Pre‐Activation of Ice Nucleating Particles in Deposition Nucleation Mode: Evidence From Measurement Using a Static Vacuum Water Vapor Diffusion Chamber in Xinjiang, China

Abstract

AbstractPre‐activation of ice nucleating particles (INPs) is a potential mechanism to enhance ice generation in mixed‐phase clouds, but evidence of INP pre‐activation is still limited. In this study, the pre‐activation of INPs in deposition mode is investigated using refreezing experiments in a static vacuum water vapor diffusion chamber with aerosols sampled in Xinjiang, China. The results indicate that the activation efficiency of INP was enhanced after pre‐activation. Statistically, the INP concentration increased by 266%, 112%, and 70% at −10°C, −14°C, and −17°C after pre‐activation, and more than half of the samples showed an increase in INP concentration. The increase in INP concentration has a positive correlation with the primary INP concentration before pre‐activation. The analyses provide new evidence that the pre‐activated INPs can act as better nuclei at temperature as warm as −10°C, and highlight the importance to find a way to consider this mechanism in models.