Articles | Volume 17, issue 16
Atmos. Chem. Phys., 17, 10125–10141, 2017
Atmos. Chem. Phys., 17, 10125–10141, 2017

Research article 30 Aug 2017

Research article | 30 Aug 2017

Intercomparison of NOx emission inventories over East Asia

Jieying Ding1,2, Kazuyuki Miyazaki3,4, Ronald Johannes van der A1,5, Bas Mijling1, Jun-ichi Kurokawa6, SeogYeon Cho7, Greet Janssens-Maenhout8, Qiang Zhang9, Fei Liu1, and Pieternel Felicitas Levelt1,2 Jieying Ding et al.
  • 1Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
  • 2Delft University of Technology, Delft, the Netherlands
  • 3Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001, Japan
  • 4Jet Propulsion Laboratory-California Institute of Technology, Pasadena, USA
  • 5Nanjing University of Information Sciences and Technology, Nanjing, China
  • 6Asia Center for Air Pollution Research, Niigata, 950-2144, Japan
  • 7Department of Environmental Engineering, Inha University, Incheon, South Korea
  • 8Directorate for Energy, Transport and Climate, Joint Research Centre, Ispra, Italy
  • 9Department of Earth System Science, Tsinghua University, Beijing, 100084, China

Abstract. We compare nine emission inventories of nitrogen oxides including four satellite-derived NOx inventories and the following bottom-up inventories for East Asia: REAS (Regional Emission inventory in ASia), MEIC (Multi-resolution Emission Inventory for China), CAPSS (Clean Air Policy Support System) and EDGAR (Emissions Database for Global Atmospheric Research). Two of the satellite-derived inventories are estimated by using the DECSO (Daily Emission derived Constrained by Satellite Observations) algorithm, which is based on an extended Kalman filter applied to observations from OMI or from GOME-2. The other two are derived with the EnKF algorithm, which is based on an ensemble Kalman filter applied to observations of multiple species using either the chemical transport model CHASER and MIROC-chem. The temporal behaviour and spatial distribution of the inventories are compared on a national and regional scale. A distinction is also made between urban and rural areas. The intercomparison of all inventories shows good agreement in total NOx emissions over mainland China, especially for trends, with an average bias of about 20 % for yearly emissions. All the inventories show the typical emission reduction of 10 % during the Chinese New Year and a peak in December. Satellite-derived approaches using OMI show a summer peak due to strong emissions from soil and biomass burning in this season. Biases in NOx emissions and uncertainties in temporal variability increase quickly when the spatial scale decreases. The analyses of the differences show the importance of using observations from multiple instruments and a high spatial resolution model for the satellite-derived inventories, while for bottom-up inventories, accurate emission factors and activity information are required. The advantage of the satellite-derived approach is that the emissions are soon available after observation, while the strength of the bottom-up inventories is that they include detailed information of emissions for each source category.

Short summary
To evaluate the quality of the satellite-derived NOx emissions, we compare nine emission inventories of nitrogen oxides including four satellite-derived NOx inventories and bottom-up inventories for East Asia. The temporal and spatial distribution of NOx emissions over East Asia are evaluated. We analyse the differences in satellite-derived emissions from two different inversion methods. The paper ends with recommendations for future improvements of emission estimates.
Final-revised paper