Spatial and Temporal Variability of Brown Carbon in the United States: Implications for Direct Radiative Effects
Spatial and Temporal Variability of Brown Carbon in the United States: Implications for Direct Radiative Effects
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DOI：
10.1029/2020gl090332
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发表时间：
2020-11
影响因子：
5.2
通讯作者：
N. June;Xuan Wang;L. Chen;J. Chow;J. Watson;Xiaoliang Wang;B. Henderson;Yiqi Zheng;J. Mao
中科院分区：
文献类型：
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作者：
N. June;Xuan Wang;L. Chen;J. Chow;J. Watson;Xiaoliang Wang;B. Henderson;Yiqi Zheng;J. Mao
来自受保护视觉环境机构间监测 (IMPROVE) 观测网络的新开发的数据集与 3D 化学传输模型相结合，用于评估美国棕碳 (BrC) 的时空变化。生物质燃烧和生物燃料排放中排放的 BrC 模型与 BrC 行星边界层 (PBL) 吸收气溶胶光学深度 (AAOD) 观测值的季节和空间变化一致，误差在 2 倍以内。该模型没有白化，吸收随气溶胶老化而减少的趋势，高估了观测到的 BrC PBL AAOD，并且没有反映测量到的 BrC PBL AAOD 空间变异性。该模型显示，由于北方火排放、长白化寿命和高表面反照率，春季和夏季北部高纬度地区的 BrC 吸收直接辐射效应 (DRE) 高于中纬度地区。这些发现凸显了研究北极地区 BrC 的必要性。
A newly developed data set from the Interagency Monitoring of PROtected Visual Environments (IMPROVE) observation network, combined with a 3‐D chemical transport model, is used to evaluate the spatial and temporal variability of brown carbon (BrC) in the United States. The model with BrC emitted from biomass burning and biofuel emissions agrees with the seasonal and spatial variability of BrC planetary boundary layer (PBL) absorption aerosol optical depth (AAOD) observations within a factor of 2. The model without whitening, the tendency for absorption to decrease with aerosol aging, overestimates the observed BrC PBL AAOD and does not reflect the measured BrC PBL AAOD spatial variability. The model shows higher absorption direct radiative effects (DRE) from BrC at northern high latitudes than at midlatitudes in spring and summer, due to boreal fire emissions, long whitening lifetimes, and high surface albedos. These findings highlight the need to study BrC over the Arctic region.