When is a good time to go to Hexi Corridor?

The best time for Hexi Corridor: Lanzhou lives inland and is in the transition zone between monsoon climate zone and non-monsoon climate zone. It belongs to a typical temperate semi-arid continental monsoon climate zone, with dry climate, abundant sunshine, long and cold winter and little rain and snow. Spring is fleeting, and the temperature changes greatly; Summer is short and the temperature is high, but there is no heat; The temperature drops quickly in autumn. The annual average temperature is 9.3; C. The annual temperature difference and the daily temperature difference are relatively large. The best tourist season is May-10.

Scope: Wushaoling in the east, Guyumen in the west, and Nanshan (Qilian Mountain and Altun Mountain) and Beishan (Mazongshan Mountain, Helishan Mountain and Longshou Mountain) in the north and south. It is about 900 kilometers long and several kilometers wide to nearly 100 kilometers. It is a long and narrow flat land, extending from northwest to southeast, and shaped like a corridor, which is called Gansu Corridor. Because it is located to the west of the Yellow River, it is also called Hexi Corridor. Geographically, it includes Lanzhou and Gansu's "Hexi four counties": Wuwei (formerly known as Liangzhou), Zhangye (Ganzhou), Jiuquan (Suzhou) and Dunhuang (Guazhou). Hexi Corridor has been the main throat of eastern China to the western regions in past dynasties. Since the Han and Tang Dynasties, it has become a part of the Silk Road. /kloc-gradually declined after 0/5th century. At present, it is also the main road connecting East China and Xinjiang, and it is an important frontier in the northwest region. The geology, geomorphology and water system of Hexi Corridor belong to the marginal depression zone of Qilian Mountain geosyncline. During the Himalayan movement, Qilian Mountain rose greatly, and the corridor received a lot of alluvial and alluvial materials since Cenozoic. From south to north, the slope belt at the northern foot of Nanshan, alluvial belt, alluvial belt and the slope belt at the southern foot of Beishan appear in turn. The corridor is flat, with an altitude of about 1500m. The alluvial plain along the river forms large oases such as Wuwei, Zhangye and Jiuquan. The rest of the vast areas are dominated by wind erosion and dry erosion, and Gobi and desert are widely distributed, especially in the west of Jiayuguan, where the Gobi area is vast and the oasis area is smaller. Around the mountains in Hexi Corridor, the materials transported by mountains and rivers are piled up in front of the mountains, forming adjacent inclined plains in front of the mountains. There are also alluvial plains in the lower reaches of larger rivers. These areas, with flat terrain, fertile soil, good irrigation conditions and easy development and utilization, are the main distribution areas of oasis in Hexi Corridor. Hexi Corridor has a dry climate, and the annual precipitation in many places is less than 200mm. However, Qilian Mountain is rich in ice, snow and meltwater, and irrigation agriculture is developed.

The corridor is divided into Shiyang River, Heihe River and Shule River, which are bounded by Heishan, Kuantai Mountain and Dahuangshan. They all originate from Qilian Mountain and are replenished by meltwater and rainwater, and generally freeze in winter. After the rivers come out of the mountains, most of them infiltrate into the Gobi desert to form undercurrents, or are irrigated by oases, and only the downstream of larger rivers is injected into the terminal lake. ① Shiyang River system. Located in the east of the corridor, the piedmont area of Qilian Mountain in the south is loess ridge and alluvial fan at the foot of the mountain, and sandy desert, denuded rocky mountain and residual hill in the north. Tengger desert in the east and Wuwei basin in the middle. ② Heihe River system. Some things are between Dahuangshan and Jiayuguan. Most of them are gravel deserts and sandy deserts, and there are many sand dunes in the northern margin. Only Zhangye, Linze, Gaotai and Jiuquan form a large area oasis, which is an important agricultural area in Hexi. Since ancient times, it has been called "Golden Zhangye, Silver Wuwei". ③ Shule River system. Located at the western end of the corridor. In the south, there are high mountains east of Altun Mountain and west of Qilian Mountain, as well as a series of exposed low rocky mountains (namely Sanwei Mountain, Duanshan Mountain, Mushroom Mountain, etc.). ) piedmont. There is a horsehair mountain in the north. The central corridor is an oasis in the middle reaches of Shule River and Dunhuang oasis in the lower reaches of Danghe River, and the lower reaches of Shule River are saline-alkali beaches. Outside the oasis is a wide Gobi with sand dunes in the middle.

climate

Cold wave weather often forms in Hexi Corridor in winter and spring. The main source of summer precipitation is the summer monsoon invading this area. The climate is dry, hot and cold change dramatically, windy and sandy. From east to west, the annual precipitation is decreasing and the dryness is increasing. For example, the annual precipitation in Wuwei 158.4 mm, Dunhuang 36.8mm；; The dryness of Jiuquan is 4 ~ 8 in the east and 8 ~ 24 in the west. Precipitation changes greatly every year. Precipitation in summer accounts for 50-60% of the annual total, spring15-25%, autumn10-25% and winter 3-16%. There are fewer clouds and more sunshine hours, 3000 hours in most areas and 3336 hours in Dunhuang in the west. The annual average temperature is 5.8 ~ 9.3℃, but the absolute maximum temperature can reach 42.8℃ and the absolute minimum temperature is -29.3℃, with a difference of more than 72.65438 0℃. The average temperature difference between day and night is about 65438 05℃, and there are four seasons in a day. The number of sandstorm days in Minqin is more than 50 days, while the number of gale days above magnitude 8 in Anxi is 80 days a year, which is called "wind warehouse". The wind in the corridor is changeable. Wuwei and Minqin areas are dominated by northwest wind; Yumen, Anxi, Dunhuang and other places west of Jiayuguan are dominated by northeast wind and east wind.

land

The cultivated land in Hexi Corridor is mainly distributed in the piedmont plain. The upper part of alluvial fan is mainly composed of gravel mixed with coarse sand, which is rarely used at present. The middle and lower parts of alluvial fans are mainly sandy soil, mostly cultivated land. The alluvial plain has fine soil, mainly composed of clayey silt and loam, and is also the main area for farming. Under the condition of long-term cultivation and irrigation, a soil layer with a thickness of 1 meter, high organic matter content and high soil fertility has been formed, which provides superior conditions for developing agriculture. Brown desert soil is located in the west of the corridor, gray brown desert soil is in the middle, gray desert soil, light brown calcium soil and gray calcium soil are in the east of the corridor, and light brown calcium soil is distributed in the grassland desert area near the southern edge of the desert. Calcareous soil is distributed in loess hills, alluvial fan terraces and plain oases in front of Qilian Mountain. The western end of the gray-brown desert soil belt is dominated by gypsum gray-brown desert soil, while the eastern end is dominated by ordinary gray-brown desert soil and loose sandy primary gray-brown desert soil, and the northeast primary gray-brown desert soil and loose sandy soil like gray-brown desert soil occupy a significant position. Saline soil is widely distributed in low-lying areas, and its area gradually expands from east to west. The distribution area of meadow soil decreases from east to west. Zonal vegetation is mainly composed of super-xerophytic shrubs, semi-shrub deserts and super-xerophytic semi-arbor deserts. The desert vegetation in the east has obvious grassland characteristics, forming a unique grassland desert type, such as salsola, Cynanchum komarovii and so on. In addition to common desert species such as red sand, beer flowers and plants, and salt claws with sharp leaves, there are different levels of grassland components, mainly including Stipa arenaria, Stipa breviflora, Stipa Gobi, Cryptospermum apetalum, Stipa tenuifolia, Allium mongolicum and Allium mongolicum. Gravel Gobi and dry denuded stony residual hills are widely distributed in the west, and the ecological environment is severe. There are typical desert vegetation in the gravel Gobi, such as red sand, ephedra, bubble thorn, Mubawang, naked fruit trees and other community types. Mobile dunes include Calligonum Calligonum, seed height, sand rice and sand mustard. Fixed dunes often have Tamarix ramosissima, Nitraria dentata, Nitraria tangutorum and so on. There are a few Populus euphratica forests and Elaeagnus angustifolia forests in the middle and lower reaches of Shule River and Beida River. In the lowlands of lake basin, there are salt claws with thin leaves, salt claws with salt claws and salt desert with salt grass in the hidden habitat of salinization phreatic water recharge. There are saline meadows composed of reed, Achnatherum splendens, licorice, camel thorn, wild silkworm, Sophora alopecuroides, iris and Euphorbia humifusa. In order to prevent sandstorms and dry-hot winds, Populus davidiana, Populus cathayensis, Populus Xinjiang and Elaeagnus angustifolia were used to build windbreaks in oasis areas, and the effect was remarkable. The irrigated agricultural area in Hexi Corridor has a long history and is one of the important agricultural areas in Gansu Province. It is the most important commodity grain base and concentrated production area of cash crops in northwest China. It provides more than 2/3 of the province's commodity grain, almost all cotton, 9/ 10 sugar beet, more than 2/5 of oil, fruits and vegetables. The flat oasis area mainly grows spring wheat, millet, millet, corn and a small amount of rice, sorghum and potatoes. Oil crops are mainly flax. Melons include watermelon, white melon, etc. Fruit trees are mainly jujube, pear and apple. The piedmont area is dominated by summer miscellaneous grains, mainly planting highland barley, rye, broad bean, pea, potato and rape. Hexi has developed animal husbandry, such as Shandan Maying Beach, which has been a famous military horse farm since ancient times.

nation

Ethnic groups are Han, Mongolian, Tibetan, Yugur, Kazak, Hui and Manchu. Mainly Han nationality, mainly engaged in agriculture in oasis areas. Tibetans, Yugurs, Kazakhs and Mongolians are engaged in animal husbandry. Mineral resources include Yumen petroleum, Shandan coal, Jinchang nickel and other metals.