Constraining Aging Processes of Black Carbon in the Community Atmosphere Model Using Environmental Chamber Measurements
Constraining Aging Processes of Black Carbon in the Community Atmosphere Model Using Environmental Chamber Measurements
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DOI：
10.1029/2018ms001387
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发表时间：
2018-10
影响因子：
6.8
通讯作者：
Y. Wang;P. Ma;Jianfei Peng;Renyi Zhang;J. Jiang;R. Easter;Y. Yung
中科院分区：
文献类型：
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作者：
Y. Wang;P. Ma;Jianfei Peng;Renyi Zhang;J. Jiang;R. Easter;Y. Yung
黑碳气溶胶（BC）对地球系统的直接辐射强迫一直没有得到解决，这主要是由于BC在其整个生命周期中物理性质的不确定性。在这里，我们表明，环境室测量的BC属性提供了一个新的约束，在气候模型中的原油BC老化表示。当社区大气模型版本5中模态气溶胶模块（MAM4）气溶胶方案的四模式版本中的老化过程通过最近的原位室测量进行校准时，可以再现BC显著吸收增强的观测证据。在老化时间尺度计算中开发了一种基于观察的缩放方法，以减轻模拟模型化学成分中偏差的影响。模型敏感性模拟表明，不同的单层设置中的BC老化参数的MAM4可以导致高达26%和24%的差异，BC负担和辐射强迫，分别。我们还发现，涂层材料的增加（例如，硫酸盐和二次有机气溶胶）通过增加混合物的吸湿性减少了BC的寿命，但增强了其吸收，导致BC直接辐射强迫的净增加。我们的研究结果表明，准确的模拟BC老化过程以及其他气溶胶物种是同样重要的，在减少BC强迫估计的不确定性。
The direct radiative forcing of black carbon aerosol (BC) on the Earth system remains unsettled, largely due to the uncertainty with physical properties of BC throughout their lifecycle. Here we show that ambient chamber measurements of BC properties provide a novel constraint on the crude BC aging representation in climate models. Observational evidence for significant absorption enhancement of BC can be reproduced when the aging processes in the four‐mode version of the Modal Aerosol Module (MAM4) aerosol scheme in the Community Atmosphere Model version 5 are calibrated by the recent in situ chamber measurements. An observation‐based scaling method is developed in the aging timescale calculation to alleviate the influence of biases in the simulated model chemical composition. Model sensitivity simulations suggest that the different monolayer settings in the BC aging parameterization of MAM4 can cause as large as 26% and 24% differences in BC burden and radiative forcing, respectively. We also find that an increase in coating materials (e.g., sulfate and secondary organic aerosols) reduces BC lifetime by increasing the hygroscopicity of the mixture but enhances its absorption, resulting in a net increase in BC direct radiative forcing. Our results suggest that accurate simulations of BC aging processes as well as other aerosol species are equally important in reducing the uncertainty of BC forcing estimation.