What are the characteristics of Yunnan's overall topography and climate?

The relatively flat mountainous areas in Yunnan only account for 10% of the total area, and a large area of land is uneven and undulating, and it is a flat plateau in a certain range. In the longitudinal valley area of western Yunnan, Gaoligong Mountain is the top of the Irrawaddy River and Nujiang River watershed, with snow all year round, forming a strange and magnificent mountain glacier landform. Tiger Leaping Gorge in Jinsha River is one of the world-famous canyons, with a relative height difference of more than 3,000 meters from the mountains on both sides. The straight-line distance from the west swinging iron cable of Lancang River to the top of Kage peak of Meili Snow Mountain is about 12km, and the height difference actually reaches 4,760m m. In the narrow range of 10km, it presents a peculiar landscape of subtropical dry-hot valley and alpine ice and snow world, and the natural scenery is equivalent to the latitude from Guangdong to Heilongjiang. The whole province is divided into three steps, the first step is in Deqin and Shangri-La counties in northwest Yunnan, the second step is in the central Yunnan Plateau, and the third step is in the south, southeast and southwest, with an average drop of 6 meters per kilometer. Basins and plateaus are commonly known as "bazi" in southwest China.

There are seven climate types in Yunnan province, including north tropical zone, south subtropical zone, middle subtropical zone, north subtropical zone, warm temperate zone, middle temperate zone and plateau climate zone. [14] The climate in Yunnan has the characteristics of low latitude climate, monsoon climate and mountain plain climate. Its main performance is:

Regional differences and vertical changes of climate. The latitude of Yunnan is related to altitude. From the latitude point of view, its location is only equivalent to the geographical latitude from Leizhou Peninsula to Fujian, Jiangxi, Hunan and Guizhou. However, due to the high terrain in the north and low terrain in the south, the height difference between north and south reaches 6663.6m, which greatly aggravates the temperature difference caused by latitude factors in the whole province. This combination of high latitude and high altitude, low latitude and low altitude is consistent, that is, the increase of latitude in the horizontal direction coincides with the increase of altitude in the vertical direction. Except Jinsha River Valley and Yuanjiang River Valley, the annual average temperature rises from north to south, with an average temperature of about 5 ~ 24℃ and a temperature difference of about 19℃.

Due to the influence of topography and different weather systems, the zonal distribution law of temperature in the whole province often has special circumstances, and the phenomenon of "hot in the north and cool in the south" appears. Especially in the vertical distribution, due to the mountainous territory, the river bed is constantly eroded, resulting in high mountains and deep valleys. From the valley to the top of the mountain, the climate types are different due to the height rise. Generally speaking, the temperature will drop by about 0.6℃ every time the plateau rises 100 meters. ..