There is consensus among climate models that Arctic climate is particularly sensitive to anthropogenic greenhouse gases and that, over the next century, Arctic surface temperatures are projected to rise at a rate about twice the global mean. The response of Arctic surface temperatures to greenhouse gas thermal emission is modified by Northern Hemisphere synoptic meteorology and local radiative processes. Aerosols may play a contributing factor through changes to cloud radiative properties. Here we evaluate a previously suggested contribution of anthropogenic aerosols to cloud emission and surface temperatures in the Arctic. Using four years of ground-based aerosol and radiation measurements obtained near Barrow, Alaska, we show that, where thin water clouds and pollution are coincident, there is an increase in cloud longwave emissivity resulting from elevated haze levels. This results in an estimated surface warming under cloudy skies of between 3.3 and 5.2 W m~(-2) or 1 and 1.6℃. Arctic climate is closely tied to cloud longwave emission, but feedback mechanisms in the system are complex and the actual climate response to the described sensitivity remains to be evaluated.
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机译：在气候模型之间达成共识，即北极气候对人为温室气体特别敏感，并且在下一世纪，预计北极地表温度将以全球平均值的两倍速度上升。北半球的天气学和局部辐射过程改变了北极表面温度对温室气体热辐射的响应。气溶胶可能通过改变云的辐射特性而发挥作用。在这里，我们评估了先前建议的人为气溶胶对北极云排放和地表温度的贡献。使用在阿拉斯加巴罗附近获得的四年地面气溶胶和辐射测量结果，我们发现，在薄水云和污染同时发生的地方，由于雾霾水平升高，云长波发射率增加。这导致在多云的天空下，估计的地面变暖为3.3至5.2 W m〜（-2）或1至1.6℃。北极气候与云长波辐射密切相关，但是系统中的反馈机制很复杂，对描述的敏感性的实际气候响应仍有待评估。
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