The Beijing Winter Olympics is a grand event attracting global attention. For this event, a group of scientists and technologists have independently built China's icy snow track, and developed efficient snow storage technology to achieve the freedom to use snow in an eco-friendly way.
From spraying snow, injecting water, compacting snow to measuring and analyzing results, experts have tried hundreds of combinations of water injection techniques and compaction methods, and have made masses of comparative analyses of abundant data. Therefore, Wang Feiteng, a researcher at the Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), said he could still remember the hardships of making icy snow and the joy of making it successfully for the first time.
China started its snow and ice research later than other countries and had little experience holding international snow and ice events. Besides, held in Beijing, a city in the continental monsoon climate zone, the 2022 Winter Olympics faces unfavourable meteorological conditions. And the event is held at the conjunction of winter and spring, which is prone to extreme weather events. In order to provide a good experience for athletes all over the world, Chinese scientists attempted to solve the problem of snow protection.
In 2017, a technology research team focused on snow protection for the Beijing Winter Olympic Games was formally established. The team was led by Qin Dahe, an academician at the CAS and honorary director of the State Key Laboratory of Cryospheric Sciences (SKLC), and Wang Feiteng was also a member.
Ice and snow are “souls” of the past Winter Olympics, and snowmaking, snow preservation and snow storage are the key to ensuring the smooth running of skiing events. However, the related technologies have been monopolized by foreign countries for a long time. “Even the scientific and technological workers like us, who have been engaged in glacier studies and protection, were unfamiliar with many concepts such as the icy snow,” Wang Feiteng recalled. To solve this barrier, the team has been working on snowmaking since 2017.
As Chinese people believe that the empty talk harms the country; while hard work makes it flourish, the team struggled to find its way. In the past, specialized observers were required to forecast the snow quality on tracks. But the process was quite time-consuming and results were not accurate enough. While at present, the team has established dense meteorological observation networks in the Genting Ski Park, a competition zone in Zhangjiakou, Hebei province. Additionally, with the help of snow quality data and other key parameters as well as the snow quality monitoring and forecasting technologies, a model to judge the grade of snow quality was finally developed. And it was put into use during test events in 2021.
Yin Shuiqing, associate professor at the Faculty of Geographical Science, Beijing Normal University, said that it was quite unusual to forecast the snow quality on tracks to kilometre-level resolution in the past, but now the model can accurately forecast the meteorological conditions of different locations of the snow track for the next 72 hours at the hectometer level. Besides, it can dynamically simulate and predict the whole evolution process of snow quality over time. The development of the model also laid a solid foundation for the team to create the icy snow track.
According to Ding Minghu, a researcher at the Chinese Academy of Meteorological Sciences (CAMS), the icy snow is a form of snow quality with a thin layer of ice crust on its surface, which is mainly used to reduce the frictional force of the track surface on the skis. Icy snow track is the “highway” for events such as alpine skiing and giant slalom.
From 2019 to 2021, the research team initiated studies on making icy snow in testing areas such as the Genting Snow Park and the National Alpine Skiing Centre. Those areas were very cold, with temperatures as low as minus 20 degrees Celsius. Wang Feiteng, Ding Minghu and other team members had to work in the frigid conditions for more than 10 hours at a time. “The process sounds as simple as spraying snow and injecting water. But there are no specific parameters for how thick the snow should be or how often water should be added,” Ding mentioned.
Nonetheless, their persistence and hard work eventually paid off. The team independently built icy snow track and professional monitoring equipment for it, including an icy snow hardness tester and an icy snow particle size tester, reducing costs with a green and efficient model for ski track construction in the post-Olympic era.
The storage of 5,000 cubic meters of snow in Big Air Shougang is also inseparable from the efforts of the team. According to diverse meteorological conditions, exposure rates of sunlight and other parameters, experts initially tried different ways including “geotextile plus crop straw”, “geotextile plus sawdust” and “geotextile plus foam plastics” to cover snow. After repeated experiments, the most economical and practical scheme “geotextile plus foam plastics” finally stood out.
“Our snowmaking, snow preservation, snow storage and other snow services all meet the needs of the 2022 Beijing Winter Olympic Games now,” Wang Feiteng added. Nowadays, the snow storage scheme created by Wang and his teammates has been effectively implemented at several ski resorts and events, including the International Ski Federation (FIS) Cross-Country World Cup Skiing Points Series held last May.
Article contributed by Li Jie and Zhang Wenjing, Guangming Daily
Translated by Wang Wenyan and Duan Xuepei, Beijing Normal University