Huang Yeqi, Lu Xingcheng, Fung Jimmy C H, Wong David C, Li Zhenning, Chen Yiang, Chen Wanying
Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Department of Geography and Resource Management, The Chinese University of Hong Kong, Hong Kong, China.
Atmos Environ (1994). 2023 Feb 1;294. doi: 10.1016/j.atmosenv.2022.119521.
Southeast Asia (SEA) is one of the world's major sources of biomass burning (BB). In this study, the recently released Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) two-way coupled model was used with the Global Fire Emissions Database Version 4, to investigate the effect of BB emissions on the meteorology and air quality over SEA. The results show that the model performance was improved by considering BB emissions. When BB pollutants reach the free troposphere, they can be transported by westerly and southwesterly winds to downstream regions. The contributions of BB were up to 44.3 and 34.5 ppbv to surface O concentrations and 304.9 and 128.1 μg/m to surface PM concentrations in March and April, respectively. The BB emission caused aerosol direct radiative effect (DRE) on the monthly mean clear-sky downward shortwave flux decreased by -39.8 and -14.7 W/m in March and April, respectively. The surface temperature decreased over the land (by a maximum of -0.27 °C in March) and increased over the sea, while the temperature at higher levels tended to increase (to a maximum of 0.14 °C in March). The BB aerosol DRE caused the planetary boundary layer height (PBLH) to decrease by a maximum of -133.0 m in March. Surface O concentrations decreased generally owing to variations in the shortwave flux and temperature. Moreover, the decreased PBLH worsened the diffusion condition within the PBL but also caused larger amounts of BB emissions penetrating into the free atmosphere. This led to a decrease in surface PM concentrations in southern Indochina and Hainan Island and an increase in the rest of the regions. These findings highlight the key effects of BB emissions on local and downwind meteorology and air quality over SEA and demonstrate the practical applications of the WRF-CMAQ coupled model.
东南亚（SEA）是全球生物质燃烧（BB）的主要来源之一。在本研究中，使用最近发布的天气研究与预报-社区多尺度空气质量（WRF-CMAQ）双向耦合模型以及全球火灾排放数据库第4版，来研究生物质燃烧排放对东南亚地区气象和空气质量的影响。结果表明，考虑生物质燃烧排放后模型性能得到改善。当生物质燃烧污染物到达自由对流层时，它们可通过西风和西南风输送到下游地区。生物质燃烧对3月和4月地面O浓度的贡献分别高达44.3和34.5 ppbv，对地面PM浓度的贡献分别为304.9和128.1 μg/m。生物质燃烧排放导致气溶胶直接辐射效应（DRE）使3月和4月的月平均晴空向下短波通量分别减少-39.8和-14.7 W/m。陆地表面温度下降（3月最大降幅为-0.27°C），海洋表面温度上升，而较高层的温度趋于上升（3月最大升幅为0.14°C）。生物质燃烧气溶胶DRE导致行星边界层高度（PBLH）在3月最大下降-133.0 m。由于短波通量和温度的变化，地面O浓度总体下降。此外，PBLH的降低不仅恶化了行星边界层内的扩散条件，还导致大量生物质燃烧排放穿透到自由大气中。这导致印度支那南部和海南岛的地面PM浓度下降，其他地区则上升。这些发现突出了生物质燃烧排放在东南亚地区对当地和下风向气象及空气质量的关键影响，并展示了WRF-CMAQ耦合模型的实际应用。
