Mobilizing Citizen Science for Hailstorm Research: Motivations, Challenges and the Outcomes

Citizen science has already been used for hazard-based data collection globally including storm, flood and air-pollution. Here we present a citizen science demonstration project of HIWeather (High-Impact Weather project) under WWRP, which aimed on hailstone collection from 2016 to 2024, reviewing its scientific objectives and results, public motivation and participation, challenge and future prospects.

The project was setup to fully understand how aerosols interact with moisture in the growth process of hailstone from 2016. As hailstorm are mesoscale deep convection with high social-impact and low predictability, it is hard for researcher to collect nature hailstone before melting. However, citizen science provide a possible solution in China, considering its dense population. The online platform of WeChat was leveraged to broadcast the collection needs, engage the public, and provide detailed instructions for sample collection. The project has successfully gathered 3,063 freshly fallen hailstones from 15 provinces in China by 100 times of voluntary collections.

Hailstones after local hailstorms are collected by volunteers, and stored properly until delivered for further laboratory analysis. After pre-processing, hailstone samples were analyzed to determine their chemical composition, including water-soluble ions, stable isotopes, and insoluble particles from inner embryos to outer shells. Analysis revealed that the major source of water-soluble ions and insoluble particles in hailstones are likely come from local surface aerosols, and multiple hailstone growth trajectories exist in deep convection. The analysis of the collected samples has yielded valuable information on aerosols and the growth trajectories of hailstones. The results provide insights into hailstone formation processes and highlight the importance of atmospheric chemistry in predicting hailstorm in the future.

To foster mutual benefits and encourage future engagement, follow-up communication with contributors is upheld to express gratitude, acknowledge achievement, and gather feedbacks. Surveys indicate that most responded volunteers (79%) are primarily motivated by contributing to science, with a good scientific literacy through general education and science outreach efforts. Motivation from direct experience of hail damage is notably with 67% respondents reported that. Widespread use of smartphones and social media is crucial to extended information network and booster citizen science project mobilization.