Substantial Uncertainties in Arctic Aerosol Simulations by Microphysical Processes Within the Global Climate‐Aerosol Model CAM‐ATRAS
Substantial Uncertainties in Arctic Aerosol Simulations by Microphysical Processes Within the Global Climate‐Aerosol Model CAM‐ATRAS
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DOI：
10.1029/2022jd036943
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
H. Matsui;Mingxu Liu
中科院分区：
文献类型：
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作者：
H. Matsui;Mingxu Liu
气溶胶可以通过与辐射、云以及冰雪表面的相互作用来调节北极气候。北极气溶胶的大气模拟仍然高度不确定，气溶胶微物理特性和过程的重要性尚未得到适当评估。为了确定这种巨大不确定性的原因，我们通过使用全球气候气溶胶模型社区大气模型以及用于形成和老化模拟的气溶胶二维箱模块，评估了由于各种气溶胶微物理特性/过程的不确定性而导致的北极气溶胶的变异范围，这些气溶胶微物理特性/过程包括排放时的粒径分布、颗粒混合状态、活化效率和除湿过程。我们发现，与这些多种微物理特性/过程相关的综合不确定性导致北极气溶胶的浓度和辐射效应存在 10-50 倍的差异（最大与最小比率）。黑碳在气溶胶种类中表现出最高的变异性，因为其较低的吸湿性和较高的临界过饱和度导致运输过程中的活化和除湿分数对气溶胶和云微物理的模型处理高度敏感。在北极，大气层顶部的气溶胶-辐射-云相互作用从-0.40到+0.30 W m−2变化（从工业化前到现在），并且可以是正值或负值，具体取决于微物理特性/过程的处理。这些结果表明，在北极气溶胶模拟中，微物理特性/过程比以前认为的更重要，并表明需要更好地理解气溶胶微物理特性/过程并进行更复杂的模型表示，以提高北极气溶胶模拟及其对气候影响的准确性。
Aerosols can modulate the Arctic climate through their interactions with radiation, clouds, and snow and ice surfaces. Atmospheric simulations of Arctic aerosols remain highly uncertain, for which the importance of aerosol microphysical properties and processes has not been properly evaluated. To identify the cause of this large uncertainty, we evaluate the variability ranges of aerosols in the Arctic resulting from uncertainties in various aerosol microphysical properties/processes, including particle size distributions at emission, particle mixing states, activation efficiency, and wet removal processes, by using a global climate‐aerosol model Community Atmosphere Model with the Aerosol Two‐dimensional bin module for foRmation and Aging Simulation. We find that the combined uncertainties associated with these multiple microphysical properties/processes yield a factor of 10–50 differences (maximum‐to‐minimum ratio) in the concentrations and radiative effects of aerosols in the Arctic. Black carbon shows the highest variability among aerosol species because its lower hygroscopicity and higher critical supersaturation cause the fraction of activation and wet removal during transport to be highly sensitive to the model treatment of aerosol and cloud microphysics. Aerosol‐radiation‐cloud interactions at the top of atmosphere vary from −0.40 to +0.30 W m−2 in the Arctic (from the preindustrial to present day) and can be positive or negative depending on the treatment of microphysical properties/processes. These results indicate that microphysical properties/processes are more important than previously thought in aerosol simulations in the Arctic and demonstrate that a better understanding and more sophisticated model representation of aerosol microphysical properties/processes are required to improve the accuracy of Arctic aerosol simulations and their impacts on climate.