The evolution of Anhui's culture and administrative divisions and the physical geography characteristics, and the physical geography characteristics of Anhui's cultural areas.

The evolution of Anhui's culture and administrative divisions and the physical geography characteristics, and the physical geography characteristics of Anhui's cultural areas.

Anhui's landform consists of plains, plateaus, hills and mountains. Dabie Mountain is located in the west, Huangshan Mountain and Jiuhua Mountain are located in the south edge, and the central hills span the whole country. The Yangtze River and Huaihe River cross the country from south to north, naturally dividing Anhui into five natural regions, namely Huaibei Plain, Jianghuai Hilly Area, West Mountain Area of Anhui, Plain Area along the Yangtze River and South Anhui.

Huaibei Plain is located in the northernmost part of Anhui, including Huaibei, Fuyang, Suxian and other cities. This is a part of the Great Plain of North China. In addition to scattered hills or isolated hills in the north of He Sui and along the Huaihe River, the ground is a plain deposited by Huaihe River, Yellow River and its tributaries. Huaibei plain can be further divided into three parts: Hejian plain, Huangpan plain and floodplain along Huaihe River. Hejian Plain is the main part of Huaibei Plain, including Linquan, Yang Guo, Suxian, Lingbi and the south of Sixian County. There are many semi-closed depressions along the Huaihe River beach, so there is not much precipitation in this area, but it is easy to form floods. The flood plain of the Yellow River was formed by many times of southward invasion and deposition of the Yellow River in modern geological history, mainly distributed in the northern Hejian Plain and along the north-south main rivers. The Yellow River is called "big flat and small uneven" because of its changeable water flow, unequal sediment thickness and uneven ground. Among them, high beaches, crevasse fans, sloping fields and depressions crisscross, and the soil is easy to salinize. The beaches along the Huaihe River are mainly distributed in the downstream coastal areas of the Huaihe River and its main tributaries, with low terrain and often flooded in flood season.

Jianghuai hilly region is located in the middle of Anhui, bounded by Huaibei Plain in the north and separated from the hilly plain along the river in the west of Anhui by Dabaifan-Shiqiao-Gangji-Ji Huang-Chenyan line in the south, including Huainan, Bengbu, Lu 'an, Hefei, Chuzhou and Chaohu. The ground is mainly composed of hills and terraces, with undulating hills and mixed valleys. This area can be divided into four parts according to the topographic features: Huainan depression, mainly distributed in six counties along the Huaihe River, is deposited by the main stream of the Huaihe River, with a wide plain, but due to erosion, the ground often fluctuates, forming many lake depressions, which is a waterlogging-prone area in the middle reaches of the Huaihe River; Stone Pi River hilly area, distributed in Lu 'an hilly area and Feidong, Changfeng and Hefei; In the hilly areas of (Yang) and Jiashan (Mountain), there are not only large hills and hills, but also many large-scale low mountains. The hilly land has thick soil layer, less surface and groundwater, and is easily affected by drought. The southern hilly area is distributed in Chaohu, Chuxian, Anqing and Shucheng. In addition, there are lakes in this area, such as East, West, Wabu and Nvshan. The lake is flat, forming a vast lake and swamp plain, in which large polder fields are scattered. This area is one of the main agricultural areas in Anhui, but it is prone to floods.

Xishan District of Anhui Province is the birthplace and watershed of some tributaries of the Yangtze River and Huaihe River in the west, bordering Henan and Hubei provinces in the west, the Jianghuai hills and platforms in the northeast, and the plain along the Yangtze River in the southeast by Susong-Taihu-Buried Hill-Tongcheng Line, including all or part of Jinzhai, Huoshan, Lu 'an, Shucheng, Yuexi, Tongcheng, Buried Hill, Taihu Lake and Susong counties, across Henan. With a slope of more than 25 degrees, Zhongshan, which is more than 1000 meters, occupies a considerable area, with steep mountains and deep canyons, but there are also some places dominated by hills, with large terraces and valleys.

The plain along the Yangtze River is located on both sides of the Yangtze River in the south-central Anhui, connected to the hills and platforms of Jianghuai Mountain in the north, and separated from the hills and hills of southern Anhui by Xiangyu-Guichi-Tongling-Fanchang-Wan Zhi-Xuanzhou-langxi in the south, including Anqing, Chaohu, Hefei, Chizhou, Tongling, Wuhu, Xuancheng and Maanshan, which is caused by the subsidence of geological structures and the siltation of the Yangtze River and its tributaries. It can be divided into three parts: the plain area above Tongling, with Anqing as the center, is often called Anqing Valley because of the narrow plain and the mixed hills, hills and lakes; Below Tongling, the plain on both sides of the river with Wuhu as the center is a typical water network plain with low terrain, dense water network, contiguous polder fields and criss-crossing buildings. The plain around Chaohu Lake has obvious basin characteristics, with wide and flat terrain and staggered polder fields.

The mountainous area in southern Anhui is located at the southernmost tip of Anhui, bordering the plain along the Yangtze River in the north, Jiangsu and Zhejiang in the southeast and Jiangxi in the southwest, including all Huangshan City and parts of Chizhou, Tongling, Wuhu and Xuancheng. The ground is dominated by mountains and hills, mostly northeast-southwest trend. Valley plains and basins are distributed among mountains. The widest river basins are Qingyi River Basin and Shuiyangjiang River Basin, and the largest is Xiuning-Tunxi River Basin.

Anhui has magnificent mountains and rivers, and the mountains are mainly distributed in western and southern Anhui. Huoshan Mountain in western Anhui is located in the hinterland of Dabie Mountain. The mountain is high and steep, with an altitude of 1000 meters. Baimajian, the main peak, is as high as1.774m.. It is majestic and steep, with many steep cliffs and steep rocks. The vertical distribution of vegetation is remarkable. From bottom to top, it is evergreen deciduous broad-leaved mixed forest, deciduous broad-leaved forest, Huangshan pine forest, alpine dwarf forest and shrub. The famous peaks of Huoshan are Yunfeng, Datong, Mingshan Xiaozhai, Huangyangling, Wangsishan and Shuangjian, all of which are 1000 meters long. Yuexi county is named after the confluence of many branches. The height of the main peak is also 172 1 m, with steep mountains and dense plants. The main peak of Jiangjun Mountain in Taihu County also reaches 1 109 meters. The ridge is uneven and there are many strange peaks and rocks. The mountainous areas in southern Anhui are mainly composed of Tianmu Mountain, Huangshan Mountain and Jiuhua Mountain. Of course, the most famous mountain is Huangshan, and the highest point, Lotus Peak, is 1873 meters above sea level. Baiji Mountain, located at the junction of Anhui, Zhejiang and Jiangxi provinces, is an extension of Tianmu Mountain in the southwest. The elevation of the ship peak is 148 1 m, which is steep and steep. The main peak of Dahongling in Qimen County is 1 126 meters above sea level, with wide back and gentle slope. The highest peak of Xianyuling, which spans Dongzhi, Shitai, Guichi and other cities and counties, is1375m above sea level. The ridge is broad and gentle, with steep south slope and gentle north slope.

Rivers in Anhui belong to Huaihe River, Yangtze River and Xin 'anjiang River. The Huaihe River originated in Tongbai Mountain, Henan Province, and flowed eastward to Honghekou, the border river between Henan and Anhui provinces, and then went down to Shantou to enter Hongze Lake in Jiangsu Province. It belongs to the middle reaches in Anhui Province, with a total length of 37 1 km. The main stream of Huaihe River is the geographical dividing line between north and south of China, and also the southern boundary of frozen rivers in China. It has a freezing period of about half a month every year, and the rivers south of it are not frozen. There are many tributaries of Huaihe River, and the north and south banks are asymmetrical. From west to east, there are Guhe River, Herun River, Heying River, Xifei River, Cihe River, Guohe River, Huihe River, Tuohe River, Tonghe River and Tanghe River. Generally, the water flow is long and gentle, which is easy to deposit sediment and discharge poorly. From west to east, there are Shishe River, Jihe River, Fenghe River, Laihe River, Donghe River, Heyao River, Haohe River, Chihe River and Xiaoxi River on the south bank, with short overall flow direction and rapid water flow. The Yangtze River flows into Jiangsu from Jiujiang, Jiangxi, to Wujiang, and belongs to the downstream in Anhui, with a total length of 40 1 km. The tributaries of the Yangtze River flow into Huayang River, Anhui River, Yuxi River, Caizi Lake System, SaiBrina Lake System, Chaohu Lake System and Chuhe River on the north bank, and into Longquan River, Changhe River, Huangpen River, Qiupu River, Jiuhua River, Bronze River, Qingyi River and Shuiyangjiang River on the south bank. There are many lakes on both sides of the Yangtze River, including Longhu Lake, Daguan Lake, Wuchang Lake, Bohu Lake, Huang Hu Lake, Caoqing Lake, Caizi Lake, Jinsheng Lake, Yaochen Lake, Chaohu Lake, Danyang Lake, Shijiu Lake and Nanyi Lake. Xin 'anjiang River is the upper reaches of Qiantang River, and the source water flows out from the east slope of Liugujian in Xiuning County. After the confluence of Tunxi and Hengjiang, it is called Xin 'anjiang, which flows through Shen Du to the provincial boundary and enters the Zhejiang boundary. The province is 87 kilometers long from Tunxi to Jiekou. Xin 'anjiang has sixty-four tributaries, including Lvshui River, Huangjiang River, Lianjiang River, Shendu River, Fengle River, Bushe River and Fuzi River. Generally, the velocity is faster, the riverbed is narrower and there are many bends.

Anhui province belongs to the transition zone between warm temperate zone and subtropical zone in climate, with warm temperate semi-humid monsoon climate to the north of Huaihe River and subtropical humid monsoon climate to the south of Huaihe River. The annual average temperature is below 150℃ in Huaibei and Dabie Mountains, above 16℃ along the Yangtze River and southern Anhui, between 15℃ and 16℃ in other areas, and the temperature difference between the north and the south is above 2℃. 1 Monthly average temperature-1℃-4℃, the temperature difference between north and south is about 5℃, and the average temperature in July is 27℃-29℃, with little difference between north and south. In the spring, the difference between north and south can reach half a month. 1000 mm isorainfall line runs through Chaohu Lake and across the central part of Jianghuai. The average annual precipitation in the north of this line is below 1000 mm, which is a semi-humid area, and the south is above 1000 mm, which is a humid area. Because Anhui is located in the mid-latitude zone, the weather situation is changeable, the terrain is diverse, the cold and warm air mass activities are frequent, the precipitation changes greatly during the year, and natural disasters such as drought, waterlogging, wind hail and freezing are frequent.