Why is there much precipitation in Sichuan Basin?

The terrain of Sichuan basin is closed, and the temperature in winter is higher than that in other areas of the same latitude because the North Qinling Mountains block the cold air. The annual precipitation in Sichuan Basin is 65,438+0,000 ~ 65,438+0,300 mm, and the precipitation in the mountainous areas around the basin is very rich. For example, the annual precipitation in the western mountainous area between Leshan and Ya 'an is 1.500 ~ 1.800mm, which is a prominent rainy area in China and is called "West China Rain Curtain".

However, winter drought, spring drought, summer waterlogging and autumn Mao Mao rain are unevenly distributed in the year, and 70 ~ 75% of the rainfall is concentrated in 6 ~ 10. The maximum daily precipitation can reach 300 ~ 500mm. "Night rain" has been famous since ancient times, and it accounts for more than 60 ~ 70% of the total rainfall. The fog in the basin is big and wet, and the clouds are low and cloudy.

Emei Mountain and Jinfo Mountain are one of the regions with the most foggy days in China, and the annual relative humidity is also the highest in China. The annual sunshine in the basin is only 900 ~ 1300 hours, and the annual solar radiation is 370 ~ 420 KJ/cm2, both of which are the lowest in the country, so it is called "the tree spring barks at the sun".

Extended data:

Climate type:

The temperature in the basin is high in the southeast and low in the northwest, with high bottom and low edge. The annual average temperature is 16 ~ 18℃. The active accumulated temperature above 10℃ is 4500 ~ 6000℃ and lasts for 8 ~ 9 months, belonging to the middle subtropical zone. The accumulated temperature in the southeast Yangtze River basin exceeds 6000℃, which is equivalent to the tropical climate of South Asia south of Nanling in China. The temperature in the basin is high in the east and low in the west, high in the south and low in the north, high in the bottom and low in the edge, and the isotherm distribution is concentric.

The temperature in the mountainous area on the edge of the basin has vertical distribution characteristics. The elevation of Emei Mountain and Jinfo Mountain rises by 100 m, and the temperature drops by 0.55℃ and 0.6 1℃ respectively. The average annual temperature at the top of Mount Emei is only 3℃, and the active accumulated temperature above 10℃ is 586℃, which is equivalent to cold temperate zone and sub-cold zone in climate.

Baidu Encyclopedia-Sichuan Basin