近日，瑞士苏黎世联邦理工学院D. Villanueva团队
介于-39°C和0°C之间的云顶部可能有一层液体或冰层，这会影响它们的辐射强迫和降水。云顶冰-总频率（ITF）量化了有冰的云相对于总云的出现频率，但控制ITF的因素了解甚少。
利用35年的卫星数据，研究组表明，在北半球，在-5°和-30°C之间，气溶胶在时间和空间上都与ITF密切相关。此外，研究组发现ITF（红外传输函数）对温度和尘埃的敏感度比例与液滴冻结的实验室测量结果一致，这表明ITF可归因于尘埃气溶胶。
附：英文原文
Title: Dust-driven droplet freezing explains cloud-top phase in the northern extratropics
Author: D. Villanueva, M. Stengel, C. Hoose, O. Bruno, K. Jeggle, A. Ansmann, U. Lohmann
Issue&Volume: 2025-07-31
Abstract: Clouds between 39° and 0°C can be topped by a liquid or ice layer, which affects their radiative forcing and precipitation. The cloud-top ice-to-total frequency (ITF) quantifies the occurrence of clouds with an ice top relative to total cloud occurrence, but the factors controlling ITF are poorly understood. Using 35 years of satellite data, we show that in the Northern Hemisphere, between 15° and 30°C, dust aerosol is strongly correlated with ITF in both time and space. Furthermore, we found that the sensitivities of ITF to temperature and dust are in a ratio that agrees with laboratory measurements of droplet freezing, showing that ITF can be attributed to dust aerosol.
DOI: adt5354
Source: https://www.science.org/doi/10.1126/science.adt5354