Hu Zhijin, born in March 1935, is from Ningbo, Zhejiang. Since the 1960s, he has been engaged in long-term research on cloud precipitation physics and artificial weather effects. He has won the second prize of the National Science and Technology Progress Award twice and the Fengyun Achievement Award of the China Meteorological Service Association Science and Technology Award in 2024. Formerly served as Vice Chairman of the Academic Committee of the Chinese Academy of Meteorological Sciences, Chairman of the Atmospheric Physics Committee of the Chinese Meteorological Society, and member of the Science and Education Committee of the China Meteorological Administration. It took 18 years to observe the changes of clouds, reveal the secret of clouds becoming raindrops, explore the numerical models of cloud precipitation and weather modification, form the cloud precipitation model series of the Chinese Academy of Meteorological Sciences (CAMS), and lay the foundation of weather modification models in China... This is what Hu Zhijin, an expert in cloud precipitation physics at the China Meteorological Administration, has done all his life. To conduct research on artificial weather modification is to dare to 'ask for water from the sky'. Even if there are many difficulties, we must persevere Hu Zhijin said. Chasing clouds and observing fog on high mountains for 18 years. Many peaks of Mount Lu in Jiangxi are shrouded in clouds and mist all year round. In 1958, the Central Meteorological Administration (predecessor of the China Meteorological Administration) established the original Lushan Weather Control Research Institute in Rizhao Peak, Jiangxi. In 1960, Hu Zhijin came to the research institute to study the changing patterns of clouds and mist on mountain peaks every day, and attempted to catalyze the transformation of thick clouds and mist into rain, moistening the earth. At that time, cloud and fog observation in China was in its infancy. Catalytic clouds first require observing the microstructure of floating clouds in the sky. Clouds are composed of water droplets, which are small but numerous, with approximately 100000 droplets per liter of cloud. After randomly colliding and merging, water droplets in the cloud will continue to grow, and when they reach a certain size, they will fall down under the influence of gravity to form rainfall. If catalytic water droplets continuously collide with small droplets, even if only a small portion of the droplets turn into raindrops and fall down, artificial rain enhancement is considered successful. What kind of clouds are suitable for catalysis, warm clouds or cold clouds? When to catalyze and what catalysis to use? After understanding the microstructure of clouds, Hu Zhijin and his colleagues used a catalytic combustion furnace to search for clouds for catalysis every day. Later, they came up with the method of using hydrogen balloons to observe whether there was any catalytic effect in the clouds. However, the clouds are unpredictable, with their positions and sizes constantly changing. Looking up, Hu Zhijin and his colleagues found that the clouds were on a certain hill. They carried heavy hydrogen cylinders, catalyst combustion furnaces, and other tools to chase after them, but when they reached the hill, they found that the clouds were gone. Unable to catch up with the clouds on the mountain, Hu Zhijin and his colleagues came to the foot of Mount Lu and used a theodolite to assist in measuring the distance of the clouds. Soon, they found that the accuracy of the theodolite was insufficient, and most of the cloud observation locations could only see the bottom of the cloud. So they changed the location for observing clouds from the south to the north of the mountain, set up telephone lines, and borrowed a high-precision theodolite from an external unit. Observe the height of the clouds every minute during the entire process of them becoming larger and wider, rainy, or ice crystals appearing, and take photos with a camera to record the entire process. That's how it was recorded for three years. These solid frontline observation data have filled the gap in convective cloud observation data in China and provided great inspiration for Hu Zhijin. Hu Zhijin and his colleagues initially lived on a mountain at an altitude of 1200 meters, but observations had to be made on the steepest peak. They came to the steepest mountain peak and built their own houses, setting up several gradient observation stations. Living on the mountain, the sound of wild beasts can often be heard at night. Amidst the clouds rising and falling, Hu Zhijin stayed on the mountain for 18 years. Innovative research and development of a new method for artificial precipitation enhancement "In the 18 years on the mountain, the biggest gain is the first-hand observation data on clouds." After analyzing the observation data, Hu Zhijin found that the potential for warm cloud catalysis is not great, and cold cloud catalysis is relatively mature and feasible. This discovery helped the academic community to have a correct understanding of warm cloud catalysis at that time. Hu Zhijin sorted out the microphysical model of cloud to rain that was widely recognized in the world at that time, which was very close to the existing observational results in China. He compared it with other international observation results and found that the ability to catalyze the formation of rain is related to the amount and size of water droplets in the cloud, as well as the speed of cloud ascent. Based on these findings, in 1979, Hu Zhijin wrote a paper titled "Conditions for the Formation of Warm Rain in Cumulus Clouds" and published it in the Journal of Meteorology. In 1978, Hu Zhijin returned to Beijing. At that time, the Chinese Academy of Meteorological Sciences had computers, and there were already artificial precipitation numerical models internationally. I wanted to conduct research on artificial precipitation in China, so that China could also have its own artificial precipitation numerical models and carry out precipitation operations more accurately, "said Hu Zhijin. Hu Zhijin studied meteorology, and when faced with new concepts such as numerical models, he started learning from computer code, carefully designing every equation and continuously improving the accuracy of numerical models. Hu Zhijin found that the international artificial precipitation numerical models are relatively simple, only predicting how high the clouds will be under natural conditions, how much cloud energy will rise after catalysis, and so on. Hu Zhijin began to improve the model by combining China's meteorological conditions and innovatively proposed a microphysical dual parameter model of cloud precipitation particle specific mass plus number concentration. In 1986, he published the research results, which significantly improved the ability to simulate natural and catalytic processes. Based on previous observational data, Hu Zhijin developed a numerical model for catalyzing convective clouds and stratiform clouds, and developed a stratiform cloud system and its catalytic model. This broke through the limitations of the classical theory that artificial precipitation enhancement of stratiform clouds mainly relies on supercooled water, and proposed a new mechanism and method for artificial precipitation enhancement through the condensation and expansion of water vapor and the release of latent heat by artificial ice crystals. Afterwards, Hu Zhijin began to study mesoscale numerical models, similar to weather forecasting. Soon after, he created mesoscale atmospheric cloud resolution and catalysis models, forming the CAMS cloud precipitation model series. Today, the cloud precipitation explicit forecasting system (CMA-CPEFS) developed based on the CAMS microphysics dual parameter scheme is operating in the Artificial Weather Modification Center of the China Meteorological Administration, providing cloud precipitation and catalytic condition forecasts twice a day, providing strong support for various regions to carry out artificial weather modification operation condition forecasting and operation plan formulation. These research achievements have promoted the development of weather modification in China. Hu Zhijin has also won the second prize of the National Science and Technology Progress Award twice, and the first prize and the second prize of the Science Award of the China Meteorological Administration once. Promoting scientific research to better serve production and life, artificial precipitation enhancement, artificial hail suppression...... China's weather modification started in the late 1950s, and Hu Zhijin and other older generation scientific and technological workers need to overcome many unimaginable difficulties. Hu Zhijin has been researching artificial weather modification for over 60 years. He admitted that the driving force of research comes not only from interest, but also from the needs of the development of artificial weather modification in the country and the needs of the people. "People also have great expectations for weather modification. For example, if there is a fire in the forest, if there are clouds above, we can find ways to increase rain, which is more efficient and safer to extinguish the fire." Now, with the joint efforts of generations of meteorological scientists, China's weather modification industry continues to develop, with the scale of operations reaching the first in the world, better serving people's production and life. The scale of homework refers to the scope, intensity, and size of the affected area involved in manual intervention of weather through technological means such as cloud seeding, rain enhancement, and fog elimination, "said Hu Zhijin. Although he is old now, he is very concerned about the progress of scientific research on the front line. Whenever there is an important artificial weather modification operation, he still appears in the consultation room of the Artificial Weather Modification Center of the China Meteorological Administration. I want to know if the numerical model is effective, if there are any problems, whether the observation data is used correctly, and whether the effect is good. "Hu Zhijin guided a group of professional technicians and students. Nowadays, they still frequently seek his advice on relevant technical issues. No matter what research you do, as long as you persist in doing one thing seriously, you will definitely gain something in the end, "said Hu Zhijin. He always encourages students to come up with more ideas and innovate more, only in this way can we promote the continuous progress of artificial weather modification. Perseverance, turning ideals into reality. Working on high mountains, watching clouds rise and fall every day, it looks like 18 years. Having been engaged in meteorological research for over 60 years, Hu Zhijin has never slowed down his pursuit of scientific truth, making research tools, building observation stations, accumulating scientific research data step by step, and finding catalytic clouds and methods step by step... Whether on high mountains or in the laboratory, Hu Zhijin never stops exploring and moving forward. In order to promote the advancement of artificial weather modification technology, older generation scientists such as Hu Zhijin persisted in their research and gradually turned their ideals into reality. As a result, China's weather modification industry has developed rapidly, and has continuously made innovative achievements. The scale of operations has reached the first in the world to better benefit human society. No matter what difficulties we face, we must make unremitting efforts. Hu Zhijin believes that innovative ideas are important, but equally important is perseverance. Only in this way can we continuously overcome difficulties and reap the fruits of science. (New Society)