Welcome to Prof. Daeok Daniel Youn's Homepage!!

Professor Daeok (Daniel) Youn

Professor at the Department of Earth Science Education.

(Go to Korean site: 한글 홈페이지)



His research is briefly summarized below.



Research Area

1. Earth System Modeling (Global Climate and Chemistry Modeling):

Improving the U.K. Earth System Model (UKESM) and a numerical forecasting model (GloSea) by implementing various atmospheric chemistry and aerosol physics schemes

Working with various numerical schemes of atmospheric chemistry and aerosol physics as part of United Kingdom Chemistry and Aerosol (UKCA) included in the HadGEM, a configuration of the UK Met Office Unified Model (UM)

Developed a linking tool (one-way coupled global Climate-Chemistry model) between the “Harvard GEOS-Chem” chemistry and transport model and “NCAR CCSM-3” a climate model

Developed the UIUC 2.5-D chemical-radiative-transport model and the UIUC radiative-transfer model

Evaluated and inter-compared state-of-the-art global Chemistry and Transport Models (CTMs), “NCAR MOZART families” and “NASA GEOS-Combo”, relative to observational datasets

Assessing past and future environmental changes in ozone and PMs related to climate changes (using a global Climate-Chemistry model and a regional WRF-Chem model)

2. Sciences on Atmospheric Chemical Species:

Investigate atmospheric lifetimes and impacts of replacement compounds on ozone (pursuant to Article 6 of the Montreal Protocol) through the numerical calculation of Ozone Depletion Potentials (ODPs)

Investigate direct and indirect effects of replacement compounds on ozone and climate through the numerical calculations of Radiative Forcings and Global Warming Potentials (GWPs)

Study the long-term variability of stratospheric tracers associated with wave activities and residual circulation

Investigate the interaction of atmospheric dynamical processes with atmospheric chemistry

Ozone and PM-2.5 data analysis

3. Environmental assessment modeling

Assess environmental impacts of new sources such as power plants and industrial complexes using atmospheric dispersion models (AERMOD and CALPUFF)





Professional Employment (Appointments)

Department of Earth Science Education, Chungbuk National University

September 2012 – Current

Full professor since 2023

Korea Environment Institute (KEI)

October 2010 – September 2012

Principal Researcher/Research Fellow

Global Environment Center, Korea Institute of Science and Technology (KIST) in Seoul

March 20Research Experiences10 – September 2010

Research Resident (Post-Doctoral position)

Research Institute of Basic Sciences, Seoul National University

March 2008 - February 2010

Senior Research Scientist

Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign (UIUC)

March 2005 - March 2008, November 2001 – November 2002

Hired as Visiting Research Scholar in November 2001

Hired as Visiting Research Scholar (Post-Doc.) in March 2005

Promoted to Research Scientist in August 2006

Department of Atmospheric Sciences, Seoul National University

University Staff (Temporary government position) in 1999

University Staff (Temporary government position) in 2004



Research Experiences



Teaching Experiences



Professional Services



Areas of Expertise

I have extensive research expertise on atmospheric models (Earth System Models, global climate and chemistry-transport models) and analyses of satellite, aircraft, ground-based observational data. The implementation of atmospheric chemistry and aerosol physics into global climate forecasting system of National Meteorological Research Institute for Korean Meteorological Administration and the successful development of enhanced Earth-Environment modeling capability for the Korean government NIER clearly demonstrates my dedication to global climate/environmental science and also my capacity of handling science computer codes and high-performance computers. 15 years ago, I had developed a Global Climate-Chemistry Modeling (GCCM) System for NIER/ME (Ministry of Environment) that links two well-known research models, a state-of-the-art chemistry transport model “Harvard GEOS-Chem” and a climate model “NCAR CCSM-3”. The modeling capability, GCCM, had been assessed relative to extensive measurement data and now highly applied to understand the past and future environmental changes related to climate changes in East Asia as well as all around the World.

Scientifically, I have been focused on the improvement of sub-seasonal prediction over East Asia. Long ago (2003-2010), I have conducted 3-dimensional whole atmosphere model-based calculation of global warming potentials for Halons and ozone depletion potentials for several replacement chemical compounds. Those model-based analyses of climate and ozone metrics have been published at atmospheric chemistry and physics and were reported and cited at WMO-UNEP ozone assessment in 2011.

Among my past research works was a development of advanced atmospheric modeling system of global Krypton-85 and Xenon isotopes background concentrations for improved capability of clandestine uranium separation and nuclear test discrimination. This modeling is for the concept of wide-area detection of clandestine nuclear actions. I believe this modeling capability is eventually applied and used to my country Republic of Korea when proper funding and international cooperation are reached to scientist like me.

I have used various supercomputers at the National Center for Supercomputing Applications (NCSA) at the University of Illinois at Urbana-Champaign and at National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory. During my research activities, I had solved various issues met during the use of NERSC’s and NCSA’s supercomputers by myself or sometimes actively with NCSA’s and NERSC’s consultants.

In summary, my expertise includes

  1. Earth System Modeling and Global Chemistry Climate modeling

  2. Numerical modeling of atmospheric chemistry, physics and dynamics: development of stratospheric dynamics model and improvements of chemistry and radiative transfer models

  3. Long-term transport and variability of stratospheric tracers by wave activity and mass circulation including analyses of satellite data through statistical tools (EOF, LDA, SVD, etc.)

  4. Global climate modeling and chemistry-transport modeling

  5. Global transport modeling of radionuclides such as Krypton-85

  6. Satellite data handling through objective and statistical analysis

  7. Atmospheric dispersion modeling: AERMOD and CALPUFF

  8. Computer expertise on Fortran laSynergistic Activitiesnguage, Interactive Data Language (IDL), shell programming, parallel programming and computing powers including Digital Alpha Unix, SGI IRIX Unix, Linux Alpha, and x86-64 64-bit computer clusters.


Synergistic Activities

I have conducted various researches based on my expertise in observational datasets and in numerical modeling of global atmospheric dynamics and chemistry. My specific research area include 1) Earth System Modeling: Improve sub-seasonal climate predictions by considering impacts of ozone and other climate forcers, 2) Atmospheric lifetime and ozone effects of replacement compounds including ODP and indirect GWP calculations, 2) Global climate modeling coupled with interactive chemistry-aerosol-cloud-radiation, 3) Evaluation and inter-comparison of Earth System Models with observational database such as satellite, aircraft, and sonde data, 4) the long-term variability of stratospheric tracers associated with wave activity and residual circulation, 5) The interaction of atmospheric dynamical processes with atmospheric chemistry and 6) Global transport of radionuclide.

While in the U.S., I conducted projects for companies such as Boeing, Honeywell (now Honeywell/Du Pont) and Albemarble companies. For Boeing, I and a student have developed evaluation tools to see the performance of the state-of-the-art chemistry transport models which were presented in NASA GMI meetings. For Honeywell/DuPont and Albemarble companies, I have conducted assessment studies on the effect of new chemical compounds on the environment, based on the model-based index such as Ozone Depleting Potentials (ODPs) using a global chemistry transport model called as MOZART version 3. For the U.S. EPA, I have conducted another assessment studies on the effects of greenhouse gases on the atmosphere based on the climate metric, Global Warming Potential (GWP).

From October 2010, I have been working at environmental appraisal center of Korea Environment Institute (KEI). Since my major role is the atmospheric assessment of new pollution source, I have studied AERMOD and CALPUFF modeling tools and applied those models to dispersion experiments of air pollutants resulting from building and operations of power plant and industrial complexes. I have been preparing for KEI dispersion modeling system to make AERMOD/CALPUFF correctly applied and used for environment impact assessment.

I had served as an associate editor at KASA (Korean Atmospheric Scientists in America and oversea) for a year March 2007 to March 2008. I helped publish monthly KASA newsletters to Korean community, which shares lives and researches of Korean atmospheric scientists in the U.S.

I thus have extensive experience with the most advanced modeling tools and have made companies’ needs fulfilled through my dedicated works



Publications

43. Youn, D. and Song, H., 2025, Comparisons between UKESM CMIP6 Historical Simulations depending on two Atmospheric Chemistry Schemes: Part I. Global Scale Analysis, Journal of Korean Earth Society, 46(1), 19-34. doi: 10.5467/JKESS.2025.46.1.19 (Korean in English abstract).

42. Seo, J., A. Lee, D.-R. Park, D. Youn, K. H. Kim, C.-E. Park, and J. Y. Kim, 2025, {An evaluation approach to PM2.5 policy effectiveness over South Korea based on a newly proposed scalable spatial decomposition method, Environmental Research Letters, 20{1}, DOI:10.1088/1748-9326/ada2b2, url = {https://dx.doi.org/10.1088/1748-9326/ada2b2},

41. Seo, J., A. Lee, J. Kweon J. B. Kim, D. Youn, K. H. Kim, K. Lee, and J. Y. Kim, 2024, Spatial Correlation Analysis on PM2.5 Local Variability in the Chungcheong Area, J. Korean Soc. Atmos. Environ., vol.40, no.1, pp. 131-148, DOI: 10.5572/KOSAE.2024.40.1.131

40. Song, H., Youn, D.*, Lee, J., and Shin, B., 2024, Possibilities for Improvement in Long-term Predictions of the Operational Climate Prediction System (GloSea6) for Spring by including Atmospheric Chemistry-Aerosol Interactions over East Asia, Journal of Korean Earth Society, 45(1), 1-18. doi: 10.5467/JKESS.2024.45.1.1 (Korean in English abstract).

39. Park, Sungsu, Chanwoo Song, and Daeok Youn, 2022: Relationship between Low-level Clouds and Large-scale Environmental Conditions around the Globe, Korean Earth Sci. Soc., 43(6), 711-736. http://jkess.org/journal/article.php?code=85532 (English)

38. Youn, Daeok, Hyunggyu Song, and Sungsu Park, 2022: An Installation and Model Assessment of the UM, U.K. Earth System Model, in a Linux Cluster, Korean Earth Sci. Soc., 43(6), 609-711. http://jkess.org/journal/article.php?code=85531 (Korean with English abstract)

37. Daeok Youn, Hyunggyu Song, and Johan Lee, 2022: Changes in Meteorological Variables by SO2 Emissions over East Asia using a Linux-based U.K. Earth System Model, Korean Earth Sci. Soc., 43(1), 60−76, https://doi.org/10.5467/JKESS.2022.43.1.60 (Korean with English abstract)

36. Okjin Jung, Yun Seob Moon, Daeok Youn, and Hyunggyu Song, 2022: Time-Series Analysis and Estimation of Prospect Emissions and Prospected Reduction of Greenhouse Gas Emissions in Chungbuk, J. Korean Earth Sci. Soc., 43(1), 41−59, https://doi.org/10.5467/JKESS.2022.43.1.41

35. Youn, D., YH Park, 2021: Climate Change: Characteristics of Storms around Korea, Journal of Coastal Research 114 (SI): 256–260. https://doi.org/10.2112/JCR-SI114-052.1

34. Park, YH, D Youn, 2021: Characteristics of Storm Surge Based on the Forward Speed of the Storm, Journal of Coastal Research 114 (SI), 71-75. https://doi.org/10.2112/JCR-SI114-015.1

33. Kim, JH, SJ Kim, D Youn, MK Kim, JH Kim, J Kim, E Noh, 2021: Impact of North Atlantic-East Asian teleconnections on extremely high January PM10 cases in Korea, Environmental Pollution 290, 118051.

32. Seo, J., Lim, Y. B., Youn, D., Kim, J. Y., and Jin, H. C., 2020: Synergistic enhancement of urban haze by nitrate uptake into transported hygroscopic particles in the Asian continental outflow, Atmos. Chem. Phys., 20, 7575-7594, PDFHTML, https://doi.org/10.5194/acp-20-7575-2020, https://doi.org/10.5194/acp-2019-1171.

31. Song, H., D. Youn, 2020: Comparisons of 1-Hour-Averaged Surface Temperatures from High-Resolution Reanalysis Data and Surface Observations, J. Kor. Earth Sci. Soc. (한국지구과학회지), 41(2), 59-110, HTML (Korean with English abstract).

30. Park, Y. H., D. Youn, 2020: The Study of a New Tidal Power for a Practical Use, Journal of Coastal Research, 95(sp1), 1500-1504, HTML.

29. Kim, J. H., D. Youn, Y. H. Kim, W. J. Shin, 2019: A Study on Characteristics and Countermeasures of Fine Dust Discharge Sources in Cheongju, J. of the assoc. of Kor. Geographers, 8(3), PDF (Korean with English abstract).

28. Ju, J., D. Youn, 2019: Statistically Analyzed Effects of Coal-Fired Power Plants in West Coast on the Surface Air Pollutants over Seoul Metropolitan Area, J. Kor. Earth Sci. Soc. (한국지구과학회지), 40(1), 24-34, HTML (Korean with English abstract).

27. Seo, J., Park, D.-S. R., Kim, J. Y., Youn, D., Lim, Y. B., and Kim, Y., 2018: Effects of meteorology and emissions on urban air quality: a quantitative statistical approach to long-term records (1999–2016) in Seoul, South Korea, Atmos. Chem. Phys., 18, 16121–16137, https://doi.org/10.5194/acp-18-16121-2018, HTML.

26. Youn, D., Y. H. Park, 2018: The Application of Mathematical Analysis to Examine the Beach Erosion along the Upper Texas Coast, Journal of Coastal Research 85 (sp1), 846-850, HTML.

25. Seo J., JY Kim, D Youn, JY Lee, H Kim, YB Lim, Y Kim, HC Jin, 2017: On the multiday haze in the Asian continental outflow: the important role of synoptic conditions combined with regional and local sources, Atmospheric Chemistry and Physics 17 (15), 9311, PDF, HTML.

24. Edward A. Keller, Duane E. Devecchio (지은이), 윤성효, 윤순옥, 김영석, 김지수, 이정현, 정형섭, 김진규, 박덕근, 김교원, 길영우, 윤대옥, 이준이, 하진욱, 이동진 (옮긴이), 2017: Natural Hazards: Earth's Processes as Hazards, Disasters, and Catastrophes, 4th Edition (자연재행와 방재), 시그마프레스, 20177

23. Kim, J. W., D. Youn, 2017: The Generation of Westerly Waves by Sobaek Mountains, J. Kor. Earth Sci. Soc. (한국지구과학회지), 38(1), 24-34, HTML (Korean with English abstract).

22. Park, Y. H., D. Youn, 2017: Applicability of a new tidal power system with reduced environmental impact, KAIS(한국산학기술학회지), 18(12)  (Korean with English abstract).

21. Jang, S., D. Youn, 2016: A teaching material using a laboratory ocean wave experiment to help students understand waves in the ocean, Sci. Edu. Res., 31(2).

20. J. Seo, D. Youn*, J. Y. Kim, and H. Lee, 2014: Extensive spatio-temporal analyses of surface ozone and related meteorological variables in South Korea for 19992010, Atmospheric Chemistry and Physics,Atmos. Chem. Phys., 14, 6395-6415, 2014, doi:10.5194/acp-14-6395-2014 PDF, HTML (*corresponding author)(SCI, IF=5.52, Rank=2.8%).

19. J. Seo, W. Choi, D. Youn,D.-S. R.Park, J. Y. Kim, 2013: Relationship between the stratospheric quasi-biennial oscillation and the spring rainfall in the western North Pacific, Geophysical Research Letters, online published html. (IF=3.505, Rank=top 7.2% (12/167)

18. Lee, H., Olsen, S. C.,Wuebbles, D. J., and Youn, D., 2013: Impacts of aircraft emissions on the air quality near the ground, Atmos. Chem. Phys., 13, 5505-5522, doi:10.5194/acp-13-5505-2013. PDF, html (SCI, IF=5.52, Rank=2.8%)

17. Lee, H., D. Youn*, D. J. Wuebbles, and K. O. Patten, 2012: Diagnostic tools for evaluating quasi-horizontal transport in global-scale chemistry models, J. Geophys. Res., 117, D19302, doi:10.1029/2012JD017644. (*corresponding author). PDF html (IF=3.303, Rank=9.0% (15/167))

16. Moon, B.-K., S.-W. Yeh, R. J.Park, C.-K. Song, and D. Youn, 2013: Effects of the El Nino on Tropospheric Ozone in a Simulation using Climate-Chemistry Model, J. Kor. Earth Sci. Soc. (한국지구과학회지), 34(7), 669-680 (Korean with English abstract).

15. Byung-Kwon Moon, Daeok Youn*, Rokjin J. Park, Sang-Wook Yeh, et al., 2011: Meteorological Responses to a Volcanic Eruption in an Offline Climate-Chemistry Model: A Pilot Study, Asia-Pacific Journal of Atmospheric Sciences, 47(4), 345-351, doi: 10.1007/s13143-011-0021-z (*corresponding author).  PDF  (IF=0.855, Rank=79.4% (54/68))

14. Youn, D., Park, R.J., Jeong, J.I., Moon, B.-K., Yeh, S.-W., Kim, Y.H., Woo, J.-H., Im, E.G., Jeong, J.-H., Lee, S.-J., and Song, C.-K., 2011: Impacts of aerosols on regional meteorology due to Siberian forest fires in May 2003, Atmospheric Environment, 45(7), 1407-1412, doi:10.1016/j.atmosenv.2010.12.028. PDF  html (IF=3.226, Rank=12.4% (24/193))

13. Wuebbles, D. J., Patten, K. O., Wang, D., Youn, D., Martínez-Avilés, M., and Francisco, J. S, 2011: Three-dimensional model evaluation of the Ozone Depletion Potentials for n-propyl bromide, trichloroethylene and perchloroethylene, Atmospheric Chemistry and Physics, 11, 2371-2380, doi: 10.5194/acp-11-2371-2011. PDF (IF=5.309, Rank=1.5% (1/68))

12. Youn, D., Patten, K. O., Wuebbles, D. J., Lee, H., and So, C.-W., 2010: Potential impact of iodinated replacement compounds CF3I and CH3I on atmospheric ozone: a three-dimensional modeling study, Atmospheric Chemistry and Physics, 10, 10129-10144, doi:10.5194/acp-10-10129-2010. PDF (IF=5.309, Rank=1.5% (1/68))

11. Park, R. J., D. Youn, S. H. Yoo, D. S. Han, B. J. Kang, and E. G. Im, 2010: A general parallelization approach to improve computation efficiency in a global chemical transport model (GEOS-Chem), Geochemical Journal, 44(4), 323-329. (IF=0.802, Rank=74.0% (57/77))

10. Park, R. J., M. J. Kim, J. I. Jeong, D. Youn, and S. Kim, 2010: A contribution of brown carbon aerosol to the aerosol light absorption and its radiative forcing in East Asia, Atmospheric Environment, 44, 1414-1421, doi:10.1016/j.atmosenv.2010.01.042. (IF=3.226, Rank=12.4% (24/193))

9. Youn, D., K. Patten, J.-T. Lin, and D. Wuebbles, 2009: Explicit Calculation of Indirect Global Warming Potentials for Halons using Atmospheric Models, Atmospheric Chemistry and Physics, 9, 8719-8733, doi:10.5194/acp-9-8719-2009. PDF(IF=5.309, Rank=1.5% (1/68))

8. Park, R. J., J. I. Jeong, D. Youn, 2009: A study of the Effects of Siberian Wildfires on Ozone Concentrations over East Asia in Spring 2003, Atmosphere (대기), 19 (3), 227-296 (Korean with English abstract)

7. Wuebbles, D. J., D. Youn, K. O. Patten, D. Wang, and M. Martinez-Aviles, 2009: Metrics for Ozone and Climate: Three-dimensional Modeling Studies of Ozone Depletion Potentials and Indirect Global Warming Potentials. In Twenty Years of Ozone Decline, C. Zerefos, G. Contopoulos and G. Skalkeas, editors, Springer Publishing, Dordrecht, The Netherlands, doi: 10.1007/978-90-481-2469-5.

6. Lin, J.-T., D. Youn, X.-Z. Liang, and D. J. Wuebbles, 2008: Global model simulation of summertime U.S. ozone diurnal cycle and its sensitivity to PBL mixing, spatial resolution, and emissions, Atmospheric Environment, 42(36), 8470-8483, doi:10.1016/j.atmosenv.2008.08.012. PDF html (IF=3.226, Rank=12.4% (24/193))

5. Jeong, J. I., R. J. Park, and D. Youn, 2008: Effects of Siberian forest fires on air quality in East Asia during May 2003 and its climate implication, Atmospheric Environment, 42(39), 8910-8922, doi:10.1016/j.atmosenv.2008.08.037. PDF, html (IF=3.226, Rank=12.4% (24/193))

4. Li, Y., K. O. Patten, D. Youn, and D. J. Wuebbles, 2006: Potential impacts of CF3I on ozone as a replacement for CF3Br in aircraft applications. Atmospheric Chemistry and Physics, 6, 4559-4569, doi:10.5194/acp-6-4559-2006. PDF html(IF=5.309, Rank=1.5% (1/68))

3. Youn, D., W. Choi, H. Lee, and D. J. Wuebbles, 2006: Interhemispheric differences in changes of long-lived tracers in the middle stratosphere over the last decade. Geophysical Research Letters, 33, L03807, doi:10.1029/2005GL024274. PDF (IF=3.505, Rank=top 7.2% (12/167)

2. Youn, D., D. J. Wuebbles, and M. B. Kalinowski, 2006: Global modeling of atmospheric Krypton-85 concentrations, INESAP Information Bulletin, No. 27, December 2006, pp. 13-16.

1. Choi, W., and D. Youn, 2000: Effects of Physical and Numerical Schemes on Model-Calculated Ozone Distribution in the Stratosphere. Korean J. Atm. Sci., 3, 39-52 (Full paper in English).