Why are the seasons like spring in Yunnan-Guizhou Plateau?

Yunnan-Guizhou Plateau belongs to subtropical humid area and subtropical monsoon climate (Xishuangbanna belongs to tropical monsoon climate). Although it is a plateau in topography, the climate is significantly different due to different altitude and atmospheric circulation conditions. Affected by the southwest monsoon, the Yunnan-Guizhou Plateau has formed the characteristics that water resources are dry in winter and wet in summer, and the dry and wet seasons are distinct, so the Yunnan-Guizhou Plateau has four seasons like spring.

First, the formation process

About 200 million years ago, Yunnan-Guizhou Plateau was a long-term submerged bay with deep, pure and vast limestone.

About 208 million years ago, in the Late Triassic of Mesozoic, the Indosinian movement broke out, the crustal uplift and depression appeared alternately, and the sediments continued to accumulate, squeezing from the east and north, so that the materials concentrated in one direction. Due to the influence of gravity balance, the crust gradually thickened.

Since the Cenozoic era, the ground has risen rapidly and the plateau has formed. Eocene, about 36-53 million years ago, Himalayan orogeny occurred and Yunnan-Guizhou Plateau rose again.

From Neogene to early Pleistocene, influenced by the Pacific plate and the Indian plate, Guizhou was in a relatively stable period and its landform was relatively flat. Since the Middle Pleistocene, influenced by the continuous uplift of the Qinghai-Tibet Plateau, the formation of the Yunnan-Guizhou Plateau has been promoted, forming a landscape pattern of high in the west and low in the east of Guizhou.

Second, the regional scope

Yunnan-Guizhou Plateau is located in the middle-low latitude transition zone on the east side of Qinghai-Tibet Plateau, which is roughly located between east longitude100 ~1and north latitude 22 ~ 30.

Its scope includes the south of Sichuan Basin, the east of Diancang Mountain-Lijiang-Ailao Mountain and the vast area of western Guangxi. In addition to most areas of Yunnan and Guizhou provinces, it also includes southwest Sichuan and west Guangxi, with a length of about 1 1,000 kilometers from east to west and a width of 400-800 kilometers from north to south, with a total area of about 500,000 square kilometers.

It borders the Qinghai-Tibet Plateau in the west, Sichuan Basin in the north, Hubei and Hunan provinces in the east and Indochina Peninsula in the south. It is the main part of China's southwest frontier, and it is also the only way for China to reach Southeast Asia and South Asia.

Extended data

Overview of resources

1, land resources

By the end of 2000, according to the detailed land use survey data, cultivated land13.254 million square kilometers, garden land 235,500 square kilometers, forest land 3324165,438 square kilometers, grassland 3,693,800 square kilometers, and the land utilization rate of residential industry160,000 square kilometers was 80.6%, which was higher than that of residential industry.

Among the land use types, woodland is dominant, followed by cultivated land, and the area of unused land and cultivated land is almost the same. The soils are mainly paddy soil, red soil and yellow soil. The contiguous grasslands are mainly concentrated in northeastern Yunnan, southern Guizhou, northern Guizhou and western marginal areas.

2. Water resources

According to the information in the water resources bulletin of Yunnan Province in 20 15, at the end of the year, the inflow of the Yangtze River basin, the Pearl River basin, the Yangtze River basin, the Pearl River basin and the nine plateau lakes in Yunnan Province was 78.29 billion cubic meters, 3.277 billion cubic meters, 1 137 billion cubic meters, 26.72 billion cubic meters and 29.29 billion cubic meters respectively. ?

According to the information in the water resources bulletin of Guizhou Province in 20 15, the total water resources in Guizhou Province are1kloc-0/53.72 million cubic meters, incoming water 1495438+09 million cubic meters, and outgoing water 125438+04 million cubic meters. The water quality of the river is within the assessed 7743.8km reach. The proportion of water quality meeting the second and third class standards of Environmental Quality Standard for Surface Water is 865438 0.4%.

3. Water resources

Yunnan-Guizhou Plateau is rich in hydropower resources, and it is the southern corridor and an important export destination for power transmission from west to east. According to the statistical data of China Hydropower Engineering Society in 2009, the annual hydropower generation of international rivers in Southwest China is 848.86 billion kWh, accounting for 14.3% of the whole country, and the developed hydropower resources are 209.868 billion kWh, accounting for 10.9% of the whole country. The water resources of Jinsha River in Yunnan account for 38.9% of the total water resources in the province.

Baidu Encyclopedia-Yunnan-Guizhou Plateau (Southwest Plateau of China)