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In the hinterland of the motherland, at the intersection of the western part of Qinba Mountain and the eastern edge of Qinghai-Tibet Plateau, there is an ancient and magical place. Here are beautiful mountains and rivers, warm climate, dense forests, rich resources, beautiful people and outstanding people. This is the key to Gansu, Shaanxi and Sichuan provinces. Known as "the key of Qin Long is the throat of Bashu", it is also known as "Longshang Jiangnan" in Longnan City, Gansu Province.
Longnan City is located in the south of Gansu Province, bordering Shaanxi in the east, Sichuan in the south, Gannan Tibetan Autonomous Prefecture in the west and Dingxi and Tianshui in the north. Its geographical coordinates are1041'-10635' and 32 38'-34 365433 north latitude. It is 22 1km long from east to west and 220km wide from north to south, with a total area of 27,900km2. The city has jurisdiction over 9 counties including Wudu, Dangchang, Wenxian, Chengxian, Kangxian, Huixian, Xihe, Lixian and Liangdang, 242 townships, 3,423 villagers' committees, with 540,000 households and 2.5 million people. There are 2/kloc-0 ethnic groups such as Han, Hui and Tibetan, 7 ethnic townships, and the population of ethnic minorities is more than 50,000. The municipal government is stationed in Chengguan Town, Wudu District.
Various landforms and landforms
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Longnan is located in the mountainous area of Longnan, where the east-west fold belt of West Qinling develops, and is in the transitional zone of stepped terrain in China. It reaches Gannan Plateau in the west, Loess Plateau in central Gansu in the north, Sichuan Basin in the south and Qinling and Hanzhong Basin in Shaanxi in the east. The terrain of this city is high in the northwest and low in the southeast. Mountains, deep valleys, hills and basins in the territory are distributed and staggered in turn, forming a unique and intricate magnificent landscape. Xili Mountain in the north presents a loess landform with low mountains and wide valleys, with an altitude of 1800 meters. Huicheng Basin in the east is located between the northern Qinling Mountains and the southern Qinling Mountains, with a length of more than 100 kilometers and a width of several tens of kilometers, with a hilly and wide valley topography and an altitude of about 1000 meters. There are mountain canyons in the southwest, and the mountains and deep valleys are staggered, with remarkable contrast. "The head is steep and the ears are rough", and the relative height difference exceeds 1000 meters. From northwest to southeast, from high mountains such as Dalaliang and Min 'e Mountain (elevation 3552m) to low mountains such as Duantou Mountain (elevation 1804m) and Jinzi Mountain (elevation 1824m), the mountains overlap. In the meantime, the valley is deep and narrow, winding and deep, with many rapids, rapids and waterfalls. The high river banks and steep cliffs in the canyon stand like a wall. Many narrow alluvial plains appear intermittently beside the valley, among which Wudu Plain is nearly 50 kilometers long and 1 km wide. Surrounding peaks: Dalaliang and Min 'e Mountains in the Yangtze River and Yellow River watershed in the north, Toumaju Mountain at the junction of Shaanxi and Gansu in the east, Congdi Mountain adjacent to Gannan in the west and Motianling Mountain at the junction of Gansu and Sichuan in the south. Xiong Huang Mountain, the highest peak, is 4187m above sea level, located in Tunzhai Township, northwest of wen county. Guanzigou, the lowest point, is 550 meters above sea level, located in Zhongmiao Township, southeast of Wenxian County, which is also the lowest altitude in Gansu Province.
Dense rivers and streams.
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Longnan is the only Yangtze River valley in Gansu. There are many mountains and waters in the territory, and the water is as high as the mountains. Among the mountains, streams are undulating everywhere and waterfalls are rushing. All rivers in the city belong to Jialing River system, with 48 first-class tributaries such as Bailong River and Xihanshui, with a total length of 1.297 km. There are 75/kloc-0 secondary tributaries such as Baishui River and Minjiang River, with a total length of 4,756 kilometers; Third-class tributary 165 1 article, with a total length of 4313 km; There are 13 12 tributaries with a total length of 3428 kilometers. Hundreds of rivers compete for flow, the river network is vertical and horizontal, and the river density reaches 0.5 per square kilometer. Main rivers: The main stream of Jialing River flows through Liangdang and the southeast of Huixian, with a domestic flow of 86.2 kilometers, an annual runoff of 2.2 billion cubic meters and a drainage area of 2,556 square kilometers. The West Han River, a tributary of the upper reaches of Jialing River, flows through Lixian, Xihe, Chengxian and Kangxian, with a domestic flow of 205.6 kilometers, an annual runoff of 65.438+67 billion cubic meters and a drainage area of 9,569 square kilometers. Bailong River, the largest tributary in the upper reaches of Jialing River, flows through Dangchang, Wudu and Wenxian counties, with a domestic flow of 229.5 kilometers, an annual runoff of 9.38 billion cubic meters and a drainage area of 65.438+0.32 million square kilometers. Baishui River, a secondary tributary of Jialing River, enters at Shijiba Township, Wen County, and flows into Bailong River at Jiekouba, Lei Yu Township, with a domestic flow of 107.3 km, an annual runoff of 3.43 billion cubic meters and a drainage area of 3,040 square kilometers. Bailong River, with Qinling Mountains and Huaihe River, is located between 33 and 34 north latitude and belongs to the 0℃ isotherm passing zone of 1. The river south of this line is not frozen, so it is the natural dividing line between the north and south of China and Qinling Mountains and Huaihe River.
Three-dimensional distribution of diverse climate
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Longnan belongs to the East Asian monsoon climate zone. Due to the special geographical location and the influence of mountains, the climate in the region is complex and diverse, with unique distribution, and the horizontal and vertical zoning are very obvious, forming a strange landscape of "one mountain with four seasons and ten miles of different days".
First, the temperature difference between north and south is large. From southeast to northwest, from subtropical humid climate to warm temperate humid climate, temperate semi-humid climate and cold and humid climate, the annual average temperature is 5℃- 15℃, sunshine hours 1700-2000 hours, active accumulated temperature is 2600-4600℃, and annual precipitation is 450-65438+. Wudu, south of Wenxian County, southeast valley of Kangxian County ....