What are the cities with the strongest ultraviolet rays in China? What are the cities with the weakest ultraviolet rays?
The strongest ultraviolet rays in China are in Lhasa, Qinghai-Tibet Plateau, Guizhou, Hangzhou, Lhasa and Guangxi.
The relatively low level in the southeast of the mountainous area around Sichuan Basin is conducive to the entry of water vapor, while the relatively high level in the northwest mountainous area is not conducive to the loss of water vapor, resulting in high air humidity, rainy and foggy weather, which is the area with the least annual sunshine time and the weakest ultraviolet rays in China. Because of its high altitude, the Qinghai-Tibet Plateau has relatively dry and thin air, strong solar radiation and the strongest ultraviolet rays.
Extended data:
The weakest ultraviolet rays in China are Harbin, Xi, Kunming, Chengdu and Chongqing.
The strongest ultraviolet rays in China are in Lhasa, Qinghai-Tibet Plateau, Guizhou, Hangzhou, Lhasa and Guangxi.
The ultraviolet intensity is mainly affected by the following factors:
1, geographical latitude. The change of radiation intensity is indirectly affected by affecting the height of the sun and the sunshine time. In winter (65438+1October), the solar altitude angle in Chinese mainland gradually decreases from south to north, resulting in the radiation intensity gradually decreasing from south to north. The highest radiation intensity in summer (July) mainly appears in North China and Northwest China where the sun is high and the sunshine time is long. The radiation intensity in South China and southern Qinghai-Tibet Plateau is relatively low.
2. The "three steps", especially the basic topographic pattern of the Qinghai-Tibet Plateau, has an important influence on the spatial distribution pattern of biologically effective ultraviolet radiation. From the southeast coast to the northwest inland, the radiation intensity gradually increases with the elevation. The Qinghai-Tibet Plateau is the highest altitude area in China. In June+10/October, 5438, it was found that there was an ozone "low valley" in the stratosphere over the Qinghai-Tibet Plateau, which reduced the absorption and scattering of ultraviolet radiation. Therefore, the Qinghai-Tibet Plateau is the high value area of biologically effective ultraviolet radiation intensity in China in June+10, 5438.
3. Scattering effect of cloud on ultraviolet radiation. In June+10, 5438, the clouds in Sichuan Basin and Yarlung Zangbo River Gorge in the south of Qinghai-Tibet Plateau were relatively large, and the daily radiation intensity was obviously lower than that in surrounding areas. In July, the amount of clouds in the south of Qinghai-Tibet Plateau, the west of Yunnan-Guizhou Plateau and Hengduan Mountain was greater than that in South China at the same latitude, resulting in the daily radiation intensity being lower than that in South China. ?
4. Selective absorption of ozone. The absorption degree of ozone to U VB is much greater than that of U VA, which leads to that the high value of daily radiation intensity distribution of UVB in July in China is obviously lower than that of UVA.
5. The weighting coefficient of effective radiation of 5.U VA biomass relative to 270 nm radiation is much smaller than that of UVB.