This study evaluated the impact of the aerosol direct effect (ADE) on the meteorological conditions and air quality in Seoul, South Korea (Korea), using the WRF-CMAQ coupled model. Two experiments were conducted: NF simulation without the ADE feedback and YF simulation with the ADE feedback. The ADE resulted in a decrease in shortwave radiation at the surface and an increase in shortwave radiation in the atmosphere. Additionally, the 2-m temperature, 10-m wind speed, and planetary boundary layer (PBL) height decreased. The changes in meteorological conditions due to ADE-induced atmospheric stability and restrained vertical mixing resulted in deteriorated air quality. During the simulation, PM_2.5 concentrations increased due to ADE, with daily averages rising by 4.2 µg·m⁻³ on transport day and 3.2 µg·m⁻³ on accumulation day. Process analysis (PA) was employed to investigate contributions of physical/chemical processes affecting ADE. Local emissions, aerosol processes, and horizontal advection were identified as key factors in PM_2.5 increases in Seoul. Differences in the contributions of processes were noted between transport and accumulation day due to ADE considerations. On transport day, the YF simulation exhibited a higher influx of PM_2.5 through horizontal advection, attributed to transport from upwind regions. Conversely, on accumulation day, horizontal advection decreased due to enhanced atmospheric stability, while vertical transport increased from restrained vertical mixing induced by ADE. Thus, ADE emphasized the contribution of processes to PM_2.5. Emissions and horizontal advection were primary contributors on transport day, while the emissions process dominated on accumulation day.

本研究使用 WRF-CMAQ 耦合模型评估了气溶胶直接效应 (ADE) 对韩国首尔气象条件和空气质量的影响。进行了两个实验：没有 ADE 反馈的 NF 模拟和有 ADE 反馈的 YF 模拟。ADE 导致地表短波辐射减少，大气中短波辐射增加。此外，2 米温度、10 米风速和行星边界层 (PBL) 高度均下降。ADE引起的大气稳定性和垂直混合受限导致气象条件发生变化，导致空气质量恶化。模拟过程中，由于ADE的影响， PM _2.5浓度有所增加，运输日日均浓度上升4.2 µg·m ^-3 ，积聚日日均浓度上升3.2 µg·m ^{-3 。}采用过程分析 (PA) 来研究影响 ADE 的物理/化学过程的贡献。当地排放、气溶胶过程和水平平流被确定为首尔PM _{2.5增加的关键因素。}出于 ADE 的考虑，运输日和积累日之间的过程贡献存在差异。_{在运输日，YF 模拟显示通过水平平流流入的 PM 2.5}较高，这归因于来自逆风区域的运输。相反，在积聚日，由于大气稳定性增强，水平平流减少，而由于 ADE 引起的垂直混合受限，垂直输送增加。_{因此，ADE强调了流程对PM 2.5}的贡献。排放和水平平流是运输日的主要贡献者，而排放过程在累积日占主导地位。