, Changyong Cao, Sirish Uprety, Frank Padula, Taeyoung Choi

Proceedings Volume 9218, 92181X (2014) https://doi.org/10.1117/12.2062250

KEYWORDS: Reflectivity, Calibration, Satellites, Short wave infrared radiation, Performance modeling, Solar radiation models, Imaging systems, Visible radiation, Infrared radiation, Infrared imaging

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Proceedings Article | 23 May 2014 Paper

VIIRS reflective solar bands calibration changes and potential impacts on ocean color applications

Slawomir Blonski, Changyong Cao, Xi Shao, Sirish Uprety

Proceedings Volume 9111, 911106 (2014) https://doi.org/10.1117/12.2053315

KEYWORDS: Calibration, Diffusers, Reflectivity, Sensors, Telescopes, Space operations, Space telescopes, Mirrors, Radiometry, Contamination

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Proceedings Article | 23 May 2014 Paper

A fast target detection and imaging method for compressive sensing Earth observation

Chuanrong Li, Qi Wang, Changyong Cao, Xi Shao, Lingling Ma, Yongsheng Zhou, Shi Qiu, Jianjian Li

Proceedings Volume 9109, 91090T (2014) https://doi.org/10.1117/12.2050253

KEYWORDS: Digital micromirror devices, Target detection, Image resolution, Mirrors, Compressed sensing, Sensors, Detection and tracking algorithms, Cameras, Reconstruction algorithms, Image processing

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Proceedings Article | 23 September 2013 Paper

Vicarious calibration of S-NPP/VIIRS day-night band

Xi Shao, Changyong Cao, Sirish Uprety

Proceedings Volume 8866, 88661S (2013) https://doi.org/10.1117/12.2023412

KEYWORDS: Reflectivity, Calibration, Sensors, Satellites, Diffusers, Spectral models, Magnesium, Domes, Bidirectional reflectance transmission function, Atmospheric modeling

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Proceedings Article | 23 September 2013 Paper

Evaluating radiometric consistency between Suomi NPP VIIRS and NOAA-19 AVHRR using extended simultaneous nadir overpass in the low latitudes

Sirish Uprety, Changyong Cao, Slawomir Blonski, Xi Shao

Proceedings Volume 8866, 88660L (2013) https://doi.org/10.1117/12.2023335

KEYWORDS: Calibration, Satellites, MODIS, Reflectivity, Radiometry, Sensors, Absorption, Domes, Spatial resolution, Climatology

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Proceedings Article | 9 November 2012 Paper

Calibration of low gain radiance at VIIRS emissive band (M13) and VIIRS image about moon temperature

Quanhua Liu, Kwofu Chiang, Changyong Cao, Jack Xiong, Xi Shao, Slawek Blonski, Fuzhong Weng

Proceedings Volume 8528, 85280O (2012) https://doi.org/10.1117/12.979701

KEYWORDS: Calibration, Temperature metrology, Sensors, Black bodies, Reflectivity, MODIS, Flame detectors, Infrared radiation, Spatial resolution, Environmental sensing

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Proceedings Article | 15 October 2012 Paper

Design and development of carbon nanotube and graphene based microbolometer for IR imaging applications

Ashok Sood, E. Egerton, Yash Puri, Neil Goldsman, Xi Shao, Akin Akturk, Nibir Dhar, Madan Dubey, Priyalal Wijewarnasuriya, Bobby Lineberry

Proceedings Volume 8512, 851205 (2012) https://doi.org/10.1117/12.974241

KEYWORDS: Bolometers, Graphene, Resistance, Microbolometers, Infrared radiation, Carbon nanotubes, Infrared bolometers, Infrared imaging, Sensors, Mid-IR

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