## 1 Introduction  
Stratospheric ozone accounts for approximately 90% of the total ozone in the world and can absorb most of the short-wave ultraviolet rays of the solar rays, thus greatly reducing the intensity of solar ultraviolet radiation reaching the ground. The excessive consumption of stratospheric ozone will lead to the increase in ultraviolet radiation exposure of the biosphere, including human beings, and threaten human life and health [1; 2; 3; 4; 5]. In addition, the absorption of ultraviolet radiation by stratospheric ozone will also heat the stratospheric atmosphere, and then affect the temperature field and circulation field of the stratosphere, which is very important to the entire Earth system [6; 7]. In 1985, [PERSON] et al. revealed for the first time that the Antarctic stratospheric ozone has been sharply decreasing every spring since the late 1970s, and the trend in ozone reduction continues to strengthen. In 1987, the United Nations invited 26 member states to sign the Montreal Protocol on Substances that Deplete the Ozone Layer, which aims to prevent the continued depletion of the ozone layer [8; 9; 10]. Since this time, improved observational techniques, especially the launch of satellites, have allowed researchers to more accurately study ozone at all altitudes across the globe [11; 12; 13; 14; 15; 16; 17; 18; 19]. The researchers found a low ozone value region similar to the Antarctic ozone hole in the upper troposphere-lower troposphere (UTLS) region in the middle and high latitudes of the Northern Hemisphere, known as the \"Ozone Valley\". This concept was initially proposed by [PERSON] and [PERSON] [20], and the valley predominantly spans areas near two major mountain ranges, namely the Tibetan Plateau (TP), known as the third-level roof of the world, and the Rocky Mountains in North America. Between these two ozone valleys, the ozone valley over the TP is the most profound, characterized by the lowest local atmospheric total column ozone (TCO) compared with the areas of the same latitude, especially in summer. Analysis using TOMS (total ozone mapping spectrometer) data has revealed the ozone valley in the TP is formed in summer (June-September), during which time, the discrepancy in the ozone content between the TP and the eastern region at the same latitude could reach 11%. The significantly low TCO values over the TP have substantially diminished the absorption effect of ozone on solar ultraviolet radiation. Consequently, the ultraviolet radiation reaching the surface is significantly strengthened. In addition, the local snow and rock surfaces, which strongly reflect ultraviolet light, cause Tibet to have a high incidence of cataracts. Therefore, it is very important to study the factors affecting the \"ozone valley\" of the UTLS layer in the TP region. Researchers have extensively studied the phenomenon and causes of the ozone valley over the TP [21; 22; 23; 24; 25; 26; 27]. [PERSON] et al. [22] found that the center of the ozone valley is located near the tropopause, with an intensity of approximately \(-15\) DU, and the other sub-strong center is located in the upper stratosphere with an intensity of \(-8\) DU. [PERSON] et al. [28] preliminarily speculated that the dynamic process caused by the special topography of the TP may contribute to the formation of the ozone valley. By studying the characteristics of vertical circulation over the TP, researchers also found that the dynamic and thermal effects of the TP in summer played very important roles in the formation of low-value ozone centers [29; 30]. Under the influence of the strong South Asian High (SAH), the updraft of the TP region will form a large amount of divergence in the stratosphere, resulting in a decrease in ozone concentration, while the chemical effect is minimal in this process.