Dust-driven droplet freezing explains cloud-top phase in the northern extratropics

• 成果类型: Article
• 署名作者: Villanueva, D.; Stengel, M.; Hoose, C.; Bruno, O.; Jeggle, K.; Ansmann, A.; Lohmann, U.
• 署名单位: Swiss Federal Institutes of Technology Domain; ETH Zurich; Deutscher Wetterdienst; Helmholtz Association; Karlsruhe Institute of Technology; Leibniz Association; Leibniz Institut fur Tropospharenforschung (TROPOS)
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12580
• DOI: 10.1126/science.adt5354
• 发表日期: 2025-07-31
• 页码: 521-525
• 关键词: heterogeneous ice nucleation; mineral dust; desert dust; parameterization; reanalysis; satellite; EVOLUTION; aerosols; water

摘要

Clouds between -39 degrees and 0 degrees 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 degrees and -30 degrees 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.