Resident at NASA Langley Research Center
MS401A, Hampton, VA 23681
Tel: 757-864-5512, Fax: 757-864-6326
Email: ychoi@nianet.org
Research Interests
· Measurement of the high precision, in-situ CO2 concentration aboard NASA DC-8
· Development of the CO2 measurement systems for the validation flights for the newly evolving remote CO2 sensors
· Data Analysis for the tropospheric CO2 measurement for the aircraft missions
· C-13 and C-14 isotope mass spectrometric measurement and data analysis
Current Research
· DC-8 Aircraft measurements and data analysis of atmospheric CO2, ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) field mission was conducted with three NASA aircraft (DC-8, P-3, and B200) during the spring and summer of 2008 time period. ARCTAS includes studies for the California Air Resources Board (CARB) as part of a scientific collaborative effort. Our AVOCET (Atmospheric Vertical Observation of CO2 in the Earth’s Troposphere) in-situ CO2 measurement system aboard DC-8 carried out successfully the mission with other highly specialized instruments. Phase-A and Phase-B of INTEX (Intercontinental Chemical Transport Experiment), ARCTAS and CARB mission data analysis has been doing and the results will contribute to the several objectives, which are 1) large-scale characterization of the spatiotemporal distributions of atmospheric CO2 needed to resolve seasonal and annual CO2 budget, 2) quantify North American CO2 source/sinks and contributions from Asian emissions 3) evaluate inverse techniques that assimilate surface observations to derive regional to continental scale CO2 flux estimates 4) provide integrated measures of atmospheric column amounts from vertical soundings for retrieval algorithm development and validation of remotely-sensed data products, 5) offer an independent assessment of anthropogenic emission inventories (bottom-up approaches), and 6) quantify and trace the pollution source with carbon isotopes (C-13 and C-14).
· Validation for newly evolving remote CO2 sensors, ACCLAIM (Advance Carbon and Climate Laser Intercontinental Mission) and ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) field mission has been performed during the August through October of 2008 to investigate the feasibility of measuring total column CO2 from space with NASA LaRC in-situ CO2 measurement team in partnership with ITT and University of New Hampshire. A series of field experiments has been conducted to validate the performance of laser instrument with in-situ CO2 instrument. The newly developed fast and high precision in-situ CO2 measurement systems were integrated at NASA UC-12B aircraft and have been flying successfully for ASCENDS CAL/VAL field mission.
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Publications
· T. Refaat, S. Ismail, G. Koch, Y. Choi, et al., 2010, Backscatter 2mm Lidar Validation for Atmospheric CO2 DIAL Applications, In review at IEEE Transactions on Geoscience and Remote Sensing.
· S. Vay, S. Tyler, Y. Choi, et al., 2009, Sources and transport of D14C on CO2 within the Mexico City Basin and vicinity, Atmos. Chem. Phys., 9, 4973-4985.
· Yonghoon Choi, Stephanie Vay, and many others, 2008, Characteristics of the atmospheric CO2 signal as observed over the conterminous United States during INTEX-NA, Journal of Geophysical Research – Atmospheres, Vol. 113, D07301, doi:10.1029/2007JD008899.
· J. E. Campbell, S. A. Vay, Y. Choi, and many others, 2007, Analysis of anthropogenic CO2 singal in ICARTT using a regional chemical transport model and observed tracers, Tellus, 59B, doi:10.1111/j.1600—889.2006.00239.x
· Yonghoon Choi and Yang Wang, 2004, Dynamics of carbon sequestration in a Coastal wetland using radiocarbon measurements, Global Biogeochemical Cycles, 18, GB4016, doi:10.1029/2004GB002261
· E. Browell, J. Dobler, S. Kooi, Y. Choi, et al., 2010, 25th International Laser Radar Conference, Airborne validation of laser remote measurements of atmospheric carbon dioxide, Saint Petersburg, Russia, July 5-9, 2010.
· S. Vay, Y. Choi, et al., 2009, AGU (American Geophysical Union) Fall Meeting, Patterns of CO2 and radiocarbon across high northern latitudes during IPY 2008.
· Y. Choi, S. Vay, Jung-Hun Woo, et al., 2009, ICDC8 (8th International Carbon Dioxide Conference), Spatio-temporal variability of atmospheric CO2 as observed from in-situ measurements over North America during NASA Field Campaigns (2004-2008).
· Y. Choi, S. Vay, et al., 2009, 2nd NACP All-investigators Meeting, Spatiotemporal distributions of atmospheric CO2 from high resolution in-situ measurements over North America during NASA Field Campaigns (2004-2008).
· K. Vadrevu, Y. Choi, S. Vay, 2009, AGU (American Geophysical Union) Fall Meeting, Spatial variations in atmospheric CO2 concentrations during the ARCTAS-CARB 2008 Summer Campaign.