高效率颗粒物微物理模型简介与重污染过程应用分析

中国细颗粒物(PM2.5)导致的空气污染和雾霾天气问题越来越突出,在低层对流层中很多地方都有显著的二次颗粒物生成过程,因此对颗粒物物理化学转化过程的研究具有重要意义,其转化过程对空气质量模式模拟和预报的准确性有重要影响。高效率颗粒物微物理(APM)模型经过近20多年的研究和发展,在全球化学传输模型(GEOS-Chem)、区域性气象和化学预报模型(WRF-Chem)通用地球系统模型(CESM-CAM5)等气象及环境空气质量预报模型中取得了很好的应用验证,能够在全球/区域等不同尺度对粒子生成、长大、凝聚、消除等微物理过程以及气溶胶光学厚度(AOD)、直接/间接辐射强迫等进行模拟。应用GEOS-Chem-APM模式模拟了2014年2月京津冀区域的重污染过程。结果显示,湿度模拟的准确性对其他物理和污染物浓度等模拟结果有重要作用;2月20—26日的重污染过程模拟结果与实际观测较为吻合,主要污染特点是较高的湿度(90%以上),同时,二次颗粒物和包裹了二次物种的一次颗粒物(黑碳/有机碳)是低能见度的最大贡献者。

Advanced Aerosol Microphysics Model and Application in Heavy Air Pollution in China

Haze and air pollution problems caused by PM_2.5 play an important role in China. In many places of the lower troposphere, there is significant formation process of secondary particles. Therefore, the research on the physical and chemical conversion process of particles is of great significance, which has an important influence on the air quality model simulation and the accuracy of forecasting. High efficiency particulate microphysics (APM) model had been incorporated into the global chemical transport model (GEOS-Chem), regional meteorological and chemical prediction model (WRF-Chem) and the community earth system model (CESM-CAM5) to simulate global/regional different scale on the particle generation, grew up, condensation, elimination of microphysical processes, aerosol optical thickness (AOD), direct/indirect radiative forcing. The GEOS-Chem-APM model is used in this study to simulate the heavy pollution process in the Beijing Tianjin Hebei region in February 2014. The results revealed that the accuracy of humidity simulation plays an important role for other physical process and pollutant concentration simulation, and the simulation results in this study are in good agreement with the actual observations for the heavy pollution process from February 20 to 26. The main characteristics of pollution is high humidity (more than 90%), and secondary particles and primary particle coated with secondary species (black carbon/organic carbon) is the biggest contribution to the low visibility.