Center for International Climate and Environmental Research-Oslo (CICERO), P.O. Box 1129 Blindern, N-0318 Oslo, Norway.
Nat Commun. 2014 Sep 25;5:5065. doi: 10.1038/ncomms6065.
Black carbon (BC), unlike most aerosol types, absorbs solar radiation. However, the quantification of its climate impact is uncertain and presently under debate. Recently, attention has been drawn both to a likely underestimation of global BC emissions in climate models, and an overestimation of BC at high altitudes. Here we show that doubling present day BC emissions in a model simulation, while reducing BC lifetime based on observational evidence, leaves the direct aerosol effect of BC virtually unchanged. Increased emissions, together with increased wet removal that reduces the lifetime, yields modelled BC vertical profiles that are in strongly improved agreement with recent aircraft observations. Furthermore, we explore the consequences of an altered BC profile in a global circulation model, and show that both the vertical profile of BC and rapid climate adjustments need to be taken into account in order to assess the total climate impact of BC.
黑碳（BC）与大多数气溶胶类型不同，它会吸收太阳辐射。然而，其气候影响的量化仍然不确定，目前还存在争议。最近，人们不仅关注到气候模型中对全球 BC 排放量的低估，也关注到对高海拔地区 BC 的高估。在这里，我们表明，在模型模拟中，将目前的 BC 排放量增加一倍，同时根据观测证据减少 BC 的寿命，BC 的直接气溶胶效应几乎保持不变。增加排放量，再加上增加的湿清除，减少了寿命，使得模型模拟的 BC 垂直分布与最近的飞机观测结果更为一致。此外，我们还探讨了在全球环流模型中改变 BC 分布的后果，并表明为了评估 BC 的总气候影响，需要考虑 BC 的垂直分布和快速的气候调整。
