Do you know how to choose a "satisfactory" snow when making snow? Although all of them are artificial snow, the snow is also divided into 9 models, the smaller the number, the closer it is to powder snow, and the larger the snow, the wetter it is. It is really not an easy task to create the right snow according to different temperatures and different track requirements.
On December 28, Nandu reporters came to the National Biathlon Center, which is located in the valley northeast of Zhangjiakou Olympic Sports Park, the valley as a whole is high in the east and low in the west, and the track relies on natural terrain. From December 28th to 31st, about 30 wax engineers from about 8 national Olympic committees came to the Zhangjiakou National Biathlon Center for snow wax testing and detected the snow quality here in advance.
Snowmaking expert Wei Qinghua. Nandu reporter Wang Fan photographed
The one who directly affects the snow quality of the track is Wei Qinghua's mountain operation team. "Our main job is snowmaking, snow press, ice making, ice cutting, as well as site safety, site setting and material transportation." As the mountain operation manager of the Zhangjiakou Ancient Poplar Tree Stadium, Wei Qinghua has nearly 20 years of snowmaking experience and is an uncompromising snowmaking expert.
How to ensure the good snow quality of the Olympic games? What is the difference between artificial snow and natural snowfall? What is the impact of extreme weather on snowmaking? What should I do if the snow melts in high temperatures? All kinds of questions related to snowmaking in the Winter Olympics were answered in his mouth.
The Winter Olympic ski slopes are being artificially snow-made. Xinhua News Agency
How to ensure the good snow quality of the Olympic games?
According to Wei Qinghua, the snowmaking work in biathlon has lasted for 6 weeks overall, and the basic snowmaking work on all tracks has been completed. The snowmaking area is about 125,000 square meters, with about 60,000 tons of water and 105,000 cubic meters of snow.
How much snow can a ton of water convert into? Wei Qinghua said that under normal circumstances, the water and snow conversion ratio is 1:1.7, that is, one ton of water can produce 1.7 cubic meters of snow.
In addition to artificial snowmaking for the track, there is also landscape snowmaking. "Our track is basically 6 meters wide. When the snow is blown, the snow drifts away, and about 60% of the snow covers the perimeter of the slope. Of course, the snow is not in vain, on the one hand, the bare places are covered, avoiding wind and sand from eroding the track, and also improving the atmosphere of the venue. Wei Qinghua said.
"Good snow quality means providing good water quality." Wei Qinghua said that in order to create good white snow for the Olympic games, the surface runoff will enter a sediment pool before entering the reservoir. Another key step before entering the snowmaking system is to enter a 3500 cubic meter purification tank for filtration.
The National Biathlon Centre ushers in International Training Week. Participants glide on the National Biathlon Center Circuit on December 28. Xinhua News Agency
How to pick the 9 types of snow and which one to use?
Wei Qinghua said that the snowmaking team uses the Italian natural ice snowmaking system, which has a global market share of 60%, which shows its excellent quality, and the snowmaking terminal uses the TF10 snow cannon. The snowmaking work in the biathlon was started for 6 weeks, and at the most, 26 snow machines were put into the site at the same time to ensure a high snow production.
According to him, snowmakers have a characteristic. "It has 9 types of snow, No. 1 to No. 9, the smaller the number, the better the snow quality, that is, powder snow, to No. 9 snow is relatively wet." We used No. 3 snow most of the time on the grounds. He explained that which model of snow to choose is also related to temperature. For example, some time ago, the temperature was high during the day, and the snow of the trumpet was used, with less water content and less snow. When it reaches minus twenty degrees at night, use No. 7 snow and No. 8 snow, so that the snow quality is better.
In general, if the moisture content of snow is too high, the harder it is. "Therefore, we still use snow 3 and 4 snow as much as possible, which are stored for a long time and can ensure a good snow quality during the race." He said.
The National Biathlon Centre ushers in International Training Week. Participants glide on the National Biathlon Center Circuit on December 28. Xinhua News Agency
What is the difference between natural and artificial snow?
"You can see snow that naturally falls, but you don't see artificial snow." Wei Qinghua said that artificial snow and natural snow are quite different.
Artificial snow is more precisely "ice particles", snowmaking is the process of water spraying out through high-pressure atomization, falling in the cold and then crystallizing, if you stand next to the machine, you can feel Xiaoice particles snapping and falling on the body, the hardness is relatively higher. After the natural snow falls, it will age after two weeks or more, and under the action of sunlight and wind, it will age into a sugar-like, loose structure.
Wei Qinghua also revealed that in order to ensure the quantity and quality of snow, artificial snow will be used even if the Olympic events are held in the oceanic climate zone with a large amount of snowfall.
This is the track of the National Biathlon Center in Zhangjiakou, taken on December 23 (drone photo). Xinhua News Agency
What is the relationship between the snowmaking team and the wax master, and why avoid temporary snowmaking as much as possible?
Throughout skiing, waxing is a very technically demanding job and is seen as the "shadow hero" behind the skiers. In general, waxing an athlete's ski equipment can be thought of as applying a layer of lubricant to ensure that the coefficient of friction between the snowboard and the snow surface becomes smaller. How important is this work? There is a fine quantitative statement that the work of a waxer can help skiers improve their performance by 5%-10%.
Waxing and snowmaking teams are also very closely related. "When wax masters come here, they must grasp our altitude, temperature and humidity in advance, and detect the snow quality here, which will greatly affect their waxing work." The waxer will select the type of ski wax according to the snow temperature and the snow quality.
This is also why Wei Qinghua said, "We will not make snow temporarily unless we have to." "Fresh snow and old snow are not the same structure, then the snow quality will change, and the wax master's work will also be adjusted."
During the snow wax test, the Mountain Genting team will also send a special coordinator to work in the wax division team to exchange relevant parameters of the snow and also draw some opinions to prepare for the subsequent optimization and improvement.
On December 28, the runners slid on the National Biathlon Center Track. Xinhua News Agency
What should I do if I experience extreme weather?
Hosting the Winter Olympics in the continental monsoon climate zone, the 2022 Beijing Winter Olympics is the "first time" in the history of the Winter Olympics. Every year from February to March, Beijing and Zhangjiakou are the transition seasons between winter and spring, what challenges does this bring to snowmaking?
"I have been working here for 19 years, and generally the temperature of the snow field in Zhangjiakou in February is more suitable, the wind is not strong, the skiing experience is better, and there will be a lot of melting after entering March." Extraordinary years also feature decades-old high-temperature snowmelt and inversion. After encountering the 60-year high temperature snow melt last year, Wei Qinghua deeply realized, "Whether we say anything about the heavens, then we will add a certainty." ”
Therefore, after the completion of the basic snowmaking, the task of the mountain operation team is not over, and one of their important tasks is to reserve the snowmaking. "We are going to use about 30,000 tons of water to reserve snowmaking, which is about 56,000 cubic meters, especially for the winter Paralympic venues that start in March, and store them at multiple points."
Cope with hot weather, in addition to storing snow, there is also salt. The salt sprinkling is mainly to harden the snow, the team prepared a salt spreader, and purchased 4 tons of large, medium and small grain salt to cope with the special situation of high temperature snow melt disposal.
Nandu reporter also noticed at the scene that there is a certain area of the biathlon field that belongs to the sunny side. Wei Qinghua said that since more than 60% of the snow areas here are sunny, and the snow areas of the shade and the sunny side can have a one-month difference, the mountain genting team has increased the snow thickness, such as the average snow thickness of cross-country skiing venues of 60 centimeters, which is set at 80 centimeters on the winter biathlon track. The extra 20 centimeters is considering the length of the schedule and the problem of more sunny faces.
On December 27, the staff worked at the National Biathlon Center in Zhangjiakou Division. From December 28th to 31st, the National Biathlon Center in Zhangjiakou of the Beijing Winter Olympics will usher in the International Training Week. Xinhua News Agency
What are the differences in snowmaking schemes for different snow projects?
The poplar cluster includes the National Ski Jumping Center, the National Cross-Country SkiIng Center and the National Biathlon Center. As the mountain operation manager of the ancient poplar tree stadium group, Wei Qinghua said that the snowmaking scheme of different snow projects is also very different.
The National Ski Jumping Centre does not make much snow, but the work is demanding. For example, it has a place with a slope of 33.6 degrees, and the following is artificial turf, and in this place, snow is carefully cultivated, otherwise the snow will slide down if you are not careful.
Before making snow, the first step is to clean up the natural snowfall, and this process alone takes 10 days. "If the natural snow is not cleaned up, artificial snow and natural snow together become 'two skins'." For example, he said, it is like making dumplings to put too much "dough", can not be kneaded together at all, can only "cleanse" the snow first.
At the biathlon track, you can see "snow bags" everywhere, which are first made in piles of snow and then spread out on the slopes. Snowmaking on the landing slopes of the National Ski Jumping Center is not possible, and if you do not pay attention to the snowdrifts, they will slip off due to gravity, so it is necessary to make snow evenly "with the method of sprinkling pepper noodles".
In addition to "sprinkling pepper noodles", it is also necessary to pay attention to the control of snow humidity. Compared with the use of No. 3 snow in biathlon, the unique structure of the National Ski Jump center requires a foundation from the bottom up and then pushes upwards, including snow with relative humidity at No. 5 and No. 6.
According to reports, the snowmaking thickness of the landing slope of the National Ski Jumping Center is 45 cm, which is divided into three levels: the grassroots, the middle layer, and the surface layer. The snow weighs 600-700 kg per cubic meter at the base, 500-600 kg in the middle layer and 400-500 kg on the surface. "The snow quality should take into account that the bottom is wetter, the water content is more, and it can be better frozen with the snow below, while the surface snow needs to have less water content to ensure a certain degree of looseness and flatness." Wei Qinghua explained.
The ancient poplar tree stadium group in Zhangjiakou Division is ready to be "inspected". On November 25, the staff operated machinery and equipment to mold snow on the landing slope of the National Ski Jumping Center "Snow Ruyi". Xinhua News Agency
Chongli lacks water, will the competition water use affect the production and life of residents?
As early as the bid for the Beijing Winter Olympics, a question was raised: Chongli area is short of water, how to ensure that the water used for the event and the water used by residents for production and living are not in conflict?
Wei Qinghua said that the current snowmaking water mainly relies on 200,000 tons of reservoirs, which store surface runoff and natural precipitation for snowmaking, "These waters only account for less than 1% of our area." ”
In addition, there are 5 landscape lakes in the biathlon area, with a storage capacity of 50,000 tons. Some of the melted snow water at the end of the snow season will be returned to the reservoir and landscape lake through the underground pipe network, and in addition to considering the water used for the event, the water of the reservoir is also used for green landscape and agricultural irrigation, so that it can be used sustainably.
Nandu reporter Wang Fan sent from Zhangjiakou Chongli