Observations suggest that North African dust absorbs less solar radiation than models estimate
Observations suggest that North African dust absorbs less solar radiation than models estimate
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DOI：
10.1038/s43247-023-00825-2
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
A. Adebiyi;Yue Huang;B. Samset;J. Kok
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文献类型：
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作者：
A. Adebiyi;Yue Huang;B. Samset;J. Kok
沙漠尘埃占气溶胶吸收的短波辐射的很大一部分，这增加了温室气体造成的气候变暖。然而，目前还不确定尘埃究竟吸收了多少短波辐射。在这里，我们利用现场测量的尘埃单散射散射的反射率，以限制吸收中可见光波长的北非尘埃，这约占全球尘埃的一半。我们发现气候和化学传输模型将北非沙尘吸收气溶胶光学厚度（AAOD）高估了两倍。这主要是因为模型高估了尘埃的假想折射率，其影响部分被低估的大尘埃颗粒所掩盖。类似的因素可能会导致高估的AAOD检索的气溶胶机器人网络，这是常用的评估气候和化学运输模式。模型对灰尘吸收的高估可能导致模拟灰尘对地球系统影响的重大偏差，包括灰尘辐射效应的暖偏差。
Desert dust accounts for a large fraction of shortwave radiation absorbed by aerosols, which adds to the climate warming produced by greenhouse gases. However, it remains uncertain exactly how much shortwave radiation dust absorbs. Here, we leverage in-situ measurements of dust single-scattering albedo to constrain absorption at mid-visible wavelength by North African dust, which accounts for approximately half of the global dust. We find that climate and chemical transport models overestimate North African dust absorption aerosol optical depth (AAOD) by up to a factor of two. This occurs primarily because models overestimate the dust imaginary refractive index, the effect of which is partially masked by an underestimation of large dust particles. Similar factors might contribute to an overestimation of AAOD retrieved by the Aerosol Robotic Network, which is commonly used to evaluate climate and chemical transport models. The overestimation of dust absorption by models could lead to substantial biases in simulated dust impacts on the Earth system, including warm biases in dust radiative effects.