Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, PREMIC, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, PREMIC, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Sci Total Environ. 2021 Nov 10;794:148624. doi: 10.1016/j.scitotenv.2021.148624. Epub 2021 Jun 22.
Surface radiation is crucial to atmospheric boundary layer development and air pollution formation. Several studies have revealed that surface radiation plays a vital role in developing the daytime convective boundary layer that controls the explosive growth of PM concentration; however, less attention has been paid to the effects of changing nighttime surface radiation on the near-surface temperature inversion layer and PM accumulation. In this study, we used long-term observations of meteorological and environmental data and atmospheric boundary layer measurements during a severe PM pollution event to investigate the effect of changes in nocturnal surface radiation on the increase in PM concentrations. The results showed that surface radiation cooling was enhanced (weakened) by decreased (increased) cloud cover fraction by changing longwave radiation at night; this strengthened (weakened) near-surface temperature inversion intensity and promoted (prevented) the accumulated increase in PM. This observational study using 5-year data further confirmed the cloud radiative effect on the nighttime accumulation of PM with a significant negative correlation between nighttime averages of surface PM concentrations and cloud cover fractions. This reveals an important mechanism for the impact of surface radiation cooling modulated by cloud cover change on the nighttime accumulated increase in PM. This finding extends our understanding of air pollutant accumulation at night with potential implications for atmospheric environment change.
地表辐射对大气边界层发展和空气污染形成至关重要。多项研究表明，地表辐射在发展控制 PM 浓度爆炸式增长的日间对流边界层方面起着至关重要的作用；然而，人们对夜间地表辐射变化对近地表温度逆温层和 PM 积累的影响关注较少。在本研究中，我们利用气象和环境数据的长期观测以及在一次严重 PM 污染事件期间的大气边界层测量，研究了夜间地表辐射变化对 PM 浓度增加的影响。结果表明，通过改变夜间长波辐射，云覆盖率的降低（增加）增强（减弱）了地表辐射冷却；这加强（减弱）了近地表温度逆温强度，并促进（阻止）了 PM 的累积增加。这项使用 5 年数据的观测研究进一步证实了云辐射对夜间 PM 积累的影响，地表 PM 浓度和云覆盖率的夜间平均值之间存在显著的负相关关系。这揭示了地表辐射冷却受云量变化调节对夜间 PM 累积增加的影响的重要机制。这一发现扩展了我们对夜间大气污染物积累的理解，对大气环境变化具有潜在影响。
