China News Service, Beijing, August 24 (Wei Xianghui) Recently, affected by high temperature weather, various provinces and cities, especially in the Yangtze River Basin, have issued announcements on artificial rain enhancement operations.
As one of the technical means of artificially affecting the weather, the effect of artificial rainfall depends on certain natural conditions.
Faced with the complex climate environment in today's world, experts say that more rigorous scientific experiments are needed to deal with nature.
Data map: Photo by Ivan of Rain Enhancement Rocket Launch
Drought hits the south
Artificial rain-enhancing planes support drought relief
On the 23rd, the news that the China Meteorological Administration dispatched an artificial rain-enhancing plane to Chongqing was posted on Weibo.
According to the CCTV news client, the plane arrived in Chongqing at 16:00 on the 23rd, waiting for the precipitation weather system to enter Chongqing.
Since July this year, the city's average temperature has been the highest since 1961, and the city's average precipitation has also been the lowest since 1961.
In addition, Sichuan, Hubei, Hunan, Anhui and other cities in the Yangtze River Basin continued to have high temperatures and little rainfall, and even experienced droughts that were rare in the same period for many years.
According to a report by Hubei Daily on the 17th, Hubei has urgently allocated 5 million yuan in special funds for artificial rain enhancement and drought relief.
After consultation between the Hubei Provincial Government and the China Meteorological Administration, the China Meteorological Administration urgently coordinated a national high-performance artificial rain enhancement aircraft to assist Hubei.
From 8:00 on the 15th to 20:00 on the 16th, the Hubei Meteorological Department carried out a total of 159 ground artificial rainfall operations in Shiyan, Xiangyang, Enshi, Yichang, Shennongjia, Suizhou, Xiaogan, Huanggang, Huangshi, Wuhan, Ezhou, Xianning and other areas. The affected area of the operation is about 25,800 square kilometers.
On the 22nd, the China Meteorological Administration connected with the meteorological bureaus of Gansu, Shaanxi, Sichuan, Chongqing, Guizhou, Henan, Hubei, Jiangxi, Inner Mongolia and other provinces (autonomous regions and municipalities directly under the Central Government) to summarize the preliminary weather modification work, analyze and judge the conditions of subsequent precipitation enhancement operations. And condolences to the staff who support Hubei's rain enhancement operations.
Zhang Zuqiang, a member of the party group and deputy director of the China Meteorological Administration, said that it is necessary to continue to improve the national-provincial linkage mechanism to achieve scientific, accurate and safe operations, and make due contributions to combating high temperature, drought resistance, and ensuring a bumper harvest.
The China Meteorological Administration dispatched a high-performance aircraft to assist Chongqing in rain enhancement and drought relief work.
Photo courtesy of Chongqing Meteorological Bureau
High temperature and drought are mainly affected by the subtropical high
Artificial precipitation is not a panacea for "fever reduction"
Artificial precipitation, also known as "artificial rainfall".
In this regard, Yin Yan, a professor at the School of Atmospheric Physics, Nanjing University of Information Technology, explained to Chinanews that the two expressions mean the same thing. A large number of artificial ice nuclei are re-melted to form ice crystals, which then grow to a certain extent through condensation/sublimation and deposition to form precipitation particles that fall to the ground.
But the expression of artificial precipitation is more scientific.
Yinyan said that this year's high-temperature and arid areas continue to be controlled by the subtropical high pressure, and the macro- and micro-structure of clouds generally do not have the conditions for artificial precipitation.
"Under the control of the subtropical high for a long time, the sky is generally less cloudy or there is no cloud at all. The primary condition for artificial rainfall is that there must be clouds, and it is impossible to artificially create clouds. If there are clouds, the temperature during the day will not reach that extreme. high value," he said.
In the absence of clouds, the effect of artificial precipitation is very limited.
According to Guiyang's release, on the 21st, precipitation clouds appeared in some areas of Guiyang City. The Guiyang Meteorological Bureau carried out artificial rainfall enhancement and drought relief operations, but it was not enough to "quench thirst".
According to the weather radar detection analysis, it is concluded that the overall water content of the cloud layer is not high, and the artificial precipitation conditions are very limited.
After the operation, under the combined effect of natural precipitation and artificial precipitation, a total of 34 rainfall stations have monitored precipitation, and the measured maximum millimeter precipitation is 1.7 mm.
However, with the advent of cold air, some cities in the Yangtze River Basin have experienced precipitation, which provides an opportunity for the implementation of artificial precipitation.
Yin Yan introduced that if the rainy season comes, or the cloud system conditions are better, then the natural precipitation may be relatively sufficient. On this basis, adding some artificial ice cores can further increase the precipitation.
Affected by the combined influence of rainfall and low-level cold air infiltration, the high temperature weather in Jianghan, Jianghuai and other places has been relieved first.
According to the WeChat public account "released by the People's Government of Hefei City" on the 23rd, as the rain falls, Feidong County, Chaohu City, Feixi County, Lujiang County and Changfeng County will all choose the opportunity to carry out artificial rain enhancement operations.
Wanzhu District, Wuhu City also stated in the weather modification operation announcement issued on the 22nd that it will seize all favorable conditions to continue artificial rain enhancement operations.
The picture shows the Jiaxiu Building in Guiyang, taken on the 19th.
Photo by Qu Honglun
Extreme weather may occur frequently in the future
Artificial weather modification still needs to increase scientific experiments
Yinyan told Chinanews that in the past, areas prone to drought in China were concentrated in the north, so large-scale artificial rainfall enhancement operations were mostly carried out in the area north of the Yangtze River.
In recent years, artificial rainfall has also been carried out in the south of the Yangtze River.
In the future, if global warming is further intensified, the melting of the polar glaciers will accelerate, and various extreme weather may occur frequently.
There is a consensus that human activities will have an impact on the climate. For example, the global warming that is currently being experienced is related to the emission of large amounts of greenhouse gases such as carbon dioxide by humans.
Yin Yan introduced that climate change can be reversible or irreversible, and the cycle is long.
In order to reduce meteorological disasters, make rational use of climate resources, and artificially affect the physical and chemical processes of the local atmosphere through scientific and technological means under appropriate conditions, to achieve the purpose of increasing rain and snow, preventing hail, eliminating fog, and preventing frost. Affect the weather, including artificial rain increase, artificial frost prevention, artificial cloud reduction and rain reduction, artificial hail prevention and artificial fog elimination.
In 1958, in response to the severe drought in Jilin, China conducted the first artificial aircraft rain enhancement operation.
Over the past 60 years, China's weather modification business system has been gradually improved.
In December 2021, the Weather Modification Center of the China Meteorological Administration was formally established, proposing to strengthen scientific and technological support and business guidance for weather modification work across the country.
"China is currently in a leading position in the world in terms of manpower, material and financial resources, technical level and application scale in artificial weather modification." Yin Yan believes that this is related to China's geographical environment, climate and per capita fresh water. In addition, China is an agricultural country, and agricultural irrigation water consumption is large.
He said that timely artificial rain enhancement can supplement the water storage of lakes and is beneficial to the ecological environment.
Although the silver ions in the silver iodide used are heavy metals, due to the small amount and the large dispersion area, the unit content of silver iodide scattered on the ground and in the air is very small.
Therefore, there is no need to worry about the environmental pollution caused by artificial rainfall, on the contrary, it can also play the role of optimizing air quality, pressing dust for cleaning and reducing the level of fire danger.
In terms of funding, compared with agriculture and drought resistance, artificial rainfall is only a small part.
However, in Yinyan's view, artificial weather modification is still in the stage of scientific experimentation, and it can be effective under suitable conditions, but it has not yet reached the level of effective operation.
"Dealing with the natural world, especially atmospheric science, will have all kinds of unexpected consequences. Only through unremitting scientific research, exploring the laws of nature, and artificially influencing them on the basis of understanding." He said, "It is impossible to rely solely on Artificial will, dealing with the natural world is not like this." (End)