Sciences and Exploration Directorate

Amit Angal

(SENIOR ENGINEER)

 amit.a.angal@nasa.gov

Org Code: 618

NASA/GSFC
Mail Code: 618
Greenbelt, MD 20771

Employer: SCIENCE SYSTEMS AND APPLICATIONS INC

Current Projects


MODIS Characterization Support Team

  • On-orbit operation and characterization of the MODIS instruments onboard the Terra and Aqua satellites


VIIRS Characterization Support Team

  • Support the pre-flight characterization of the JPSS-2, 3, and 4 VIIRS instruments
  • On-orbit calibration of the Suomi NPP and NOAA-20 VIIRS instruments

Professional Societies


IEEE

2021 - Present


SPIE

Conference Program Committee – SPIE Optical Engineering + Applications (2020-2022)

2016 - Present

Awards


2022 NASA Robert H. Goddard-Exceptional Achievement for Customer Service to JPSS-2 Instrument Development and Delivery Team

2019 Terra Missions' Pecora Team Award in recognition of significant contributions as a part of the MODIS Characterization Support Team

2018 NOAA & NASA Group Achievement Award to the JPSS-1 Project Team for outstanding contributions to the successful launch and activation of the JPSS-1 Satellite

2017 Hydrosphere, Biosphere and Geophysics HBG Annual Peer Award for Scientific/Technical Support

2016 NASA Group Achievement Award (MODIS Characterization Support Team)

2012 HOBI Group Achievement Award (MODIS Characterization Support Team and MODIS sensor Working Group)

2005 USGS EROS Group Achievement Award for the successful implementation of an image assessment system for EO-1 ALI

Selected Publications


Refereed

McIntire, J., D. Moyer, A. Angal, and X. Xiong. 2023. JPSS-3 / 4 VIIRS response versus scan angle characterization and performance Frontiers in Remote Sensing 4 [10.3389/frsen.2023.1303347]

Wu, A., X. Xiong, A. Angal, Q. Mu, and S. Li. 2023. Assessment of the Radiometric Calibration Consistency of Reflective Solar Bands between Terra and Aqua MODIS in Upcoming Collection-7 L1B Remote Sensing 15 (19): 4730 [10.3390/rs15194730]

Lyapustin, A., M. Choi, Y. Wang, et al. X. Xiong, A. Angal, A. Wu, D. R. Doelling, R. Bhatt, S. Go, S. V. Korkin, B. A. Franz, G. Meister, A. M. Sayer, M. O. Román, R. E. Holz, K. G. Meyer, J. F. Gleason, and R. C. Levy. 2023. Calibration of the SNPP and NOAA 20 VIIRS sensors for continuity of the MODIS climate data records Remote Sensing of Environment 295 113717 [10.1016/j.rse.2023.113717]

Moyer, D., A. Angal, Q. Ji, J. McIntire, and X. Xiong. 2022. JPSS-2 VIIRS Pre-Launch Reflective Solar Band Testing and Performance Remote Sensing 14 (24): 6353 [10.3390/rs14246353]

Moyer, D., A. Angal, H. Oudrari, et al. E. Haas, Q. Ji, F. De Luccia, and X. Xiong. 2022. JPSS-1 VIIRS Prelaunch Reflective Solar Band Testing and Performance Remote Sensing 14 (20): 5113 [10.3390/rs14205113]

Xiong, X., J. Sun, A. Angal, and T. Wilson. 2022. Calibration Inter-Comparison of MODIS and VIIRS Reflective Solar Bands Using Lunar Observations Remote Sensing 14 (19): 4754 [10.3390/rs14194754]

Wu, A., X. Xiong, R. Bhatt, et al. C. Haney, D. R. Doelling, A. Angal, and Q. Mu. 2022. An Assessment of SNPP and NOAA20 VIIRS RSB Calibration Performance in NASA SIPS Reprocessed Collection-2 L1B Data Products Remote Sensing 14 (17): 4134 [10.3390/rs14174134]

Angal, A., X. Xiong, T. Chang, et al. K. Twedt, X. Geng, A. Wu, and E. Aldoretta. 2022. Terra and Aqua MODIS collection 7 level 1B algorithm Journal of Applied Remote Sensing 16 (03): [10.1117/1.jrs.16.037502]

Mu, Q., X. Xiong, K. Twedt, A. Angal, and X. Geng. 2022. Characterization of the on-orbit response versus scan angle for Terra MODIS SWIR bands in Collection 7 Journal of Applied Remote Sensing 16 (02): [10.1117/1.jrs.16.024520]

McIntire, J., X. Xiong, J. J. Butler, et al. A. Angal, D. Moyer, Q. Ji, T. Schwarting, D. Link, and C. Sun. 2022. An Overall Assessment of JPSS-3 VIIRS Radiometric Performance Based on Pre-Launch Testing Remote Sensing 14 (9): 1999 [10.3390/rs14091999]

Angal, A., C. Bruegge, X. Xiong, and A. Wu. 2022. Intercalibration of the reflective solar bands of MODIS and MISR instruments on the Terra platform Journal of Applied Remote Sensing 16 (02): [10.1117/1.jrs.16.027501]

Twedt, K., N. Lei, X. Xiong, et al. A. Angal, S. Li, T. Chang, and J. Sun. 2022. On-Orbit Calibration and Performance of NOAA-20 VIIRS Reflective Solar Bands IEEE Transactions on Geoscience and Remote Sensing 60 1-13 [10.1109/tgrs.2021.3108970]

Twedt, K. A., S. Henderson, X. Xiong, A. Angal, and X. Geng. 2022. Nonlinear Detector Response of Aqua MODIS Land Imaging Bands IEEE Transactions on Geoscience and Remote Sensing 60 1-10 [10.1109/tgrs.2021.3075384]

Angal, A., X. Xiong, and T. Wilson. 2022. Unscheduled Lunar Observations for Radiometric Characterization of VIIRS Reflective Solar Bands IEEE Transactions on Geoscience and Remote Sensing 60 1-8 [10.1109/tgrs.2021.3112820]

Sun, J., X. Xiong, N. Lei, et al. S. Li, K. Twedt, and A. Angal. 2021. Ten Years of SNPP VIIRS Reflective Solar Bands On-Orbit Calibration and Performance Remote Sensing 13 (15): 2944 [10.3390/rs13152944]

Angal, A., X. Xiong, K. Thome, and B. N. Wenny. 2021. Cross-Calibration of Terra and Aqua MODIS Using RadCalNet IEEE Geoscience and Remote Sensing Letters 18 (2): 188-192 [10.1109/lgrs.2020.2973535]

Xiong, X., A. Angal, Y. Li, and K. Twedt. 2020. Improvements of on-orbit characterization of Terra MODIS short-wave infrared spectral bands out-of-band responses Journal of Applied Remote Sensing 14 (04): [10.1117/1.jrs.14.047503]

Lei, N., K. A. Twedt, X. Xiong, and A. Angal. 2020. Performance of NOAA-20 VIIRS Solar Diffuser and Solar Diffuser Stability Monitor IEEE Transactions on Geoscience and Remote Sensing 59 (9): 7180-7188 [10.1109/tgrs.2020.3032068]

Xiong, X., A. Angal, T. Chang, et al. K. Chiang, N. Lei, Y. Li, J. Sun, K. Twedt, and A. Wu. 2020. MODIS and VIIRS Calibration and Characterization in Support of Producing Long-Term High-Quality Data Products Remote Sensing 12 (19): 3167 [10.3390/rs12193167]

Xiong, X., E. Aldoretta, A. Angal, et al. T. Chang, X. Geng, D. Link, V. Salomonson, K. Twedt, and A. Wu. 2020. Terra MODIS: 20 years of on-orbit calibration and performance Journal of Applied Remote Sensing 14 (03): 1 [10.1117/1.jrs.14.037501]

Angal, A., X. Geng, X. Xiong, et al. K. A. Twedt, A. Wu, D. O. Link, and E. Aldoretta. 2020. On-Orbit Calibration of Terra MODIS VIS Bands Using Polarization-Corrected Desert Observations IEEE Transactions on Geoscience and Remote Sensing 58 (8): 5428-5439 [10.1109/tgrs.2020.2966000]

Angal, A., X. Xiong, and A. Shrestha. 2020. Cross-Calibration of MODIS Reflective Solar Bands With Sentinel 2A/2B MSI Instruments IEEE Transactions on Geoscience and Remote Sensing 58 (7): 5000-5007 [10.1109/tgrs.2020.2971462]

Twedt, K. A., A. Angal, and X. Xiong. 2020. Effects of out-of-band and time-varying relative spectral response on the calibration of MODIS reflective solar bands Journal of Applied Remote Sensing 14 (02): 1 [10.1117/1.jrs.14.024523]

Yu, S., R. Rosenberg, C. Bruegge, et al. L. Chapsky, D. Fu, R. Lee, T. Taylor, H. Cronk, C. O’Dell, A. Angal, X. Xiong, D. Crisp, and A. Eldering. 2020. Stability Assessment of OCO-2 Radiometric Calibration Using Aqua MODIS as a Reference Remote Sensing 12 (8): 1269 [10.3390/rs12081269]

Bhatt, R., D. R. Doelling, A. Angal, et al. X. Xiong, C. Haney, B. R. Scarino, A. Wu, and A. Gopalan. 2020. Response Versus Scan-Angle Assessment of MODIS Reflective Solar Bands in Collection 6.1 Calibration IEEE Transactions on Geoscience and Remote Sensing 58 (4): 2276-2289 [10.1109/tgrs.2019.2946963]

Mu, Q., A. Wu, X. Xiong, and A. Angal. 2020. Assessment of SNPP VIIRS RSB detector-to-detector differences using deep convective clouds and deserts Journal of Applied Remote Sensing 14 (01): 1 [10.1117/1.jrs.14.018503]

Wilson, T., A. Angal, and X. Xiong. 2020. Orbital Path and Spacecraft Attitude Correction for the MODIS Lunar Spatial Characterization IEEE Transactions on Geoscience and Remote Sensing 58 (2): 1063-1073 [10.1109/tgrs.2019.2943254]

Shao, X., T.-C. Liu, X. Xiong, et al. C. Cao, T. Choi, and A. Angal. 2019. Surface Roughness-Induced Spectral Degradation of Multi-Spaceborne Solar Diffusers Due to Space Radiation Exposure IEEE Transactions on Geoscience and Remote Sensing 57 (11): 8658-8671 [10.1109/tgrs.2019.2922070]

Li, Y., X. Xiong, J. W. Mcintire, et al. A. Angal, S. Gusev, and K.-F. Chiang. 2019. Early Calibration and Performance Assessments of NOAA-20 VIIRS Thermal Emissive Bands IEEE Transactions on Geoscience and Remote Sensing 57 (11): 9242-9251 [10.1109/tgrs.2019.2925782]

Xiong, X., A. Angal, K. A. Twedt, et al. H. Chen, D. Link, X. Geng, E. Aldoretta, and Q. Mu. 2019. MODIS Reflective Solar Bands On-Orbit Calibration and Performance IEEE Transactions on Geoscience and Remote Sensing 57 (9): 6355 - 6371 [10.1109/TGRS.2019.2905792]

Tuli, F. T., C. T. Pinto, A. Angal, X. Xiong, and D. Helder. 2019. New Approach for Temporal Stability Evaluation of Pseudo-Invariant Calibration Sites (PICS) Remote Sensing 11 (12): 1502 [10.3390/rs11121502]

Raut, B., M. Kaewmanee, A. Angal, X. Xiong, and D. Helder. 2019. Empirical Absolute Calibration Model for Multiple Pseudo-Invariant Calibration Sites Remote Sensing 11 (9): 1105 [10.3390/rs11091105]

Chang, T., X. Xiong, and A. Angal. 2019. Terra and Aqua MODIS TEB intercomparison using Himawari-8/AHI as reference Journal of Applied Remote Sensing 13 (01): 1 [10.1117/1.jrs.13.017501]

Oudrari, H., J. McIntire, X. Xiong, et al. J. Butler, Q. Ji, T. Schwarting, and A. Angal. 2018. An Overall Assessment of JPSS-2 VIIRS Radiometric Performance Based on Pre-Launch Testing Remote Sensing 10 (12): 1921 [10.3390/rs10121921]

Angal, A., X. Xiong, D. Helder, M. Kaewmanee, and L. Leigh. 2018. Assessing the calibration differences in the reflective solar bands of Terra MODIS and Landsat-7 enhanced thematic mapper plus Journal of Applied Remote Sensing 12 (04): 1 [10.1117/1.jrs.12.044002]

Xiong, X., A. Angal, W. L. Barnes, et al. H. Chen, V. Chiang, X. Geng, Y. Li, K. Twedt, Z. Wang, T. Wilson, and A. Wu. 2018. Updates of Moderate Resolution Imaging Spectroradiometer on-orbit calibration uncertainty assessments Journal of Applied Remote Sensing 12 (03): 1 [10.1117/1.jrs.12.034001]

Angal, A., X. Xiong, A. Wu, X. Geng, and H. Chen. 2018. Improvements in the On-Orbit Response Versus Scan Angle Characterization of the Aqua MODIS Reflective Solar Bands IEEE Transactions on Geoscience and Remote Sensing 56 (3): 1728-1738 [10.1109/tgrs.2017.2767206]

Angal, A., X. Xiong, Q. Mu, et al. D. R. Doelling, R. Bhatt, and A. Wu. 2018. Results From the Deep Convective Clouds-Based Response Versus Scan-Angle Characterization for the MODIS Reflective Solar Bands IEEE Transactions on Geoscience and Remote Sensing 56 (2): 1115-1128 [10.1109/tgrs.2017.2759660]

Chen, H., X. Xiong, A. Angal, and K. A. Twedt. 2017. On-Orbit Characterization of the MODIS SDSM Screen for Solar Diffuser Degradation Estimation IEEE Transactions on Geoscience and Remote Sensing 55 (11): 6456-6467 [10.1109/tgrs.2017.2728520]

Mu, Q., A. Wu, X. Xiong, et al. D. Doelling, A. Angal, T. Chang, and R. Bhatt. 2017. Optimization of a Deep Convective Cloud Technique in Evaluating the Long-Term Radiometric Stability of MODIS Reflective Solar Bands Remote Sensing 9 (6): 535 [10.3390/rs9060535]

Wu, A., X. Geng, A. Wald, A. Angal, and X. Xiong. 2017. Assessment of Terra MODIS On-Orbit Polarization Sensitivity Using Pseudoinvariant Desert Sites IEEE Transactions on Geoscience and Remote Sensing 55 (7): 4168-4176 [10.1109/tgrs.2017.2689719]

Chang, T., X. Xiong, A. Angal, A. Wu, and X. Geng. 2017. Aqua and Terra MODIS RSB Calibration Comparison Using BRDF Modeled Reflectance IEEE Transactions on Geoscience and Remote Sensing 55 (4): 2288-2298 [10.1109/tgrs.2016.2641258]

Angal, A., X. Xiong, and A. Wu. 2017. Monitoring the On-Orbit Calibration of Terra MODIS Reflective Solar Bands Using Simultaneous Terra MISR Observations IEEE Transactions on Geoscience and Remote Sensing 55 (3): 1648-1659 [10.1109/tgrs.2016.2628704]

Bhatt, R., D. R. Doelling, A. Angal, et al. X. Xiong, B. Scarino, A. Gopalan, C. Haney, and A. Wu. 2017. Characterizing response versus scan-angle for MODIS reflective solar bands using deep convective clouds Journal of Applied Remote Sensing 11 (1): 016014 [10.1117/1.jrs.11.016014]

Chen, H., X. Xiong, A. Angal, X. Geng, and A. Wu. 2016. Alternative method of on-orbit response-versus-scan-angle characterization for MODIS reflective solar bands J. Appl. Remote Sens 10 (2): 024004 [10.1117/1.jrs.10.024004]

Chang, T., X. J. Xiong, A. Angal, and Q. Mu. 2016. Assessment of MODIS RSB detector uniformity using deep convective clouds J. Geophys. Res. Atmos. 121 (9): 4783-4796 [10.1002/2015jd024652]

Xiong, X., M. D. King, V. V. Salomonson, et al. W. L. Barnes, B. N. Wenny, A. Angal, A. Wu, S. Madhavan, and D. O. Link. 2015. Moderate Resolution Imaging Spectroradiometer on Terra and Aqua Missions Qian/Optical Payloads for Space Missions 53-89 [10.1002/9781118945179.ch3]

Angal, A., X. Xiong, J. Sun, and X. Geng. 2015. On-orbit noise characterization of MODIS reflective solar bands Journal of Applied Remote Sensing 9 (1): 094092 [10.1117/1.jrs.9.094092]

Xiong, X., A. Angal, J. Sun, T. Choi, and E. Johnson. 2014. On-orbit performance of MODIS solar diffuser stability monitor J. Appl. Remote Sens 8 (1): 083514 [10.1117/1.jrs.8.083514]

Sun, J., X. Xiong, A. A. Angal, H. Chen, and X. Geng. 2014. Time-Dependent Response Versus Scan Angle for MODIS Reflective Solar Bands Geoscience and Remote Sensing, IEEE Transactions on 52 (6): 3159-3174 [10.1109/TGRS.2013.2271448]

Mishra, N., D. Helder, A. A. Angal, J. Choi, and X. Xiong. 2014. Absolute Calibration of Optical Satellite Sensors Using Libya 4 Pseudo Invariant Calibration Site Remote Sens. 6 (2): 1327-1346 [10.3390/rs6021327]

Lyapustin, A. I., Y. Wang, X. Xiong, et al. G. Meister, S. E. Platnick, R. C. Levy, B. A. Franz, S. Korkin, T. Hilker, C. J. Tucker, F. G. Hall, P. J. Sellers, A. Wu, and A. A. Angal. 2014. Scientific impact of MODIS C5 calibration degradation and C6+ improvements Atmos. Meas. Tech. 7 4353-4365 [10.5194/amt-7-4353-2014]

Choi, T., J. Xiong, A. Angal, G. Chander, and J. Que. 2014. Assessment of the spectral stability of Libya 4, Libya 1, and Mauritania 2 sites using Earth Observing One Hyperion Journal of Applied Remote Sensing 8 (1): 083618 [10.1117/1.JRS.8.083618]

Chander, G., A. Angal, T. Choi, and J. Xiong. 2013. Radiometric Cross-Calibration of EO-1 ALI With L7 ETM+ and Terra MODIS Sensors Using Near-Simultaneous Desert Observations IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing 6 (2): 386-399 [10.1109/JSTARS.2013.2251999]

Angal, A., J. Xiong, T. Choi, et al. G. Chander, N. Mishra, and D. L. Helder. 2013. Impact of Terra MODIS Collection 6 on long-term trending comparisons with Landsat 7 ETM+ reflective solar bands Remote Sensing Letters 4 (9): 873-881 [10.1080/2150704X.2013.809496]

Wu, A., J. Xiong, and A. Angal. 2013. Derive a MODIS-Based Calibration for the AVHRR Reflective Solar Channels of the NOAA KLM Operational Satellites IEEE Trans. Geosci. Remote Sensing 51 (3): 1405-1413 [10.1109/TGRS.2012.2220780]

Wu, A., J. Xiong, D. R. Doelling, et al. D. Morstad, A. Angal, and R. Bhatt. 2013. Characterization of Terra and Aqua MODIS VIS, NIR, and SWIR Spectral Bands' Calibration Stability IEEE Trans. Geosci. Remote Sensing 51 (7): 4330-4338 [10.1109/TGRS.2012.2226588]

Chander, G., N. Mishra, D. L. Helder, et al. D. B. Aaron, A. A. Angal, T. Choi, X. Xiong, and D. R. Doelling. 2013. Applications of Spectral Band Adjustment Factors (SBAF) for Cross-Calibration IEEE Trans. Geosci. Remote Sensing 51 (3): 1267-1281 [10.1109/TGRS.2012.2228007]

Helder, D., K. J. Thome, N. Mishra, et al. G. Chander, X. Xiong, A. A. Angal, and T. Choi. 2013. Absolute Radiometric Calibration of Landsat Using a Pseudo Invariant Calibration Site IEEE Transactions on Geoscience and Remote Sensing 51 (3): 1360-1369 [10.1109/TGRS.2013.2243738]

Toller, G., J. Xiong, J. Sun, et al. B. Wenny, X. Geng, J. Kuyper, A. Angal, H. Chen, S. Madhavan, and A. Wu. 2013. Terra and Aqua moderate-resolution imaging spectroradiometer collection 6 level 1B algorithm Journal of Applied Remote Sensing 7 (1): 073557 [10.1117/1.JRS.7.073557]

Angal, A. A., J. Xiong, A. C. Wu, G. Chander, and T. Choi. 2013. Multitemporal Cross-Calibration of the Terra MODIS and Landsat 7 ETM+ Reflective Solar Bands IEEE Transactions on Geoscience and Remote Sensing 51 (4): 1870-1882 [10.1109/TGRS.2012.2235448]

Wu, A., X. Xiong, A. Angal, and W. Barnes. 2011. Evaluation of detector-to-detector and mirror side differences for Terra MODIS reflective solar bands using simultaneous MISR observations International Journal of Remote Sensing 32 (2): 299-312 [10.1080/01431160903464138]

Angal, A., G. Chander, X. Xiong, T. Choi, and A. Wu. 2011. Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors Journal of Applied Remote Sensing 5 (1): 059502-059502-6 [10.1117/1.3613963]

Xiong, X. (., A. Wu, B. Wenny, J. Choi, and A. Angal. 2010. Progress and lessons from MODIS calibration intercomparison using ground test sites Canadian Journal of Remote Sensing 36 (5): 540-552 [10.5589/m10-082]

Angal, A. A., X. Xiong, T. Choi, and G. Chander. 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 Journal of Applied Remote Sensing [10.1117/1.3424910]

Chander, G., X. Xiong, T. Choi, and A. A. Angal. 2010. Monitoring on-orbit calibration stability of the Terra MODIS and Landsat 7 ETM+ sensors using pseudo-invariant test sites Remote Sensing of Environment 114 (4): 925-939 [10.1016/j.rse.2009.12.003]