A brief introduction to Yunnan’s topography, climate, folk customs, rivers, lakes, and transportation

Geographical overview of Yunnan

1. Location and area

Yunnan, referred to as Dian, is located in the southwest border of China, at 21°8'32" - 29° north latitude 15'8", between 97°31'39" and 106°11'47" east longitude, the Tropic of Cancer runs through the southern part of the province. The province's maximum horizontal distance from east to west is 864.9 kilometers, and the maximum vertical distance from north to south is 990 kilometers. The total area is 394,000 square kilometers, accounting for 4.1% of the country's total area, ranking 8th in the country.

Yunnan Province borders Myanmar to the west and southwest, Vietnam and Laos to the south, Guangxi Zhuang Autonomous Region and Guizhou Province to the east, Sichuan Province to the north, and Tibet Autonomous Region to the northwest. The national border is 4,061 kilometers long. It is one of the provinces and regions with the most neighboring countries and the longest border in my country. Yunnan has 8 border prefectures and 26 border counties. It has opened 11 national-level ports, 9 provincial-level ports and nearly 100 border passages. It has convenient exchanges with neighboring countries and even other countries and regions in Southeast Asia and South Asia. It is China's communication hub. The main land passage in Southeast Asia and South Asia has extremely favorable opening conditions along the border.

2. Population, ethnic groups and administrative divisions

At the end of 2001, the total population of Yunnan Province was 42.874 million. In addition to the Han people, there are 25 ethnic minority groups with a population of more than 50 million, 15 of which are unique to Yunnan. The ethnic minority population accounts for 1/3 of the total population of the province. Yunnan not only has a large population of ethnic minorities, but also has the largest variety of ethnic minorities in the country. In addition, Yunnan is also the province with the largest number of cross-border ethnic groups in the country. Among the 25 ethnic minorities, 13 ethnic groups span the borders of China-Vietnam, China-Laos, and China-Myanmar. They are distributed in the vast areas of northern Vietnam, northern Laos, and northern Myanmar. Some ethnic groups also extend to Thailand, Cambodia, and India. There are many cross-border ethnic groups, which adds a kind of kinship with the people of neighboring countries, which is very beneficial to Yunnan's expansion of opening up to the outside world.

Yunnan Province has jurisdiction over 16 prefectures, states, and cities, including 8 ethnic autonomous prefectures, 5 provincial cities, and 3 regions. There are 128 county-level administrative units, including 29 ethnic autonomous counties. . Kunming, the provincial capital, and other major cities include Yuxi, Qujing, Gejiu, Dali, Chuxiong, Baoshan, Lijiang, Simao, Jinghong, Ruili, etc.

3. Topography and landforms

The terrain of Yunnan is high in the northwest and low in the southeast, with extremely high altitude differences. The highest point is Kagebo Peak, the main peak of Meili Snow Mountain in Deqin County at the junction of Yunnan and Tibet, with an altitude of 6740 meters; the lowest point is at the intersection of Nanxi River and Yuanjiang River in Hekou County on the border with Vietnam, with an altitude of only 76.4 meters. The straight-line distance between the two places is 900 kilometers, and the height difference is more than 6,000 meters.

Yunnan belongs to the southern extension of the Qinghai-Tibet Plateau. The terrain is bounded by the Yuanjiang Valley and the wide valley in the southern section of the Yunling Mountains, and is divided into east and west parts. To the east are the East Yunnan and Central Yunnan Plateaus, with undulating topography, with an average altitude of about 2,000 meters. They are characterized by gently undulating low mountains and rounded hills, and various types of karst terrain are developed. The west is the longitudinal valley area of ??the Hengduan Mountains, with alternating high mountains and deep valleys, a large relative height difference, and steep terrain. The altitude in the southwest is generally 1500-2200 meters, and in the northwest is generally 3000-4000 meters. In the southwest, the terrain gradually becomes gentle only in the border areas. The valleys here are open and the altitude is generally between 800 and 1,000 meters. In some areas, the altitude drops below 500 meters, forming the main tropical and subtropical areas of Yunnan.

Yunnan’s landform has five characteristics:

First, the plateau is undulating. Relatively gentle mountainous areas only account for 10% of the total area. A large area of ??land has varying heights, undulating vertically and horizontally, and there is a gentle plateau in a certain range.

The second is alternating mountains and valleys. Northwest Yunnan has the famous West Yunnan Longitudinal Valley area. Gaoligong Mountain is the watershed between the Irrawaddy River and the Nu River, Nu Mountain is the watershed between the Nu River and the Lancang River, and Yunling is the watershed between the Lancang River and the Jinsha River. Each river cuts down strongly, forming an extremely majestic landform. form. The Nujiang River Gorge, the Lancang River Gorge and the Jinsha River Gorge are majestic. The relative height difference between the mountains and the canyon exceeds 1,000 meters. Among them, the Nujiang River Gorge is more than 300 kilometers long from north to south and is known as the "Grand Canyon of the East". On the tops of mountains above 5,000 meters, there is often permanent snow, forming strange and majestic mountain glacier landforms. The "Tiger Leaping Stream" canyon in the Jinsha River has a relative height difference of more than 3,000 meters with the mountains on both sides. It is one of the world's famous canyons. The straight-line distance from the Xidang Iron Cable on the Lancang River to the Kagebo Peak of the Meili Snow Mountain is about 12 kilometers, and the height difference reaches 4,760 meters. Within a narrow range of more than 10 kilometers, it presents a strange landscape of subtropical dry hot valleys and alpine ice and snow worlds. , the natural scenery is equivalent to the latitude spanned from Guangdong to Heilongjiang, which is rare in the country.

Third, the terrain is gradually descending. The province is divided into three echelons. The area around Deqin and Shangri-La counties in northwest Yunnan is the first echelon, the Central Yunnan Plateau is the second echelon, and the south, southeast and southwest are the third echelon, with an average gradient of 6 meters per kilometer.

Fourth, fault basins are scattered. Basins and plateaus are commonly known as "Bazi" in the southwestern region. Such landforms can be seen everywhere in Yunnan.

Yunnan has 1,442 large and small dams with an area of ??1 square kilometers, and 49 dams with an area of ??more than 100 square kilometers. The largest dam is Luliang Bazi, followed by Kunming Bazi.

Fifth, there are rivers and lakes. Yunnan not only has many mountains, but also many rivers and lakes, which are characterized by crisscrossing mountains, intertwined water systems, and scattered lakes. The main mountain systems include Wumeng Mountain, Hengduan Mountain, Ailao Mountain, and Wuliang Mountain. There are more than 600 large and small rivers in Yunnan, which belong to six major river systems: the Irrawaddy River, the Nu River, the Lancang River, the Jinsha River (Yangtze River), the Yuanjiang River (Red River) and the Nanpan River (Pearl River). These rivers flow into the South China Sea and the Indian Ocean respectively. Most of them have the characteristics of large drops and fast currents, and are extremely rich in water energy resources. Among them, the Irrawaddy River, Nu River, Lancang River and Yuanjiang River are international rivers. There are more than 40 plateau lakes in Yunnan. The more famous lakes include Dianchi Lake, Erhai Lake, Fuxian Lake, Xingyun Lake, Yangzonghai, Chenghai, Lugu Lake, etc. The natural lakes are like pearls dotted among the mountains, looking particularly beautiful and crystal clear.

IV. Climate types and characteristics

Yunnan is located on a low-latitude plateau. It is controlled by the dry continental monsoon in winter and the humid ocean monsoon prevails in summer. The climate is mainly a low-latitude mountain monsoon climate. The province has rich and diverse climate types, including seven climate types: northern tropical zone, southern subtropical zone, central subtropical zone, northern subtropical zone, southern temperate zone, mid-temperate zone and plateau climate zone. Due to complex terrain and large vertical height differences, the three-dimensional climate characteristics are remarkable. The most prominent features are small annual temperature difference and large daily temperature difference; abundant precipitation, distinct dry and wet conditions and uneven distribution; and obvious differences in vertical climate changes. In summer, there are many cloudy and rainy days, the sun is blocked by clouds, and the temperature is not high enough. The hottest days are generally between 19 and 22 degrees Celsius. In winter, controlled by dry and warm currents, there are many sunny days, sufficient sunshine, and high temperatures. The coldest monthly average temperature is above 6-8 degrees Celsius. The annual temperature difference is generally only 10-12 degrees Celsius, but the temperature is lower on rainy days. Judging from the temperature changes throughout the day, it is cooler in the morning and evening and hotter at noon. Especially in winter and spring, the daily temperature difference can reach 12-20 degrees Celsius. The amount of water in most areas of the province is above 1,000 mm, but the precipitation is extremely unevenly distributed seasonally and geographically. 85% of the rainfall is concentrated in the rainy season from May to October, especially June, July and August. The dry season is from November to April, with precipitation accounting for only 15% of the year. The regional distribution of precipitation is very uneven. The annual precipitation in the most places can reach 2200-2700 mm, and the annual precipitation in the least places is only 580 mm. As the increase in horizontal latitude coincides with the increase in altitude, the province exhibits a three-zone climate of cold, warm and hot at 8 latitudes. Generally speaking, for every 100 meters of altitude increase, the temperature decreases by about 0.6°C. Therefore, "one mountain has four seasons, and ten miles have different weather" has become a vivid portrayal of Yunnan's climate diversity.

Yunnan has a long frost-free period. The southern border is frost-free all year round. Wenshan, Mengzi, Simao, Lincang, Dehong and other places in the south have a frost-free period of 300-330 days. Kunming, Yuxi, Chuxiong and other places in the central part have a frost-free period of 250 days. The colder Zhaotong and Lijiang also have a frost-free period of 300-330 days. Up to 210-220 days. In addition, Yunnan has good lighting conditions, with 90-150 kilocalories per square centimeter per year, second only to Tibet, Qinghai, Inner Mongolia and other provinces.

The above-mentioned climate characteristics of Yunnan are suitable for the growth of a variety of organisms, laying a good foundation for the province's innovative agriculture, development of biological resources and production of specialty products.