Theoretical framework for measuring cloud effective supersaturation fluctuations with an advanced optical system

<p>Supersaturation is crucial in cloud physics, determining aerosol activation and influencing cloud droplet size distributions, yet its measurement remains challenging and poorly constrained. This study proposes a theoretical framework to simultaneously observe critical activation diameter an...

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Bibliographic Details
Main Authors: Y. Kuang, J. Tao, H. Xu, L. Liu, P. Liu, W. Xu, Y. Sun, C. Zhao
Format: Article
Language:English
Published: Copernicus Publications 2025-01-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/25/1163/2025/acp-25-1163-2025.pdf
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Summary:<p>Supersaturation is crucial in cloud physics, determining aerosol activation and influencing cloud droplet size distributions, yet its measurement remains challenging and poorly constrained. This study proposes a theoretical framework to simultaneously observe critical activation diameter and hygroscopicity of activated aerosols through direct measurements of scattering and water-induced scattering enhancement of interstitial and activated aerosols, enabling effective supersaturation measurements. Advanced optical systems based on this framework allow minute- to second-level effective supersaturation measurements, capturing fluctuations vital to cloud microphysics. Although currently limited to clouds with supersaturations below <span class="inline-formula">∼</span> 0.2 % due to small scattering signals from sub-100 nm aerosols, advancements in optical sensors could extend its applicability. Its suitability for long-term measurements allows for climatological studies of fogs and mountain clouds. When equipped with aerial vehicles, the system could also measure aloft clouds. Therefore, the proposed theory serves as a valuable method for both short-term and long-term cloud microphysics and aerosol–cloud interaction studies.</p>
ISSN:1680-7316
1680-7324