Mechanism of Fast Atmospheric Energetic Equilibration Following Radiative Forcing by CO 2
Mechanism of Fast Atmospheric Energetic Equilibration Following Radiative Forcing by CO 2
复制标题
CO 2 辐射强迫后的快速大气能量平衡机制
DOI：
10.1002/2017ms001116
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发表时间：
2017
影响因子：
6.8
通讯作者：
Fueglistaler, S.
中科院分区：
文献类型：
--
作者：
Dinh, T.;Fueglistaler, S.
在能量平衡中，大气的净辐射发散（）由感热通量（）和潜热通量（）平衡，即， . CO2增加的辐射强迫减少，CO2增加后的地表变暖主要是由于大气能量需求的减少， 并且只有较小的表面辐射收支扰动。利用理想化的大气环流模式，我们证明了在地面温度固定的情况下，快速的大气调整产生了所需的 和 通过近地表温度和比湿度的变化。在靠近地表的层中，减少的辐射冷却迫使温度升高，导致负普朗克辐射反馈，并且由于减少的地表-大气温差，也导致显热通量减少。在自由对流层中，辐射冷却的减少导致对流层环流的减弱。因此，从近地表各层输出的水通量减少，降水量也减少。通过质量守恒，近地表比湿增加，表面蒸发减少，直到平衡减少的输出通量。其他过程可以放大或抑制反应， 和 并改变这两个通量之间的分配，但它们本身并不保证。
In energetic equilibrium, the atmosphere's net radiative divergence ( ) is balanced by sensible ( ) and latent ( ) heat fluxes, i.e., . Radiative forcing from increasing CO2reduces , and the surface warming following an increase in CO2is largely due to the reduction in atmospheric energy demand in and , with only a smaller surface radiative budget perturbation. With an idealized General Circulation Model, we show that the fast atmospheric adjustment at fixed surface temperature produces the required decrease in the sum of and through changes in the near‐surface temperature and specific humidity. In layers near the surface, the reduced radiative cooling forces a temperature increase that leads to a negative Planck radiative feedback and, because of the reduced surface‐atmosphere temperature difference, also to a reduction in sensible heat flux. In the free troposphere, the reduced radiative cooling leads to a weakening of the tropospheric circulation. Consequently, there is a decrease in the water flux exported from the layers near the surface, and as such in precipitation. By mass conservation, the near‐surface specific humidity increases and surface evaporation decreases until it balances the reduced export flux. Other processes can amplify or dampen the responses in and and change the partitioning between these two fluxes, but by themselves do not ensure .