Here, we present modeling evidence of the influences of aerosol feedback on secondary circulations (SCs). The results show that in heavily PM_2.5 polluted Beijing-Tianjin-Hebei (BTH) areas, the aerosol feedback is the primary factor on the occurrence and development of mesoscale SCs in the atmospheric boundary layer. Modeling evidence reveal that the impact of aerosol feedback on SCs is proportional to PM_2.5 concentrations or precursor emissions. During the 2014 Asia-Pacific Economic Cooperation (APEC) with extraordinary emission reduction, the time levels of SCs significantly decreases to ~37.3% of the periods without emission reduction before and after APEC period. The simulated PM_2.5 during APEC are ~47.6% of before and after APEC period, and the measured concentration ratio at 47.7%. The largest variation in SC occurred during the afternoon, which should be related to the stronger solar radiation. We found that the reduction in wind speed caused by aerosol feedback and related convergence and divergence of the air mass play a pivotal role in SCs evolution. Against the background of prevailing westerly winds in BTH, the strengthening and appearance of clockwise SCs caused by aerosol feedback leads to an increase in the frequency of surface easterly U-wind. These phenomena have also been validated in two other emission reduction events and the emission reduction actions in the BTH region in January and July of 2014, 2017, and 2020, respectively. The results of this paper showing substantial impact of aerosol feedback on SCs, which could help promote our understanding of content and level of aerosol feedback to atmospheric changes.

在这里，我们提供了气溶胶反馈对次级环流 （SCs） 影响的建模证据。结果表明：在_PM2.5重度污染的京津冀（BTH）地区，气溶胶反馈是影响大气边界层中尺度SCs发生和发展的主要因素。建模证据表明，气溶胶反馈对 SC 的影响与 PM_2.5 浓度或前体排放成正比。在 2014 年亚太经济合作组织 （APEC） 特别减排期间，SCs 的时间水平显著减少到 APEC 前后未减排时期的 ~37.3%。APEC 期间模拟的 PM_2.5 为 APEC 前后的 ~47.6%，实测浓度比为 47.7%。SC 的最大变化发生在下午，这应该与较强的太阳辐射有关。我们发现，气溶胶反馈引起的风速降低以及相关的气团收敛和发散在 SCs 演化中起着关键作用。在 BTH 盛行西风的背景下，气溶胶反馈引起的顺时针 SCs 的增强和出现导致地面偏东 U 风的频率增加。这些现象也分别在 2014 年 1 月和 2014 年 1 月和 7 月的 BTH 地区其他两次减排事件和减排行动中得到验证。本文的结果表明气溶胶反馈对 SC 有重大影响，这可能有助于促进我们对气溶胶对大气变化的反馈内容和水平的理解。