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 (BC) 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 is imposed at TOA, the net shortwave radiation at the surface decreases by $-\mathrm{5.87}\pm \mathrm{0.67}$ W m⁻² (W m⁻²)⁻¹ (averaged over global land without Antarctica), which is partially offset by increased downward longwave radiation (2.32±0.38 W m⁻² (W m⁻²)⁻¹ from the warmer atmosphere, causing a net decrease in the incoming downward surface radiation of $-\mathrm{3.56}\pm \mathrm{0.60}$ W m⁻² (W m⁻²)⁻¹. Despite a reduction in the downward radiation energy, the surface air temperature still increases by 0.25±0.08 K because of less efficient energy dissipation, manifested by reduced surface sensible ($-\mathrm{2.88}\pm \mathrm{0.43}$ W m⁻² (W m⁻²)⁻¹) and latent heat flux ($-\mathrm{1.54}\pm \mathrm{0.27}$ W m⁻² (W m⁻²)⁻¹), as well as a decrease in Bowen ratio ($-\mathrm{0.20}\pm \mathrm{0.07}$ (W m⁻²)⁻¹). Such reductions of turbulent fluxes can be largely explained by enhanced air stability (0.07±0.02 K (W m⁻²)⁻¹), measured as the difference of the potential temperature between 925 hPa and surface, and reduced surface wind speed ($-\mathrm{0.05}\pm \mathrm{0.01}$ m s⁻¹ (W m⁻²)⁻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 occur in the lower atmosphere and propagate downward to influence the surface energy redistribution and thus surface temperature response, which is not observed under greenhouse gases or scattering aerosols. Our study provides new insights into the impact of absorbing aerosols on surface energy balance and surface temperature response.

中文翻译：

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对黑碳气溶胶的不同表面响应

对于个别气候强迫的辐射影响，以往的研究大多集中在大气顶部（TOA）的全球平均值，而较少关注地表过程，尤其是黑碳（BC）气溶胶。在这项研究中，通过使用理想化模型模拟分析了对五种不同强迫剂的表面辐射响应。我们的分析表明，对于温室气体、太阳辐照度和散射气溶胶，表面温度变化主要由表面辐射加热的变化决定，但对于 BC，不同组分之间的表面能重新分配起着更关键的作用。在全球范围内，当在 TOA 上施加一个单位的 BC 强迫时，地表的净短波辐射减少$——\mathrm{5.87}\pm \mathrm{0.67}$ W m ^-2  (W m ^-2 ) ^-1（除南极洲以外的全球陆地的平均值），部分被来自较暖大气的向下长波辐射 ( 2.32±0.38  W m ^-2  (W m ^-2 ) ^{-1 所}抵消），导致入射向下表面辐射的净减少$——\mathrm{3.56}\pm \mathrm{0.60}$ W m ^-2  (W m ^-2 ) ^-1。尽管向下辐射能量减少，但 由于能量耗散效率较低，地表空气温度仍增加了0.25±0.08 K，表现为表面感热（$——\mathrm{2.88}\pm \mathrm{0.43}$ W m ^-2  (W m ^-2 ) ^-1 ) 和潜热通量 ($——\mathrm{1.54}\pm \mathrm{0.27}$ W m ^-2  (W m ^-2 ) ^-1 )，以及鲍温比的降低 ($——\mathrm{0.20}\pm \mathrm{0.07}$ (W m ^-2 ) ^-1 )。湍流通量的这种减少可以在很大程度上解释为增强的空气稳定性 ( 0.07±0.02  K (W m ^-2 ) ^-1 )，测量为 925 hPa 和地表之间的潜在温度差，以及降低的地表风速 ($——\mathrm{0.05}\pm \mathrm{0.01}$ m s ^-1  (W m ^-2 ) ^-1 )。稳定性增强是由于相对于地表的大气变暖速度更快，而风速降低的部分原因是稳定性增强和赤道到极地大气温度梯度的降低。这些在 BC 强迫下的快速调整发生在低层大气中，并向下传播以影响表面能重新分布，从而影响表面温度响应，而这在温室气体或散射气溶胶下是观察不到的。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。