Effects of aerosol-radiation feedback and topography during an air pollution event over the North China Plain during December 2017
Effects of aerosol-radiation feedback and topography during an air pollution event over the North China Plain during December 2017
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DOI：
10.1016/j.apr.2018.10.006
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发表时间：
2019-03
影响因子：
4.5
通讯作者：
Dongdong Wang;Baolin Jiang;Wenshi Lin;Feng-feng Gu
中科院分区：
文献类型：
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作者：
Dongdong Wang;Baolin Jiang;Wenshi Lin;Feng-feng Gu
在线耦合天气研究和预报化学 (WRF-Chem) 模型用于调查 2017 年 12 月 27 日至 30 日在华北平原 (NCP) 发生的区域性霾事件。对行星边界层 (PBL) 内有和没有气溶胶辐射反馈的建模场景进行了调查。通过在模型中添加气溶胶辐射反馈，我们捕获了该事件期间观测到的温度和相对湿度 (RH) 以及地表 PM2.5、SO2 和 NO2 浓度的空间和时间特征。此次事件的主要气象驱动因素是稳定的气象条件，即低PBL、强逆温、高相对湿度和弱风场。气溶胶辐射反馈机制影响了这些气象场，导致最大地表太阳辐射、地表能量收支、PBL高度、地表2米温度和中层大气相对湿度减少，同时地表2米相对湿度、中层大气温度和大气稳定性增加。气象变量的变化反过来影响了空气污染物的分布和浓度，此次事件期间NCP上空PM2.5增加了20μg/m3以上。另在太行山和燕山山区进行了敏感性实验，将地形平坦化至30米高，以探讨地形对华北地区空气污染的影响。模型揭示了与这两座山相关的各种地形对气象变量的影响，包括降低的 PBL 高度、降低的风速、阻挡均匀的地面风以及更强烈的逆温。因此，在本次实验中，NCP 上空的地表空气污染物浓度增加不均匀。在 WRF-Chem 模型中实施更详细的 PBL 流程以及无线电探空仪和卫星数据产品将改善对 NCP 雾霾形成的模拟。
The online coupled Weather Research and Forecasting-Chemistry (WRF-Chem) model was used to investigate a regional haze event, which occurred over the North China Plain (NCP) from 27 to 30 December 2017. Modeling scenarios with and without aerosol-radiation feedback within the planetary boundary layer (PBL) were investigated. By adding aerosol-radiation feedback to the model, we captured the spatial and temporal characteristics of the observed temperature and relative humidity (RH), as well as surface PM2.5, SO2, and NO2concentrations during this event. The primary meteorological driver of this event was stable meteorological conditions, namely, a low PBL, strong temperature inversion, high RH, and a weak wind field. Aerosol-radiation feedback mechanisms affected these meteorological fields, causing reductions in maximum surface solar radiation, the surface energy budget, PBL height, surface 2-m temperature and middle atmosphere RH, while increasing surface 2-m RH, middle atmosphere temperature, and atmospheric stability. Changes in meteorological variables in turn affected air pollutant distributions and concentrations, with PM2.5increasing by more than 20 μg/m3over the NCP during this event. Another sensitivity experiment was carried out over the Taihang and Yanshan mountain areas, in which topography was flattened to a 30-m height to explore the impacts of topography on air pollution in the NCP region. Modeling revealed various topographic effects on meteorological variables related to these two mountains, including a lowered PBL height, reduced wind speed, blocked uniform surface winds, and more intense temperature inversion. Consequently, surface air pollutant concentrations increased unevenly over the NCP in this experiment. Implementation of more detailed PBL processes, as well as radiosonde and satellite data products into the WRF-Chem model would improve simulations of haze formation over the NCP.