Distinct surface response to black carbon aerosols
Distinct surface response to black carbon aerosols
复制标题
对黑碳气溶胶的明显表面响应
DOI：
10.5194/acp-21-13797-2021
复制
发表时间：
2021-05
影响因子：
6.3
通讯作者：
T. Tang;D. Shindell;Yuqiang Zhang;A. Voulgarakis;J. Lamarque;G. Myhre;G. Faluvegi;B. Samset;T. Andrews;D. Oliviè;T. Takemura;X. Lee
中科院分区：
文献类型：
--
作者：
T. Tang;D. Shindell;Yuqiang Zhang;A. Voulgarakis;J. Lamarque;G. Myhre;G. Faluvegi;B. Samset;T. Andrews;D. Oliviè;T. Takemura;X. Lee
抽象的。对于单个气候强迫的辐射影响，以往的研究主要集中在大气层顶的全球平均值（TOA），而对地面过程，尤其是黑碳气溶胶的辐射影响关注较少。在这项研究中，地面辐射响应五个不同的强迫剂进行了分析，通过使用理想化模式模拟。分析表明，对于温室气体、太阳辐射和散射气溶胶，地表温度的变化主要取决于地表辐射加热的变化，而对于BC，不同组分之间的地表能量再分配起着更重要的作用。在全球范围内，当在TOA施加单位BC强迫时，地面的净短波辐射减少了5.09 ± 1.80 W m−2（全球陆地平均值），这部分被来自温暖大气的向下长波辐射增加（1.67 ± 0.24 W m−2）所抵消，导致向下入射的地面辐射净减少3.42 ± 0.51 W m−2。尽管向下辐射能量减少，但由于能量耗散效率降低，地表空气温度仍然增加了0.14 ± 0.05 K，表现为地表感热通量（2.53 ± 0.37 W m−2）和潜热通量（1.30 ± 0.27 W m−2）减少，以及波文比（0.18 ± 0.05）减少。湍流通量的减少主要是由于大气稳定度的增加（0.06 ± 0.01 K）和地面风速的降低（0.05 ± 0.01 m s−1）。增强的稳定性是由于更快的大气变暖相对于表面，而风速降低可以部分地解释增强的稳定性和减少赤道到极点的大气温度梯度。BC强迫下的这些快速调整对地表能量再分配产生了“自上而下”的影响，因此，地表温度响应，这是在温室气体或散射气溶胶下观察不到的。我们的研究为吸收气溶胶对表面能量平衡和表面温度响应的影响提供了新的见解。
Abstract. For the radiative impact of individual climate forcings, most previous studies focused on the global mean values at the top of the atmosphere (TOA) and less attention has been paid to surface processes, especially for black carbon aerosols. In this study, the surface radiative responses to five different forcing agents were analyzed by using idealized model simulations. Our analyses reveal that for greenhouse gases, solar irradiance and scattering aerosols, the surface temperature changes are mainly dictated by the changes of surface radiative heating, but for BC, surface energy redistribution between different components plays a more crucial role. Globally, when a unit BC forcing was imposed at TOA, the net shortwave radiation at the surface decreased by 5.09 ± 1.80 W m−2 (averaged over global land), which is partially offset by increased downward longwave radiation (1.67 ± 0.24 W m−2) from the warmer atmosphere, causing a net decrease in the incoming downward surface radiation of 3.42 ± 0.51 W m−2. Despite a reduction in the downward radiation energy, the surface air temperature still increased by 0.14 ± 0.05 K because of less efficient energy dissipation, manifested by reduced surface sensible (2.53 ± 0.37 W m−2) and latent heat flux (1.30 ± 0.27 W m−2), as well as a decrease of Bowen ratio (0.18 ± 0.05). Such reductions of turbulent fluxes can be largely explained by enhanced air stability (0.06 ± 0.01 K), measured as the difference of the potential temperature between 925 hPa and surface, and reduced surface wind speed (0.05 ± 0.01 m s−1). The enhanced stability is due to the faster atmospheric warming relative to the surface whereas the reduced wind speed can be partially explained by enhanced stability and reduced equator-to-pole atmospheric temperature gradient. These rapid adjustments under BC forcing exerted a “top-down” impact on the surface energy redistribution and thus, surface temperature response, which is not observed under greenhouse gas or scattering aerosols. Our study provides new insights into the impact of absorbing aerosols on surface energy balance and surface temperature response.