MICS-Asia II: An inter-comparison study of emission inventories for the Japan region

For the model intercomparison study, MICS Asia phase II, standard air pollutants emission data are provided from published research results (the TRACE-P data set) and other recent work. To provide preliminary information concerning the reliability of the standard emissions data, this inventory was compared with a local emission inventory, EAGrid2000-Japan, which has been developed for detailed analyses with fine grid data resolution for the Japan region. Although these inventories are based upon different estimation methodologies, from the comparative analyses it was found that regional emissions of the standard data are consistent, with differences smaller than 10% for SO2, NOx, NMVOC and CO2, and smaller than 30% for CO and NH3. Differences for all species are smaller than the 95% confidence intervals that were estimated in the research that produced the standard emissions data. Additional information is provided regarding emissions of PM10 and PM2.5, although these did not originate in the TRACE-P data. Furthermore, it was found that the 0.5°×0.5° grid-based emissions from the two inventories match well for NOx, NMVOC, CO, and PM2.5, even though the spatial allocation techniques for the local inventory are much more detailed. For SO2 emissions, the differences in the grid-based inventories are greater. Although some problems still remain, such as diurnal variations that are not considered in the standard emissions data, the intercomparison analysis suggests that the standard emissions data have appropriate properties for atmospheric model simulation.