Print Email Facebook Twitter Evaluation of modeling NO2 concentrations driven by satellite-derived and bottom-up emission inventories using in situ measurements over China Title Evaluation of modeling NO2 concentrations driven by satellite-derived and bottom-up emission inventories using in situ measurements over China Author Liu, Fei (Royal Netherlands Meteorological Institute (KNMI); Universities Space Research Association; NASA Goddard Space Flight Center) van der A, Ronald J. (Royal Netherlands Meteorological Institute (KNMI)) Eskes, Henk (Royal Netherlands Meteorological Institute (KNMI)) Ding, J. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)) Mijling, Bas (Royal Netherlands Meteorological Institute (KNMI)) Date 2018-03-27 Abstract Chemical transport models together with emission inventories are widely used to simulate NO2 concentrations over China, but validation of the simulations with in situ measurements has been extremely limited. Here we use ground measurements obtained from the air quality monitoring network recently developed by the Ministry of Environmental Protection of China to validate modeling surface NO2 concentrations from the CHIMERE regional chemical transport model driven by the satellite-derived DECSO and the bottom-up MIX emission inventories. We applied a correction factor to the observations to account for the interferences of other oxidized nitrogen compounds (NOz), based on the modeled ratio of NO2 to NOz. The model accurately reproduces the spatial variability in NO2 from in situ measurements, with a spatial correlation coefficient of over 0.7 for simulations based on both inventories. A negative and positive bias is found for the simulation with the DECSO (slope= 0.74 and 0.64 for the daily mean and daytime only) and the MIX (slope= 1.3 and 1.1) inventories, respectively, suggesting an underestimation and overestimation of NOx emissions from corresponding inventories. The bias between observed and modeled concentrations is reduced, with the slope dropping from 1.3 to 1.0 when the spatial distribution of NOx emissions in the DECSO inventory is applied as the spatial proxy for the MIX inventory, which suggests an improvement of the distribution of emissions between urban and suburban or rural areas in the DECSO inventory compared to that used in the bottom-up inventory. A rough estimate indicates that the observed concentrations, from sites predominantly placed in the populated urban areas, may be 10-40 % higher than the corresponding model grid cell mean. This reduces the estimate of the negative bias of the DECSO-based simulation to the range of -30 to 0 % on average and more firmly establishes that the MIX inventory is biased high over major cities. The performance of the model is comparable over seasons, with a slightly worse spatial correlation in summer due to the difficulties in resolving the more active NOx photochemistry and larger concentration gradients in summer by the model. In addition, the model well captures the daytime diurnal cycle but shows more significant disagreement between simulations and measurements during nighttime, which likely produces a positive model bias of about 15 % in the daily mean concentrations. This is most likely related to the uncertainty in vertical mixing in the model at night. To reference this document use: http://resolver.tudelft.nl/uuid:15dd135b-378f-4fd5-9ee7-a7a3145833bc DOI https://doi.org/10.5194/acp-18-4171-2018 ISSN 1680-7316 Source Atmospheric Chemistry and Physics (online), 18 (6), 4171-4186 Part of collection Institutional Repository Document type journal article Rights © 2018 Fei Liu, Ronald J. van der A, Henk Eskes, J. Ding, Bas Mijling Files PDF acp_18_4171_2018.pdf 5.88 MB Close viewer /islandora/object/uuid:15dd135b-378f-4fd5-9ee7-a7a3145833bc/datastream/OBJ/view