High Potential of Asian Dust to Act as Ice Nucleating Particles in Mixed‐Phase Clouds Simulated With a Global Aerosol‐Climate Model
High Potential of Asian Dust to Act as Ice Nucleating Particles in Mixed‐Phase Clouds Simulated With a Global Aerosol‐Climate Model
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DOI：
10.1029/2020jd034263
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
K. Kawai;H. Matsui;Y. Tobo
中科院分区：
文献类型：
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作者：
K. Kawai;H. Matsui;Y. Tobo
矿物粉尘作为冰核粒子（INPs）影响混合相云的微物理和辐射特性，进而影响地球的辐射平衡。然而，亚洲沙尘作为冰核粒子的重要性尚未得到充分了解。在这项研究中，我们使用一个全球气溶胶 - 气候模型，通过一个将冰核粒子数浓度与环境温度和沙尘数浓度相关联的冰核参数化方案，研究了亚洲沙尘对全球沙尘冰核粒子的贡献及其对云辐射强迫（CRF）的影响。我们的模型很好地再现了2017年5月亚洲沙尘输送到日本期间在日本东京都地区测量到的冰核粒子数浓度。我们对2013 - 2017年的模拟显示，亚洲沙尘从其源区（例如戈壁和塔克拉玛干沙漠）延伸到北太平洋、北美洲和北极。值得注意的是，亚洲沙尘比来自其他地区的沙尘更有效地被输送到更高的高度（即输送到与混合相云形成相关的温度区域）。亚洲沙尘对全球沙尘冰核粒子的年平均模拟贡献为15%，比其对全球大气沙尘负荷的贡献（3.4%）高4.4倍。亚洲沙尘的这些特征表明它在混合相云中作为冰核粒子具有很高的潜力。敏感性模拟显示，在2013 - 2017年期间，亚洲沙尘冰核粒子在东亚和北太平洋具有0.054 - 0.19瓦/平方米的正净云辐射强迫（相比之下，来自其他地区的沙尘为0.092 - 1.0瓦/平方米）。
Mineral dust affects the microphysical and radiative properties of mixed‐phase clouds and hence the radiative balance of the Earth by acting as ice nucleating particles (INPs). However, the importance of Asian dust as INPs is not well understood. In this study, we examined the contribution of Asian dust to global dust INPs and its effect on cloud radiative forcing (CRF) using a global aerosol‐climate model with an ice nucleation parameterization that links INP number concentrations to ambient temperature and dust number concentrations. Our model well reproduces INP number concentrations measured over the Tokyo Metropolitan area in Japan during May 2017, when Asian dust was transported to Japan. Our simulation for the years 2013–2017 shows that Asian dust extends from its source regions (e.g., the Gobi and Taklimakan Deserts) to the North Pacific, North America, and the Arctic. Notably, Asian dust is transported to higher altitudes (i.e., to temperature regimes relevant for the formation of mixed‐phase clouds) more efficiently than dust from other regions. The annual‐mean simulated contribution of Asian dust to global dust INPs is 15%, which is 4.4 times higher than its contribution to global atmospheric dust loading (3.4%). These characteristics of Asian dust show its high potential to act as INPs in mixed‐phase clouds. Sensitivity simulations show that Asian dust INPs have a positive net CRF of 0.054–0.19 W m−2 in East Asia and the North Pacific during 2013–2017 (cf. 0.092–1.0 W m−2 for dust from other regions).