Weather conditions in Ya 'an in June, July, August and September 20 10

Ya 'an City, Sichuan (102.9 E, 29.9 N) is located in Sichuan Province and is a famous "rainy city" in China. The annual rainfall days in Ya 'an City are more than 240 days, with three days and two rains. The annual average sunshine 1005 hours, and the daily average sunshine is only 2.8 hours. Especially in summer, there are more rainy days. In some years, it rains almost every day, with frequent rainstorms. Therefore, Ya 'an City is also known as "the city where the sky leaks".

The reason for the rain in Ya 'an City is mainly the result of the influence of the large terrain on the Qinghai-Tibet Plateau. Ya 'an City is located on the leeward slope at the eastern foot of Qinghai-Tibet Plateau and the western edge of Sichuan Basin. In winter, it is located in the quiet wind area in the east of Qinghai-Tibet Plateau, with small wind and cloudy weather. In summer, the trough (vortex) located between the eastern China subtropical high center and the Iranian subtropical high center is easy to develop. Ya 'an City is located on the windward slope of the western margin of the basin, which is very beneficial to the precipitation in Ya 'an area. Especially when the subtropical ridge in eastern Sichuan is blocked, when the above system is affected, it is more conducive to the formation of heavy rain and heavy rain in Ya 'an area. Summer precipitation can last until early autumn.

By September and June, 65438+1October, the Pacific subtropical high weakened, and then the ground winter wind began to invade Sichuan and Guizhou, while the southwest monsoon in Yunnan-Guizhou Plateau was still strong. This southwest airflow appears on the surface winter wind, which increases the rainfall in Ya 'an area. Because Ya 'an has more precipitation in summer and autumn, cloudy days in winter and rainy days all year round, it is a famous "rainy city" in China. (