Effects of a Vertical Cloud Condensation Nuclei Concentration Explosion in an Idealized Hailstorm Simulation

• Published in: Geophysical research letters Vol. 51; no. 8
• Main Authors: Ma, Rongjun, Li, Xiaofei
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.04.2024; Wiley
• Subjects: Aerosols; aerosol‐cloud; Air pollution; Boundary layers; Climate change; Climate prediction; Cloud condensation nuclei; Cloud interaction; Clouds; Condensation; Condensation nuclei; Convection; Convective clouds; Environmental impact; Explosions; Future climates; Hail; Hail formation; Hailstorms; idealized model; microphysics; Nuclei concentration; Nucleus; Numerical experiments; Precipitation; Precipitation rate; Rainfall; riming collection efficiency; Sensitivity; Vertical distribution; vertical level for cloud condensation nuclei concentration; Water vapor; Water vapour; Weather modification
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2024GL108592

Determination of the key vertical level for cloud condensation nuclei concentration (CCNC) explosions has been a long‐term issue in CCN‐cloud interaction studies. An idealized hailstorm is simulated with 37 sensitivity runs, including an initial CCNC grouping vertically from the ground to the cloud top, increasing from 100 to 3,000 mg−1. The results reveal a key zone from 750 to 800 hPa near the median boundary layer, where an explosion of CCNC plays a dominant role in the nonmonotonic response of the hail precipitation rate. The explosion of CCNC in this zone could initially result in the condensation of more water vapor into the clouds, which could be transported to a greater vertical extent to significantly affect the riming collection efficiency. However, the dominant zone for the total precipitation rate is wider at heights of 700–800 hPa due to the lower sensitivity of the riming collection efficiency. Plain Language Summary Aerosols can serve as cloud condensation nuclei (CCN) in the atmosphere, affecting convective clouds, including hailstorms; however, due to their uneven vertical distribution, aerosols are a largely uncertain factor when predicting future climate change. Exploration of the key vertical layer induced by CCN during hail precipitation is an increasingly popular research topic to reduce uncertainty in future convection assessments and to operating accurately during weather modification. In this work, by comparing idealized cloud‐resolving numerical experiments with CCNC explosions in different layers, the 750–800 hPa height, that is, near the base of convective clouds, is the most sensitive zone for determining the effects of CCN on hail. This layer is narrower than that for rain, indicating greater difficulty in predicting hail within an uncertain vertical distribution of aerosols compared to rainfall. Thus, this study advances the understanding of how air pollution impacts the hail formation. Key Points Hail precipitation is highly sensitive to the explosion of cloud condensation nuclei concentration in different vertical layers The exploded cloud condensation nuclei concentration near the median boundary layer controls the sensitivity of hail precipitation The dominant vertical zone of the cloud condensation nuclei concentration effect on hail is narrower than that on rain