Model Analysis of Influences of Aerosol Mixing State upon Its Optical Properties in East Asia

The air quality model system RAMS （Regional Atmospheric Modeling System）-CMAQ （Models-3 Com- munity Multi-scale Air Quality） coupled with an aerosol optical/radiative module was applied to investigate the impact of different aerosol mixing states （i.e., externally mixed, half externally and half internally mixed, and internally mixed） oil radiative forcing in East Asia. The simulation results show that the aerosol optical depth （AOD） generally increased when the aerosol mixing state changed from externally mixed to internally mixed, while the single scattering albedo （SSA） decreased. Therefore, the scattering and absorption proper- ties of aerosols can be significantly affected by the change of aerosol mixing states. Comparison of simulated and observed SSAs at five AERONET （Aerosol Robotic Network） sites suggests that SSA could be better estimated by considering aerosol particles to be internally mixed. Model analysis indicates that the impact of aerosol mixing state upon aerosol direct radiative forcing （DRF） is complex. Generally, the cooling effect of aerosols over East Asia are enhanced in the northern part of East Asia （Northern China, Korean peninsula, and the surrounding area of Japan） and are reduced in the southern part of East. Asia （Sichuan Basin and Southeast China） by internal mixing process, and the variation range can reach ＋5 W m 2. The analysis shows that the internal mixing between inorganic salt and dust is likely the main reason that the cooling effect strengthens. Conversely, the internal nfixture of anthropogenic aerosols, including sulfate, nitrate, ammonium, black carbon, and organic carbon, could obviously weaken the cooling effect.

Particulate matter trends and quantification of the spring sand-dust contribution in Hohhot,Inner Mongolia,from 2013 to 2017

2013年9月国务院颁布了《大气污染防治行动计划》.研究其实施前后呼和浩特市大气污染物浓度变化及及原因;同时,分析了春季沙尘天气对于呼和浩特市大气环境颗粒物浓度的定量影响.结果表明:呼和浩特市大气环境质量持续改善,但大气污染物浓度仍然较高.PM_(2.5)和PM10年均浓度分别超过国家二级标准22.9%和35.7%;2013-2017年春季PM_(2.5)和PM10浓度降幅较大,沙尘天气对呼和浩特市PM_(2.5),PM10,和TSP浓度的绝对贡献范围分别在0.6-5.2μg m^(-3),9.0-16.9μg m^(-3)和14.7-30.0μg m^(-3).

太原大气二氧化碳浓度变化及传输特征分析

本文首次使用太原温室气体观测站2016–2018年大气CO2,PM2.5,PM1.0浓度等观测数据,分析了城市地区大气CO2浓度的月,日分布特征,周末效应,霾日与非霾日变化特征。分析表明,太原地区CO2浓度秋,冬季高于春,夏季;霾日高于非霾日;四季日变化特征均呈‘单峰单谷’型;工作日整体略高于非工作日,特别是早高峰浓度差明显。利用HYSPLIT后向轨迹模式分析得出,太原CO2浓度主要受局地源汇影响,水平扩散可降低其浓度,而小风天气则不利于CO2扩散。高空风向,风速与近地面有区别,SW-W-NW扇区近距离气团对太原四季CO2浓度抬升明显,太原区域CO2以本地贡献为主。