Dr. Taeyoung J. Choi Profile

Dr. Taeyoung J. Choi

Sr. Scientist at NOAA NESDIS

SPIE Involvement:

Author

Publications (52)

Proceedings Article | 10 January 2025 Paper

Long-term on-orbit performance of the VIIRS on Suomi NPP, NOAA-20, and NOAA-21 in reference to partner missions

Changyong Cao, Slawomir Blonski, Xi Shao, Wenhui Wang, Taeyoung Choi, Feng Zhang, Sirish Uprety, Yan Bai

Proceedings Volume 13267, 1326708 (2025) https://doi.org/10.1117/12.3042122

KEYWORDS: Calibration, Radiometry, Satellites, Diffusers, Satellite imaging, Reflection, Equipment, Visible radiation, Tunable filters, Time series analysis

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Since its successful launch in 2011, the VIIRS (Visible Infrared Imaging Radiometer Suite) on Suomi NPP (Suomi National Polar-orbiting Partnership) has been providing continuous global Earth observations with 22 spectral bands spanning 0.41 to 12.01 μm for over a decade. Originally designed for a 7-year lifespan, Suomi NPP VIIRS has consistently exceeded both its operational specifications and user expectations, successively served as the primary, secondary, and now tertiary satellite imaging radiometer for the NOAA’s Joint Polar Satellite System (JPSS) program. Meanwhile, VIIRS on NOAA-20 (launched 2017) and NOAA-21 (launched 2022) have become the secondary and primary imaging radiometers in succession. Building upon lessons learned from SNPP, NOAA-20 VIIRS has distinguished itself as having the most stable reflective solar bands with less than 0.15% responsivity degradation per year in the first 5 years before any correction, and has been endorsed by the World Meteorological Organization/Global Space-based Calibration System (WMO/GSICS) as the on-orbit stability reference. More recently, NOAA-21 VIIRS has become the primary instrument, demonstrating robust performance, especially after the second mid-mission outgassing. This paper evaluates the on-orbit performance of VIIRS instruments, incorporating comprehensive assessments with the calibration methodologies encompassing onboard, vicarious, intercalibration, and recalibration techniques. It focuses on the long-term stability, accuracy, and intersatellite bias assessments using various methods. The root cause for the radiometric biases for the reflective solar bands between Suomi NPP and NOAA-20/-21 is explored, and the recalibration methodology to improve stability and consistency is discussed. Collaborative initiatives with partner satellite programs such as MODIS, the recently launched PACE, EMIT, and the to-be-launched METImage on EPS-SG have also been initiated. These activities underscore the efforts towards achieving consistent, long-term global Earth observations, which are crucial for facilitating time series analyses that support studies on atmosphere, land, ocean dynamics, and artificial nightlight, thereby enhancing global climate change research and operational support for numerical weather predictions.

Proceedings Article | 10 January 2025 Poster + Paper

Long short-term memory (LSTM) deep learning-based prediction of sensor performance time series for improved VIIRS reflective solar band calibration

Tung-Chang Liu, Xi Shao, Taeyoung Choi, Feng Zhang

Proceedings Volume 13267, 132670V (2025) https://doi.org/10.1117/12.3045240

KEYWORDS: Calibration, Reflection, Diffusers, Sensor performance, Deep learning, Charged particle optics, Short wave infrared radiation, Radio optics, Neural networks, Machine learning

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Past experience from postlaunch calibrations of Suomi-NPP (SNPP), NOAA-20, and NOAA-21 Visible Infrared Imaging Radiometer Suite (VIIRS) indicates the critical need for quick and accurate predictions of sensor optical throughput response changes. For example, the solar diffuser is a critical component of the VIIRS instrument and serves as a reference standard for the on-orbit calibration of VIIRS reflective solar bands (RSBs). However, the solar diffuser can experience degradation over time resulting from various factors, including exposure to solar ultraviolet (UV) radiation, energetic particles, and contaminants in the space environment. The changes in the optical properties of the solar diffuser material can impact the accuracy and stability of VIIRS radiometric calibration. SNPP VIIRS RSB suffered rapid postlaunch optical throughput degradation in the near-infrared (NIR) band gains (inverse of solar-F factor calibration coefficient) due to mirror contamination along the optical path. Given the short-term and long-term VIIRS radiometric calibration update needs and the delays between planning and execution of post-launch calibration updates, it is critical to accurately predict VIIRS sensor response changes in days or weeks ahead. The advancement of recurrent neural network (RNN) machine learning algorithm for time series prediction provides potential means for fast and accurate calibration time series prediction. In this study, long short-term memory (LSTM) RNN model is used to train and predict VIIRS calibration time series such as VIIRS solar diffuser spectral reflectance change time series. LSTM neural networks are a type of RNN architecture designed to model sequential data and capture short- and long-term dependencies and are well-suited for calibration time series forecasting due to their ability to remember information over extended time periods and to handle sequences of varying lengths. The calibration time series of solar diffuser reflectance change from SNPP VIIRS are used as example input sequences and target values to train the LSTM model. The prediction performance is assessed in terms of prediction error as a function of prediction horizons from one to seven days for spectral bands of VIIRS. The relative Root Mean Square Error (RMSE) of seven-day LSTM predictions of spectral degradations of SNPP solar diffuser reflectance is within 0.2%. The suitability of applying LSTM machine learning model for VIIRS calibration time series predictions is discussed.

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 | 4 October 2023 Presentation + Paper

Evaluation of NOAA-21 VIIRS thermal emissive bands early on-orbit calibration performance

Wenhui Wang, Slawomir Blonski, Taeyoung Choi

Proceedings Volume 12685, 1268511 (2023) https://doi.org/10.1117/12.2676084

KEYWORDS: Calibration, Long wavelength infrared, Mid-IR, Equipment, Space operations, Emissivity, Short wave infrared radiation, Satellites, Gain switching, Bias correction

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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 | 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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Proceedings Article | 1 August 2021 Presentation + Paper

The effects of NOAA-20 VIIRS Solar Diffuser Stability Monitor (SDSM) Relative Spectral Response (RSR) on the Solar Diffuser (SD) degradation estimations

Taeyoung Choi

Proceedings Volume 11829, 118290W (2021) https://doi.org/10.1117/12.2593935

KEYWORDS: Sensors, Calibration, Diffusers, Surface roughness, Sun, Satellites, Detection and tracking algorithms, Reflectivity, MODIS, Bidirectional reflectance transmission function

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Proceedings Article | 1 August 2021 Presentation + Paper

NOAA 20 VIIRS Solar Diffuser Stability Monitor (SDSM) sun transmittance function update from Yaw maneuver and 3 year on-orbit SDSM data

Taeyoung Choi

Proceedings Volume 11829, 118290X (2021) https://doi.org/10.1117/12.2593940

KEYWORDS: Sun, Sensors, Transmittance, Calibration, Diffusers, Reflectivity, Satellites, Bidirectional reflectance transmission function, Ultraviolet radiation, Spatial resolution

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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 | 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 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 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 | 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 | 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 Presentation + Paper

Initial on-orbit radiometric calibration of the NOAA-20 VIIRS Reflective Solar Bands

Taeyoung Choi, Slawomir Blonski, Changyong Cao

Proceedings Volume 10764, 107641B (2018) https://doi.org/10.1117/12.2321752

KEYWORDS: Calibration, Sensors, Sun, Reflectivity, Transmittance, Satellites, Diffusers, Infrared imaging, Infrared radiation, Radiometry

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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 | 5 September 2017 Presentation + Paper

Suomi-NPP VIIRS initial reprocessing improvements and validations in the reflective solar bands (RSBs)

Taeyoung Choi, Junqiang Sun, Bin Zhang, Zhuo Wang, Changyong Cao, Fuzhong Weng, Menghua Wang

Proceedings Volume 10402, 104021V (2017) https://doi.org/10.1117/12.2274081

KEYWORDS: Calibration, Reflectivity, Visible radiation, Infrared imaging, Radiometry, Sensors, Infrared sensors, Remote sensing, Data processing, Satellites

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SPIE Journal Paper | 15 March 2017

On-orbit evaporative fraction estimations using a histogram-based triangle method from Terra MODIS

Taeyoung Choi, John Qu

JARS, Vol. 11, Issue 01, 016038, (March 2017) https://doi.org/10.1117/12.10.1117/1.JRS.11.016038

KEYWORDS: Francium, MODIS, Algorithm development, Vegetation, Soil science, Sensors, Reflectivity, Error analysis, Environmental sensing, Atmospheric sensing

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Proceedings Article | 19 September 2016 Presentation + Paper

S-NPP VIIRS thermal emissive band gain correction during the blackbody warm-up-cool-down cycle

Taeyoung Choi, Changyong Cao, Fuzhong Weng

Proceedings Volume 9972, 99721J (2016) https://doi.org/10.1117/12.2236995

KEYWORDS: Calibration, Black bodies, Visible radiation, Infrared imaging, Sensors, Temperature metrology, Satellites, MODIS, Critical dimension metrology, Reflectivity

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Proceedings Article | 8 September 2015 Paper

Analysis of VIIRS TEB noise using solar diffuser measurements

Taeyoung Choi, Changyong Cao, Fuzhong Weng

Proceedings Volume 9607, 960723 (2015) https://doi.org/10.1117/12.2188386

KEYWORDS: Sensors, Calibration, Diffusers, Signal to noise ratio, Black bodies, Solids, Interference (communication), Radiometry, Visible radiation, Infrared imaging

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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.

SPIE Journal Paper | 20 November 2014

On-orbit performance of MODIS solar diffuser stability monitor

Xiaoxiong Xiong, Amit Angal, Junqiang Sun, Taeyoung Choi, Eric Johnson

JARS, Vol. 8, Issue 01, 083514, (November 2014) https://doi.org/10.1117/12.10.1117/1.JRS.8.083514

KEYWORDS: MODIS, Calibration, Sensors, Sun, Diffusers, Reflectivity, Near infrared, Signal to noise ratio, Space operations, Radiometry

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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 | 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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SPIE Journal Paper | 6 June 2014

Assessment of the spectral stability of Libya 4, Libya 1, and Mauritania 2 sites using Earth Observing One Hyperion

Taeyoung Choi, Xiaoxiong Xiong, Amit Angal, Gyanesh Chander, John Qu

JARS, Vol. 8, Issue 01, 083618, (June 2014) https://doi.org/10.1117/12.10.1117/1.JRS.8.083618

KEYWORDS: Reflectivity, Photonic integrated circuits, Calibration, Sensors, Satellites, Visualization, Satellite communications, Earth observing sensors, Clouds, Advanced distributed simulations

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Proceedings Article | 16 October 2013 Paper

Status of MODIS on-orbit calibration and characterization

X. Xiong, B. Wenny, J. Sun, A. Angal, A. Wu, H. Chen, X. Geng, T. Choi, S. Madhavan, D. Link, W. Barnes, Vincent Salomonson

Proceedings Volume 8889, 88890U (2013) https://doi.org/10.1117/12.2028953

KEYWORDS: MODIS, Calibration, Sensors, Staring arrays, Long wavelength infrared, Mirrors, Space operations, Sensor calibration, Near infrared, Neodymium

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Proceedings Article | 23 September 2013 Paper

On-orbit calibration performance of MODIS TDI bands

Mike Chu, Junqiang Sun, Amit Angal, Hongda Chen, Xu Geng, Taeyoung Choi, Xiaoxiang (Jack) Xiong

Proceedings Volume 8866, 886605 (2013) https://doi.org/10.1117/12.2024864

KEYWORDS: Calibration, MODIS, Sensors, Signal detection, Mirrors, Satellites, Environmental monitoring, Diffusers, Reflectivity, Imaging systems

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Proceedings Article | 3 June 2013 Paper

Terra and Aqua MODIS on-orbit spectral characterization for reflective solar bands

Taeyoung (Jason) Choi, Xiaoxiong (Jack) Xiong, Zhipeng Wang, Daniel Link

Proceedings Volume 8724, 87240Y (2013) https://doi.org/10.1117/12.2016640

KEYWORDS: MODIS, Calibration, Short wave infrared radiation, Lamps, Spectral calibration, Sensors, Reflectivity, Diffraction gratings, Diffraction

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Proceedings Article | 3 June 2013 Paper

Spectral stability of the Libya 4 site using EO-1 Hyperion

Taeyoung (Jason) Choi, Xiaoxiong (Jack) Xiong, Amit Angal, Gyanesh Chander

Proceedings Volume 8724, 872410 (2013) https://doi.org/10.1117/12.2016644

KEYWORDS: Reflectivity, Calibration, Sensors, Satellites, Absorption, Landsat, Aerosols, Photonic integrated circuits, Earth observing sensors, Earth's atmosphere

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To assess the on-orbit radiometric stability of imaging sensors, pseudo-invariant calibration sites (PICS) have been utilized and recommended by the Committee on Earth Observation Satellites (CEOS). In the African continent, the Libya 4 test site has been frequently used to detect long-term changes because of its spatial uniformity, temporal stability, and low atmospheric aerosol loading. The nominal location of the Libya 4 test site is centered at the latitude and longitude of +28.55° and +23.99° with a suggested usable area of 75 x 75 km. Previous cross-calibration studies have used subset areas of the test site around the CEOS suggested center coordinate regardless of the spectral characteristic of the site. In this study, yearly hyper-spectral collections from 2004 to 2012 around day of the year 170 were used from Earth Observing One (EO-1) Hyperion sensor over the Libya 4 site. To evaluate the spectral stability over a broad range over the Libya 4 site, a series of Region of Interest (ROI) covering approximate areas of 3 by 3 km were selected in the along track direction from +28.07° to 29.55° of latitude (about 170 km long), which is also a subset of the CEOS reference site. The reflectance variations in other ROIs are initially estimated by average deviation and compared with the spectral angle mapper (SAM) method using ROI number ‘0’ in year 2004 collection as a reference spectrum. To consider a practical application, SAM and average deviation metrics are limited by the wavelength ranges of Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) Relative Spectral Response (RSR), instead of using the entire range of the Hyperion spectrum. These ETM+ RSR’s focused SAM values are considered to be the sensor specific spectral stability of the Libya 4 site. The Libya 4 CEOS test site is shown to be a spectrally stable target where SAM angles are less than 1.6 degrees and average deviations are less than 5% reflectance level based on the reference spectrum in 2004 within ETM+ RSR Full- Width at Half-Maximum (FWHM) ranges.

Proceedings Article | 28 November 2012 Paper

An overview of MODIS RSB calibration and look-up-table delivery process

A. Angal, H. Chen, T. Choi, X. Geng, J. Sun, B. Wenny, X. Xiong

Proceedings Volume 8528, 85280L (2012) https://doi.org/10.1117/12.977550

KEYWORDS: MODIS, Calibration, Sensors, Mirrors, Reflectivity, Neodymium, Diffusers, Signal to noise ratio, Space operations, Ions

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Proceedings Article | 28 November 2012 Paper

MODIS reflective solar bands calibration improvements in Collection 6

Junqiang Sun, Amit Angal, Xiaoxiong Xiong, Hongda Chen, Xu Geng, Aisheng Wu, Taeyoung Choi, Mike Chu

Proceedings Volume 8528, 85280N (2012) https://doi.org/10.1117/12.979733

KEYWORDS: MODIS, Sensors, Calibration, Mirrors, Reflectivity, Algorithm development, Diffusers, Detection and tracking algorithms, Short wave infrared radiation, Near infrared

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Proceedings Article | 19 November 2012 Paper

Overview of Aqua MODIS 10-year on-orbit calibration and performance

X. Xiong, B. Wenny, J. Sun, A. Angal, A. Wu, H. Chen, T. Choi, S. Madhavan, X. Geng, D. Link, Z. Wang, G. Toller, W. Barnes, V. Salomonson

Proceedings Volume 8533, 853316 (2012) https://doi.org/10.1117/12.973769

KEYWORDS: Calibration, MODIS, Sensors, Long wavelength infrared, Staring arrays, Near infrared, Sensor calibration, Reflectivity, Diffusers, Spectral calibration

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Proceedings Article | 9 November 2012 Paper

Using CEOS reference standard targets to assess on-orbit performance of Resourcesat-2 AWiFS in comparison with Terra MODIS-preliminary results

A. Angal, A. Senthil Kumar, X. Xiong, A. S. Kiran Kumar, V. Dadhwal, T. Choi

Proceedings Volume 8528, 85280K (2012) https://doi.org/10.1117/12.977549

KEYWORDS: MODIS, Sensors, Reflectivity, Calibration, Molybdenum, Spatial resolution, Image resolution, Neodymium, Satellites, Visible radiation

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Proceedings Article | 15 October 2012 Paper

On-orbit Performance of MODIS Solar Diffuser Stability Monitor

Xiaoxiong (Jack) Xiong, Amit Angal, Taeyoung Choi, Junqiang Sun, Eric Johnson

Proceedings Volume 8510, 85100H (2012) https://doi.org/10.1117/12.930963

KEYWORDS: MODIS, Sensors, Calibration, Sun, Diffusers, Near infrared, Signal attenuation, Reflectivity, Radiometry, Satellites

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Proceedings Article | 14 September 2011 Paper

On-orbit modulation transfer function characterization of terra MODIS using the moon

Zhipeng Wang, Taeyoung Choi, Xiaoxiong Xiong

Proceedings Volume 8153, 81531N (2011) https://doi.org/10.1117/12.892118

KEYWORDS: Modulation transfer functions, MODIS, Calibration, Sensors, Spatial resolution, Fourier transforms, Staring arrays, Image fusion, Remote sensing, Sensing systems

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Proceedings Article | 14 September 2011 Paper

Results of MODIS band-to-band registration characterization using on-orbit lunar observations

Xiaoxiong Xiong, Junqiang Sun, Amit Angal, Yong Xie, Taeyoung Choi, Zhipeng Wang

Proceedings Volume 8153, 81531R (2011) https://doi.org/10.1117/12.893224

KEYWORDS: MODIS, Sensors, Calibration, Near infrared, Long wavelength infrared, Image registration, Radio optics, Spectral calibration, Image resolution, Mercury cadmium telluride

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Proceedings Article | 14 September 2011 Paper

Characterization of MODIS mirror side difference in the reflective solar spectral region

X. Geng, A. Angal, J. Sun, A. Wu, T. Choi, X. Xiong

Proceedings Volume 8153, 81531O (2011) https://doi.org/10.1117/12.892488

KEYWORDS: Mirrors, MODIS, Polarization, Calibration, Reflectivity, Sensors, Space operations, Visible radiation, Sun, Aerospace engineering

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SPIE Journal Paper | 1 January 2011 Open Access

Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors

Amit Angal, Gyanesh Chander, Xiaoxiong Xiong, Taeyoung Choi, Aisheng Wu

JARS, Vol. 5, Issue 1, 059502, (January 2011) https://doi.org/10.1117/12.10.1117/1.3613963

KEYWORDS: Reflectivity, Calibration, Sensors, Earth observing sensors, Bidirectional reflectance transmission function, MODIS, Satellites, Landsat, Spatial resolution, Climatology

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Proceedings Article | 11 November 2010 Paper

Monitoring the long term stability of the IRS-P6 AWiFS sensor using the Sonoran and RVPN sites

Gyanesh Chander, Aparajithan Sampath, Amit Angal, Taeyoung Choi, Xiaoxiong Xiong

Proceedings Volume 7862, 78620K (2010) https://doi.org/10.1117/12.869537

KEYWORDS: Sensors, Reflectivity, Image processing, Calibration, Landsat, Multispectral imaging, Spatial resolution, Remote sensing, Statistical analysis, Earth observing sensors

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Proceedings Article | 4 November 2010 Paper

Simulation of the long term radiometric responses of the Terra MODIS and EO-1 ALI using Hyperion spectral responses over Railroad Valley Playa in Nevada (RVPN)

Taeyoung Choi, Xiaoxiong Xiong, Amit Angal, Gyanesh Chander

Proceedings Volume 7862, 78620H (2010) https://doi.org/10.1117/12.868963

KEYWORDS: Alternate lighting of surfaces, MODIS, Reflectivity, Sensors, Absorption, Spatial resolution, Spectral resolution, Space operations, Calibration, Imaging systems

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Proceedings Article | 4 November 2010 Paper

Results and lessons from a decade of Terra MODIS on-orbit spectral characterization

Xiaoxiong Xiong, Taeyoung Choi, Nianzeng Che, Zhipeng Wang, Jennifer Dodd, Yong Xie, William Barnes

Proceedings Volume 7862, 78620M (2010) https://doi.org/10.1117/12.868930

KEYWORDS: MODIS, Calibration, Sensors, Spectral calibration, Near infrared, Lamps, Mirrors, Long wavelength infrared, Sensor performance

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Proceedings Article | 14 October 2010 Paper

Aqua MODIS 8-year on-orbit operation and calibration

Xiaoxiong Xiong, Amit Angal, Sriharsha Madhavan, Taeyoung Choi, Jennifer Dodd, Xu Geng, Zhipeng Wang, Gary Toller, William Barnes

Proceedings Volume 7826, 78261X (2010) https://doi.org/10.1117/12.864172

KEYWORDS: MODIS, Calibration, Sensors, Staring arrays, Near infrared, Long wavelength infrared, Mirrors, Mid-IR, Photovoltaics, Short wave infrared radiation

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Proceedings Article | 14 October 2010 Paper

Preliminary assessment of several parameters to measure and compare usefulness of the CEOS reference pseudo-invariant calibration sites

Gyanesh Chander, Amit Angal, Xiaoxiong Xiong, Dennis Helder, Nischal Mishra, Taeyoung Choi, Aisheng Wu

Proceedings Volume 7826, 78262L (2010) https://doi.org/10.1117/12.865166

KEYWORDS: Calibration, Sensors, Photonic integrated circuits, Reflectivity, Satellites, Vegetation, Infrared sensors, Infrared radiation, Aerosols, Earth observing sensors

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Proceedings Article | 28 August 2010 Paper

MODIS calibration algorithm improvements developed for Collection 6 Level-1B

Brian Wenny, Junqiang Sun, Xiaoxiong Xiong, Aisheng Wu, Hongda Chen, Amit Angal, Taeyoung Choi, Na Chen, Sriharsha Madhavan, Xu Geng, James Kuyper, Liqin Tan

Proceedings Volume 7807, 78071F (2010) https://doi.org/10.1117/12.860892

KEYWORDS: MODIS, Sensors, Calibration, Algorithm development, Mirrors, Detection and tracking algorithms, Space operations, Temperature metrology, Data processing, Reflectivity

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SPIE Journal Paper | 1 April 2010

Using the Sonoran and Libyan Desert test sites to monitor the temporal stability of reflective solar bands for Landsat 7 enhanced thematic mapper plus and Terra moderate resolution imaging spectroradiometer sensors

Amit Angal, Xiaoxiong Xiong, Taeyoung Choi, Gyanesh Chander, Aisheng Wu

JARS, Vol. 4, Issue 01, 043525, (April 2010) https://doi.org/10.1117/12.10.1117/1.3424910

KEYWORDS: MODIS, Reflectivity, Sensors, Calibration, Bidirectional reflectance transmission function, Remote sensing, Landsat, Image sensors, Spatial resolution, Earth observing sensors

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Proceedings Article | 23 September 2009 Paper

Cross-comparison of the IRS-P6 AWiFS sensor with the L5 TM, L7 ETM+, & Terra MODIS sensors

Gyanesh Chander, Xiaoxiong Xiong, Amit Angal, Taeyoung Choi, Rimy Malla

Proceedings Volume 7474, 74740Z (2009) https://doi.org/10.1117/12.830502

KEYWORDS: Sensors, MODIS, Reflectivity, Landsat, Image sensors, Calibration, Satellites, Spatial resolution, Image analysis, Earth observing sensors

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Proceedings Article | 12 August 2009 Paper

Using the Sonoran Desert test site to monitor the long-term radiometric stability of the Landsat TM/ETM+ and Terra MODIS sensors

A. Angal, X. Xiong, T. Choi, G. Chander, A. Wu

Proceedings Volume 7456, 745606 (2009) https://doi.org/10.1117/12.825075

KEYWORDS: MODIS, Reflectivity, Sensors, Calibration, Bidirectional reflectance transmission function, Landsat, Spatial resolution, Satellites, Clouds, Earth observing sensors

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Proceedings Article | 20 August 2008 Paper

MODIS along-scan direction Line Spread Function (LSF) modeling and verification using the Integration and Alignment Collimator (IAC)

N. Che, T. Choi, X. Xiong, D. Moyer

Proceedings Volume 7081, 708109 (2008) https://doi.org/10.1117/12.793388

KEYWORDS: Sensors, Modulation transfer functions, MODIS, Fourier transforms, Convolution, Collimators, Zemax, Point spread functions, Integrated optics, Calibration

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Proceedings Article | 20 August 2008 Paper

Radiometric cross-calibration of the Terra MODIS and Landsat 7 ETM+ using an invariant desert site

Taeyoung Choi, Amit Angal, Gyanesh Chander, Xiaoxiong Xiong

Proceedings Volume 7081, 708110 (2008) https://doi.org/10.1117/12.793829

KEYWORDS: MODIS, Sensors, Reflectivity, Calibration, Landsat, Spatial resolution, Image sensors, Sensor calibration, Image processing, Earth observing sensors

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Proceedings Article | 20 August 2008 Paper

On-orbit aqua MODIS modulation transfer function trending in along-scan from the Spectro-Radiometric Calibration Assembly

Taeyoung Choi, Nianzeng Che, Xiaoxiong Xiong

Proceedings Volume 7081, 70810A (2008) https://doi.org/10.1117/12.793844

KEYWORDS: Modulation transfer functions, MODIS, Near infrared, Sensors, Staring arrays, Calibration, Signal to noise ratio, Collimators, Mirrors, Point spread functions

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Proceedings Article | 5 October 2007 Paper

Cross-calibration of the Terra MODIS, Landsat 7 ETM+ and EO-1 ALI sensors using near-simultaneous surface observation over the Railroad Valley Playa, Nevada, test site

Gyanesh Chander, Amit Angal, Taeyoung Jason Choi, David Meyer, Xiaoxiong Jack Xiong, Philippe Teillet

Proceedings Volume 6677, 66770Y (2007) https://doi.org/10.1117/12.734292

KEYWORDS: MODIS, Sensors, Alternate lighting of surfaces, Reflectivity, Calibration, Landsat, Image sensors, Spatial resolution, Imaging systems, Earth observing sensors

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Showing 5 of 52 publications

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