Black carbon (BC) aerosols influence precipitation through a range of processes. The climate response to the presence of BC is however highly dependent on its vertical distribution. Here, we analyze the changes in the energy budget and precipitation impacts of adding a layer of BC at a range of altitudes in two independent global climate models. The models are run with atmosphere‐only and slab ocean model setup to analyze both fast and slow responses, respectively. Globally, precipitation changes are tightly coupled to the energy budget. We decompose the precipitation change into contributions from absorption of solar radiation, atmospheric longwave radiative cooling, and sensible heat flux at the surface. We find that for atmosphere‐only simulations, BC rapidly suppresses precipitation, independent of altitude, mainly because of strong atmospheric absorption. This reduction is offset by increased atmospheric radiative longwave cooling and reduced sensible heat flux at the surface, but not of sufficient magnitude to prevent reduced precipitation. On longer timescales, when the surface temperature is allowed to respond, we find that the precipitation increase associated with surface warming can compensate for the initial reduction, particularly for BC in the lower atmosphere. Even though the underlying processes are strikingly similar in the two models, the resulting change in precipitation and temperature by BC differ quite substantially.

中文翻译：

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炭黑与降水：一种能量学观点

炭黑（BC）气溶胶会通过一系列过程影响降水。但是，对不列颠哥伦比亚省的气候响应高度依赖于其垂直分布。在这里，我们分析了在两个独立的全球气候模型中，在一定高度范围内添加一层BC的能源预算和降水影响的变化。这些模型在仅大气和平板海洋模型设置下运行，以分别分析快速和慢速响应。在全球范围内，降水变化与能源预算紧密相关。我们将降水变化分解为来自太阳辐射吸收，大气长波辐射冷却和表面显热通量的贡献。我们发现，对于仅用于大气的模拟，BC会迅速抑制降水，而与海拔高度无关，主要是因为强烈的大气吸收。这种减少被增加的大气辐射长波冷却和减少的表面显热通量抵消，但幅度不足以防止降水减少。在更长的时间尺度上，当允许表面温度响应时，我们发现与表面变暖相关的降水增加可以补偿初始减少，尤其是在较低大气层中的卑诗省。尽管两个模型的基本过程非常相似，但由BC引起的降水和温度变化却相差很大。在较长的时间尺度上，当允许表面温度响应时，我们发现与表面变暖相关的降水增加可以补偿初始减少，尤其是在较低大气层中的BC。尽管两个模型的基本过程非常相似，但由BC引起的降水和温度变化却相差很大。在较长的时间尺度上，当允许表面温度响应时，我们发现与表面变暖相关的降水增加可以补偿初始减少，尤其是在较低大气层中的BC。尽管两个模型的基本过程非常相似，但由BC引起的降水和温度变化却相差很大。