Simulation and Validation of the Aerosol Optical Thicknessover China in 2006

The Model of Atmospheric Transport and Chemistry (MATCH) developed by the US National Center for Atmospheric Research (NCAR) was used to calculate the aerosol optical thickness (AOT) over China in 2006, with emission source data of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) and NCEP/NCAR reanalysis data as inputs. The simulation results of AOT were then validated with observational data from the Moderate Resolution Imaging Spectroradiometer (MODIS), Chinese Sun Hazemeter Network (CSHNET), Aerosol Robotics Network (AERONET), and China Aerosol Remote Sensing Network (CARSNET) at more than 30 stations over China. The comparison results indicated that the high values of AOT in the areas such as the Sichuan basin and East and South China and the low values of AOT over the Tibetan Plateau and Northwest and Northeast China were reasonably simulated by the MATCH. This model tended to underestimate the AOT values in high-aerosol-loading areas but overestimate the AOT values in less polluted areas because there are still large uncertainties in the expression of emission sources, the description of the optical properties of aerosols, the treatment of cloud and precipitation, and the selection of grid resolution. The modeling results were consistent with the CSHNET, CARSNET, AERONET, and MODIS data in most parts of China, and the correlation coefficient of the monthly mean AOT between the model and the observation was 0.79 with CSHNET data at 23 stations, 0.51 with MODIS data, and 0.88 with data at 3 CARSNET stations and 2 other stations. All of them passed the significance test with α < 0.0001. The results demonstrated that the MATCH has the ability to simulate the characteristics of the AOT distribution and its seasonal variation over China.