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Xiaoguang (Richard) Xu

Profile photo for Xiaoguang (Richard) Xu

Research Associate Professor

Physics
Earth and Space Institute
Goddard Earth Sciences Technology and Research (GESTAR) II

Physics 328

Education

Ph D University of Nebraska-Lincoln 2015

MS Lanzhou University 2008

BS Lanzhou University 2005

xxu@umbc.edu

About

My research integrates advanced satellite remote sensing, Earth system modeling, and machine learning, with a focus on atmospheric aerosol and cloud, to address critical challenges in climate change, air quality, and environmental health. I specialize in the fusion of hyper-spectral and polarimetric data (e.g., from NASA PACE, TEMPO satellites) to characterizeatmospheric aerosols and their impacts on urban and coastal environments. My work spans in the areas of: (1) developing next-generation radiative transfer models (UNL-VRTM) and physics-informed machine learning algorithms for efficient satellite data retrieval; (2) utilizing data assimilation to constrain aerosol sources and their climate forcing; and (3) applying these tools to interdisciplinary studies linking atmospheric composition to public health and climate resilience.

Research Interests

Chemistry transport modeling; radiative transfer; satellite remote sensing of aerosols

Teaching Interests

Climate modeling; Physical meteorology; atmospheric physics and chemistry; Remote Sensing

Selected Classes
  • Fall 2021 PHYS 335 – Physics and Chemistry of the Atmosphere

Contracts, Fellowships, Grants, and Sponsored Research

Xu, Xiaoguang (Principal). “Constraining Dust Refractive Index and Direct Radiative Effect in Long Wave Using Paired Sounder-Imager Sensors,” Grant (Not Funded). Sponsored By: NASA: TASNPP.

Xu, Xiaoguang (Principal), McBride, Brent (Co-Principal), Martins, Jose V (Co-Principal). “Establishing Altiplano Benchmark Sites for Vicarious Calibration of Satellite Polarimeters,” Sponsored Research (Currently Under Review). Sponsored By: NASA.

Xu, Xiaoguang (Principal). “Snapshot spectral imaging CubeSat for dense multi-angle measurements,” SubContract (Not Funded). Sponsored By: NASA: INVEST.

Xu, Xiaoguang (Co-Principal). “Sensitivity analysis and recovery of dust emissions from spectral climate signals,” Grant (Funded). Sponsored By: NASA: ACSCS, PI: Dr. Jun Wang. (Nov 1, 2014 – Oct 31, 2017).

Xu, Xiaoguang (Co-Principal). “Multi-phase inversion of aerosol sources using MODIS, MISR, OMI, and AERONET data and the GEOS-Chem adjoint,” SubContract (Funded). Sponsored By: NASA: ACMAP, PI: Dr. Daven Henze. (Feb 17, 2017 – Feb 16, 2020).

Xu, Xiaoguang (Principal). “Retrieval of Aerosol Vertical Distributions with Measurements from O2 A/B Bands and Polarimetric Data from Blue Bands: Algorithm Development and Synergistic Analysis,” Grant (Funded). Sponsored By: NASA: Remote Sensing Theory for Earth Science. (Oct 15, 2020 – Oct 14, 2024).

Xu, Xiaoguang (Principal), Smith, Rachel (Co-Principal), Sienkiewicz, Noah (Co-Principal). “Determining Atmospheric Aerosol Properties from the UMBC HARP CubeSat in Space,” Grant Sponsored By: UMBC. (Jun 1, 2021 – May 31, 2023).

Xu, Xiaoguang (Co-Principal), Wang, Jun (Principal). “EPIC Hourly Aerosol Optical Centroid Height (AOCH) product: mapping the diurnal variation of smoke and dust vertical distributions for air quality and climate studies,” Grant (Funded). Sponsored By: NASA. (Mar 9, 2022 – Mar 8, 2026).

Xu, Xiaoguang (Principal), Smith, Rachel (Supporting). “Model Development for Polarimetric Remote Sensing of Clouds in the Thermal Infrared,” Grant Sponsored By: UMBC CIDER. (Jun 1, 2023 – Jun 30, 2026).

Xu, Xiaoguang (Principal), Knobelspiesse, Kirk (Co-Principal). “Travel support for students and early-career researchers to attend the 4th Advancement of POLarimetric Observations (APOLO-2024) Conference,” Grant (Funded). Sponsored By: NASA. (Aug 1, 2024 – Jul 31, 2025).

Puthukkudy, Anin (Principal), Martins, Jose V. (Supporting), Xu, Xiaoguang (Supporting), McBride, Brent (Supporting). “An AI-driven approach for retrieving aerosol and surface properties from HARP family of multi-angle polarimeter measurements,” Sponsored Research (Funded). Sponsored By: UMBC. (Jan 1, 2025 – Jun 30, 2026).

Puthukkudy, Anin (Principal), Xu, Xiaoguang (Co-Principal), Wang, Jianwu (Co-Principal). “CAIG: Accelerating Radiative Transfer for Aerosol Satellite Remote Sensing Test Beds using Physics-Informed Neural Network,” Sponsored Research (Currently Under Review). Sponsored By: NSF. (Jan 1, 2026 – Dec 31, 2028).

McBride, Brent (Principal), Xu, Xiaoguang (Co-Principal), Puthukkudy, Anin (Co-Principal), Smith, Jennifer (Supporting), Carter, Corey (Supporting), Krauss, Sara (Supporting), Toth, Todd (Supporting), Mittapalli, Kavita (Supporting), Sayer, Andrew (Supporting). “PACE Activation,” Sponsored Research (Currently Under Review). Sponsored By: NASA. (Sep 1, 2026 – Aug 31, 2031).

Intellectual Contributions

Smith, Rachel E., McBride, Brent, Xu, Xiaoguang, Puthukkudy, Anin, Sienkiewicz, Noah, Cieslak, Jan D., Remer, Lorraine A., Borda, Roberto F., Martins, Jose V. (2025). . Frontiers in Remote Sensing.

Sienkiewicz, Noah, Martins, Jose V., McBride, Brent, Xu, Xiaoguang, Puthukkudy, Anin, Smith, Rachel, Borda, Roberto F. (2025). HARP2 Pre-Launch Calibration Overview: The Effects of a Wide Field of View. Atmospheric Measurements and Technology.

Martins, Jose V., Borda, Roberto F., Puthukkudy, Anin, Xu, Xiaoguang, SIenkiewicz, Noah, Smith, Rachel, McBride, Brent, Dubovik, Oleg, Remer, Lorraine A. (2024). . 13192 SPIE Sensors, Systems, and Next-Generation Satellites XXVIII.

McBride, Brent, Martins, Jose V., Cieslak, Jan D., Borda, Roberto F., Puthukkudy, Anin, Xu, Xiaoguang, Sienkiewicz, Noah, Cairns, Brian, de Melo Jorge Barbosa, Henrique. (2024). Pre-launch calibration and validation of the Airborne Hyper-Angular Rainbow Polarimeter (AirHARP) instrument. 19. 17 5709-5729 ATMOSPHERIC MEASUREMENT TECHNIQUES.

McCourt, Natalie, McBride, Brent, Xu, Xiaoguang, Puthukkudy, Anin, Martins, Jose V. Multi-angle and polarimetric characterization of various Earth surface types with the PACE HARP2 polarimeter. SPIE.

McBride, Brent, Xu, Xiaoguang, Puthukkudy, Anin, Gao, Meng, Rajapakshe, Chamara, Knobelspiesse, Kirk, Martins, Jose V. Science Products as Feedback for Calibration: Examples from the HARP2 polarimeter on NASA’s PACE mission. Utah: CALCON.

McBride, Brent, Venkatesulu, Erica, Borda, Roberto F., Puthukkudy, Anin, Xu, Xiaoguang, Patt, Frederick S., Lee, Shihyan, Meister, Gerhard, Knobelspiesse, Kirk, Cairns, Brian, Martins, Jose V. Polarimetric mapping of the lunar surface with the Hyper-Angular Rainbow Polarimeter 2 (HARP2) on the NASA PACE mission. Applied Optics.

Presentations

Martins, Jose V. (Author), Borda, Roberto F. (Author), Sienkiewicz, Noah (Author), McBride, Brent (Author), Xu, Xiaoguang (Author), Puthukkudy, Anin (Author & Presenter), Smith, Rachel E. (Author), Remer, Lorraine A (Author). CalCon 2025. Oral Presentation. "The First Year of HARP2/PACE Performance Based on its Ground and On-Orbit Characterization," SDL UTAH. (Jun 10, 2025).

Puthukkudy, Anin (Author & Presenter), Martins, Jose V. (Author), Xu, Xiaoguang (Author), McBride, Brent (Author). CalCon 2025. Oral Presentation. "On-Orbit Performance Assessment of the HARP2 Multi-Angle Polarimeter on the NASA PACE Mission: Intercomparison with OCI and SPEXOne Instruments," SDL UTAH. (Jun 10, 2025).

McBride, Brent (Author & Presenter), Martins, Jose V. (Author), Xu, Xiaoguang (Author), Puthukkudy, Anin (Author), Borda, Roberto F (Author). EGU 2025. Oral Presentation. "The First Year of the Hyper-Angular Rainbow Polarimeter (HARP2) on the NASA PACE mission: Performance, Science, and Synergy," EGU. (Apr 28, 2025).

Puthukkudy, Anin (Author & Presenter), Martins, Jose V., Xu, Xiaoguang, Litvinov, Pavel, Fuertes, David, García Gómez, Alejandro, Lopatin, Anton, Matar, Christian, Antuña-Sánchez, Juan Carlos, Sienkiewicz, Noah, Dubovik, Oleg. AGU Fall Meeting 2024. Oral Presentation. "Retrieving Aerosol and Surface Products Using Multi-Pixel approach from PACE Polarimeter HARP2 Observations with GRASP," AGU. (Dec 1, 2024).

Puthukkudy, Anin (Author & Presenter), Martins, Jose V., Xu, Xiaoguang, Sienkiewicz, Noah, McBride, Brent, Litvinov, Pavel, Fuertes, David, Dubovik, Oleg. APOLO 2024. Oral Presentation. "Aerosol and Surface Products from PACE Polarimeter HARP2 Observations using GRASP," (Nov 1, 2024).

Martins, Jose V., Dubovik, Oleg, Fuertes, David, Giralda, Marcos, Remer, Lorraine A., Xu, Xiaoguang, McBride, Brent. SPIE Sensors and Imaging. Oral Presentation. "The measurement of aerosol and gases from space for climate and air pollution application," (Sep 16, 2024).

Martins, Jose V., Borda, Roberto F., Sienkiewicz, Noah, Xu, Xiaoguang, Puthukkudy, Anin (Author & Presenter), Smith, Rachel E., McBride, Brent, Dubovik, Oleg, Remer, Lorraine A. SPIE Sensors and Imaging. Oral Presentation. "First Results and On-Orbit Performance of the Hyper-Angular Rainbow Polarimeter on the PACE Satellite," (Sep 16, 2024).

Martins, Jose V., Xu, Xiaoguang. NOAA/ESSIC Seminar Series. Seminar. "First results and on-orbit performance of the Hyper-Angular Rainbow Polarimeter (HARP2) on the PACE satellite," NOAA. (Jan 1, 2024).

Sienkiewicz, Noah (Author & Presenter), Martins, Jose V. (Author), Borda, Roberto F. (Author), Xu, Xiaoguang (Author), Puthukkudy, Anin (Author), Smith, Rachel (Author). ELS 2023. Poster. "Advancements on the Hyper-Angular Rainbow Polarimeter (HARP) polarization characterization during NASA Plankton Aerosol and Ocean Ecosystem (PACE) pre-launch calibration," (May 18, 2023).