Contact Us:

David Throckmorton
Vice President of Research

James Closs
Director of Research Program Development

Carly Bosco
Director of NASA Langley Programs

Peter McHugh
Director of FAA Programs

Samantha Austin
Program Manager, Advanced Composites Consortium Integration

Hyun Deok Choi

Tel: +1 (757) 864-9643; FAX:  +1 (757) 864-6326

Email: or

Research Interests

  • Impact of global change on air quality and tropospheric chemistry
  • The atmospheric transport, transformations, and fate of hydrophobic organic chemicals, metals, and ions in a wide array of environmental systems
  • Explore the dynamic relationships between fire regimes, weather and climate using ground-based, satellite and airborne data
  • Pollutant exchange through wet deposition, dry deposition and air-surface / air-water exchange between earth’s surface and the atmosphere


  • Ph.D. (2007), Civil and Environmental Engineering, Clarkson University, New York
  • M.S. (2003), Environmental Engineering, Yonsei University, Korea
  • B.S. (2001), Environmental Engineering, Yonsei University, Korea

Current Research

  • Generating a biomass burning smoke plume verification and validation dataset coincident with CALIOP data for the CALIPSO science team using existing NASA and NOAA satellite data and products.

This project focuses on the development of a biomass burning (BB) smoke plume data set that can be used to enhance existing algorithms and to verify and validate (V&V) smoke in the Cloud Aerosol Lidar Orthogonal Polarization (CALIOP) curtains. NASA and NOAA satellite, aircraft, and in-situ observations will be used to develop a unique product that will be used to refine, V&V the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Vertical Aerosol Feature Mask and smoke sub-type product.  Innovative uses of the product derived in this work include processes that are often thought of as land-based but are intricately linked to the atmosphere. In addition, the V&V data could be used to assess the potential spectral differences that exist between ecosystem-dependent young (near field, concentrated) and aged (diluted) smoke.

  • Linking NASA Satellite Data and Science to Enhance Fire Emissions with the EPA’s National Emissions Inventory: Connecting Models to Plume Injection Height Data and Verifying Modeled Emissions Estimates.

This project focuses on the application of NASA satellite, aircraft, and in-situ observations to develop unique products that are designed to enhance the existing National Emissions Inventory (NEI) and Community Multi-scale Air Quality (CMAQ) model, thereby working to improve human health and the environment. The NEI and CMAQ are primary decision support tools used for critical environmental management and policy activities including regulation setting and regional strategy development for attainment of National Ambient Air Quality Standards (NAAQS). Biomass burning is one of the primary causes of elevated airborne particulate matter, ozone precursors and regional haze. The final intend of this project is to complete the analysis of selected cases that benchmark CALIOP plume height data within CMAQ, and we anticipate submitting a minimum of two manuscripts, which are currently in development. Additionally, we will advertise this new product at appropriate scientific venues.

  • Development of regional and global chemical transport model evaluation methods using trace gas and aerosol satellite data, and transfer of operational code to U.S. EPA Remote Sensing Information Gateway Application.

Effective air quality management requires air quality (AQ) management organizations to acquire, analyze, and develop useful data products and policy relevant information from complex sets of data. Satellite data (physical and atmospheric composition) and numerical model output are among the most complex data sets to analyze and present in a user-ready and policy-relevant manner. In addition, analysis techniques to translate the data for increased use by AQ management agencies are often done as “one-off” analyses and not developed in a consistent manner for use by the larger AQ community. By employing the Air Quality Cyberinfrastructure Best Practices developed under the EPA-funded CyAir Project (, and demonstrated through the EPA Remote Sensing Information Gateway (RSIG –, this task is focused on the development of technically correct methods to evaluate chemical transport models using relevant satellite data products. This work is being conducted in support of NASA Air Quality Applied Science Team, and to support the creation of new interoperable systems to support delivery and presentation of AQAST and NASA data products in a user-ready and policy-relevant manner.

  • Emission, transport, deposition, and impacts of biomass burning derived black carbon on the Greenland Ice Sheet.

The Greenland Ice Sheet(GIS) is under going changes with potentially profound impacts on global sea level. DuringJuly2012, a particularly unusual event occurred when NASA sensors showed that nearly 98.6% of the ice sheet experienced melting, up from a prior satellite-era record of 52%(Ngheim et al., 2012).In the weeks prior to the 2012 melt, MODIS observations indicated that overall ice sheet albedo was the lowest on record. Preliminary analysis of snow samples collected last summer on the GIS near Summit Station shows evidence that black carbon(BC) concentrations were strongly enhanced and may have significantly contributed to the low albedo. Along with high levels of black carbon the samples show significant amounts of ammonia, indicating the BC was sourced from biomass burning – likely from unusually active forest fires in Eurasia and North America. Preliminary remote sensing data also shows that the Eurasian fires were of sufficient intensity to inject smoke plumes high into the atmosphere, and that transport conditions were favorable for moving the material toward Greenland. We propose to take a multi-disciplinary team approach to use the 2012 melt and fire events,and events which may occur in 2013,to synthesize a new, quantitative understanding of the emission, transport, deposition, and radiative impact of BC from large biomass burning events on the GIS. Modeling efforts initialized with the observed plume configurations will be used to estimate BC transport to and deposition on the GIS from specific fire events and compared with deposition observed in snow samples. Improved models will be used to quantitatively assess the impact of large scale biomass burning on radiative forcing and melt production on the GIS during summer 2012 and 2013 melt seasons.

  • Effects of Global Change on Asian Pollution Outflow and Long-Range Transport

The objectives of this research is to study the uncertainties in model predictions due to the use of different input meteorological fields by incorporating output from the NOAA GFDL AM3 model into the NASA Global Modeling Initiative (GMI) modeling framework and eventually to investigate the effects on Asian ozone (O3) pollution outflow and long-range transport from global changes in climate and anthropogenic emissions of O3 precursors. The GMI framework also allows us to assess the AM3 meteorological fields through inter-comparison with those from other major global climate models or data assimilation systems.

Refereed Publications

  • Hyun-Deok Choi, Jiaoyan Huang, Sunoma Mondal, and Thomas M. Holsen. “Variation in concentrations of three mercury (Hg) forms at a rural and a suburban Site in New York State” Sci. Total Environ. 2013, 448, 96 – 106.
  • Jiaoyan Huang, Hyun-Deok Choi, Matthew S. Landis, Thomas M. Holsen. “An Application of Passive Samplers to Understand Atmospheric Mercury Concentration and Dry Deposition Spatial Distributions.”J. Environ. Monitor 2012, 14, 2976-2982.
  • Yong-Seok Seo, Yong-Ji Han, Hyun-Deok Choi, Thomas M. Holsen, and Seung-Muk Yi. “Characteristics of total mercury (TM) wet deposition: Scavenging of atmospheric mercury species” Atmos. Environ.2012, 49, 69-76.
  • Jiaoyan Huang, Philip K. Hopke, Hyun-Deok Choi, James R. Laing, Huailue Cui, Tiffany J. Zananski, Sriraam Ramanathan, Chandrasekaran, Oliver V. Rattigan, and Thomas M. Holsen. “Mercury (Hg) Emissions from Domestic Biomass Combustion for Space Heating” Chemosphere 2011, 84(11), 1694-1699.
  • Jiaoyan Huang, Hyun-Deok Choi, Thomas M. Holsen, and Philip K. Hopke. “Ambient mercury sources in Rochester, NY: Resrults form principle component analysis (PCA) of mercury monitoring network data” Environ. Sci. Technol. 2010, 44(22), 8441-8445.
  • Hyun-Deok Choi, James J. Pagano, Michael S. Milligan, Philip K. Hopke, Steven Skubis, and Thomas M. Holsen. “Polychlorinated Biphenyls (PCB) Air Concentrations in the Lake Ontario Region: Trends and Potential Sources” Atmos. Environ. 2010, 44(26), 3173-3178.
  • Hyun-Deok Choi and Thomas M. Holsen. “Gaseous Mercury Emissions from Unsterilized and Sterilized Soils: The Effect of Temperature and UV Radiation” Environ. Pollut. 2009, 157(5), 1673-1678.
  • Hyun-Deok Choi and Thomas M. Holsen. “Gaseous Mercury Emissions from Forest Floor of the Adirondacks.” Environ. Pollut. 2009, 157(2), 592-600.
  • Pranesh Selvendiran, Hyun-Deok Choi, Charles T. Driscoll, Mario R. Montesdeoca, and Thomas M. Holsen. Mercury Dynamics and transport in two Adirondack Lakes. Limnol. Oceanogr. 2009, 54(2), 413-427.
  • Hyun-Deok Choi, Thomas M. Holsen, and Philip K. Hopke. “Atmospheric Mercury (Hg) in the Adirondacks: Concentrations and Sources” Environ. Sci. Technol. 2008, 42(15), 5644-5653.
  • Hyun-Deok Choi, Timothy J. Sharac, and Thomas M. Holsen. “Mercury Deposition in the Adirondacks: A Comparison between Precipitation and Throughfall.” Atmos. Environ. 2008, 42(8), 1818-1827.




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