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报告时间 December 16, 2020 (Wednesday) 14:20-16:30 报告地点 Conference Room 927, South Building, Meng Minwei Science and Technology Building, Tsinghua University
主 讲 人 Professor Mao Jietai

Brief Introduction of the Lecture:

Atmospheric water cycle is one of the most important cycles in the earth's atmospheric system, which is a cycle of energy and a cycle of matter, and is the main source of clean water on the earth. Because the atmospheric water cycle directly includes the precipitation process, it is also the key factor to determine the climate characteristics of various regions. According to the principle of conservation of atmospheric moisture, the maximum possible precipitation in a certain period of time in a certain area depends on the total cloud water amount in this area during this period, which is called precipitation potential (or cloud water resources). It is determined by atmospheric dynamic processes and involves great energy requirements, so that human beings are generally unable to interfere with it. But whether these cloud water can become precipitation depends on the cloud microphysical process in the cloud, that is, whether it can merge small cloud droplets into raindrops in time. Because this process does not involve the demand for energy, it is the main entry point of artificial precipitation enhancement. In the operation of artificial precipitation, it is necessary to understand the transformation state from aerosol particle size distribution to cloud droplet size distribution and then to raindrop size distribution, so the detection of the vertical distribution of particle size distribution is put forward high requirements. The detection method of aerosol particle profile by multi-wavelength radar developed in recent years provides a good means for this study.

Brief introduction of the presenter:

Mao Jietai, professor in the Department of Atmospheric and Oceanic Sciences, Peking University, graduated from the Department of Geophysics, Peking University in 1962, majored in Atmospheric Physics, and taught in the department for a long time, including atmospheric radiation and optics, cloud physics, atmospheric chemistry, atmospheric aerosols, and global environment. From 2000 to 2008, he was the director of the Atmospheric Physics and Weather Modification Committee of the Chinese Meteorological Society. The research work is mainly concentrated in the fields of atmospheric optics and cloud physics. Since 1970, he has been doing the observation of sky brightness distribution, and the development and application of one-dimensional cumulus numerical model. Since 1980, his research turned to the problems of atmospheric aerosol and acid rain, during which a high-resolution solar spectrometer was developed for measuring atmospheric trace gases, and the instrument was carried to the Great Wall Station in Antarctica from 1988 to 1989 for observing the column contents of O3 and NO2. Since 1995, the main research work has been focused on the remote sensing of atmospheric water vapor by ground-based GPS and the retrieval of aerosol optical depth from MODIS data, and their applications to the monitoring of mesoscale weather processes and atmospheric environmental quality. Recent research work is mainly on weather modification and the application of remote sensing technology in atmospheric science.