Climatic characteristics of 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 average temperature in Leng Yue is 3 ~ 5℃ in the north and 5~8℃ in the south, which is 1 ~ 4℃ higher than that in Shanghai, Hubei, Anhui and Guizhou in the south. The extreme minimum temperature in the north of the basin is -8 ~-5℃, and the extreme minimum temperature in the south is -5 ~-2℃. Frost and snow are scarce, and the frost-free period is 280 ~ 350 days throughout the year. In winter, there is constant frost and snow in Wuhan at the same latitude, and Changning, whose basin is located in the Yangtze River basin, is frost-free all the year round.

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 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.

Extended data:

Characteristics of Sichuan Basin:

1, landform features

The Sichuan Basin can be clearly divided into two parts: marginal mountain and basin bottom, with an area of about 654.38+10,000 square kilometers and160,000 square kilometers respectively. There are many middle and low mountains in the marginal mountainous areas. The elements of the landscape are obviously transitional, such as the composition of animals and plants permeating the components of Central China, Southwest China, Qinghai-Tibet Plateau and North China respectively. Generally, there are 2 ~ 5 vertical natural zones from bottom to top in marginal mountainous areas.

2. Morphological characteristics

The outline of Sichuan basin is generally approximate to a rectangle, shaped like an envelope and inclined to the right on the Asian continent, so it is called an envelope basin by geographers. Yunyang in the east (near Wanzhou), Xuyong in the south (near Zunyi), Ya 'an in the west, and Guangyuan in the north of the envelope basin.

3. Topographic elements

Daba Mountain, Micang Mountain and Longmen Mountain in the north, Qionglai Mountain and Daliangshan Mountain on the edge of Qinghai-Tibet Plateau in the west, Dalou Mountain in the south and Wushan Mountain in the east, surrounded by mountains and plateaus with an altitude of 2000-3000 meters. Sichuan basin is a typical basin in structure and human landform. It has been a large depression area with relatively stable crust since Sinian.

4. Geological characteristics

Sichuan basin belongs to Sichuan depression of Yangtze paraplatform. Paleozoic was relatively uplifted, lacking Devonian and Carboniferous. Indosinian movement transformed into a large depression, and fold uplift occurred in the late Yanshan period, especially after Himalayan movement. The basin pattern is mainly controlled by NE-SW and NW structural lines, forming a typical rhombic basin. Sichuan Guangyuan, Sichuan Ya 'an and Sichuan Xuyong are the four vertices of the diamond, which are slightly longer on the east and west sides, 380-430 km, and slightly shorter on the north and south sides, 365,438+00-330 km.

Baidu Encyclopedia-Sichuan Basin