EGU24-17722, updated on 12 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Diurnal characteristics of the NO2 columns observed over Asia from Geostationary Environment Monitoring Spectrometer (GEMS)

Hanlim Lee1, Junsung Park1,2, Hyunkee Hong3, Jhoon Kim4, Hyo-Jung Lee5, Yeonjin Jung1, Michel Van Roozendael6, Caroline Fayt6, Rokjin Park7, Siwan Kim4, Myong-Hwan Ahn8, Daniel J. Jacob9, Daewon Kim1, Wonei Choi1, Won-Jin Lee3, Dong-Won Lee3, Thomas Wagner10, Andreas Richter11, Nickolay A. Krotkov12, and Lok N. Lamsal12
Hanlim Lee et al.
  • 1Division of Earth Environmental System Science, Major of Spatial Information Engineering, Pukyong National University, Busan, Republic of Korea
  • 2Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA
  • 3National Institute of Environmental Research, Incheon, Republic of Korea
  • 4Department of Atmospheric Sciences, Yonsei University, Seoul, Republic of Korea
  • 5Department of Atmospheric Sciences, Pusan National University, Busan, Republic of Korea
  • 6Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
  • 7School of Earth and Environmental Sciences, Seoul national University, Seoul, Republic of Korea
  • 8Department of Climate and Energy Systems Engineering/Social Economy, Ewha Womans University, Seoul, Republic of Korea
  • 9School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, USA
  • 10Max-Planck Institute for Chemistry (MPI-C), Mainz, Germany
  • 11Institute of Environmental Physics (IUP-UB), University of Bremen, Bremen, Germany
  • 12Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA

Nitrogen oxides are key gas components of emissions from fossil-fuel combustion, are known to degrade air quality and have adverse health effects. Diurnal NO2 observations are crucial for enhancing our understanding of NOx emissions, lifetime, and chemistry. Geostationary Environment Monitoring Spectrometer (GEMS) has been providing hourly observations NO2 columns over Asia since November 2020. The latest NO2 version 3 products have significantly improved with updated air mass factors (AMFs) and the separation of stratospheric and tropospheric columns. To identify the dependency of the distribution on the time of the day, we investigated hourly tropospheric NO2 cycles of cities over Asia using GEMS measurements for the first time. The cities show similar diurnal concentration patterns with peaks in the morning and troughs in the afternoon, although the amplitude and specific times vary by city. The reduction rate of NO2 was influenced by the temporal dependence of the spatial distribution within and around cities. We also observed distinct NO2 diurnal patterns in certain industrial areas and cities where NOx emissions are thought to be controlled. To explain the location-dependent variations of the tropospheric NO2 columns, we compared the diurnal NO2 cycles obtained from the GEMS measurement with WRF-Chem models for some cities. In addition, estimated top-down NOx emissions from GEMS measurements are presented in comparison with bottom-up emission inventory, showing a smaller difference compared to the top-down emission from TROPOMI measurements. It is expected that hourly top-down NOx emissions using GEMS measurements can provide a useful information in improving the future performance of air quality modeling.

How to cite: Lee, H., Park, J., Hong, H., Kim, J., Lee, H.-J., Jung, Y., Roozendael, M. V., Fayt, C., Park, R., Kim, S., Ahn, M.-H., Jacob, D. J., Kim, D., Choi, W., Lee, W.-J., Lee, D.-W., Wagner, T., Richter, A., Krotkov, N. A., and Lamsal, L. N.: Diurnal characteristics of the NO2 columns observed over Asia from Geostationary Environment Monitoring Spectrometer (GEMS), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17722,, 2024.