Jiangnan geographical environment

Literally means Jiangnan, Jiangnan is endless. In a narrow sense, it refers to the south bank of the middle and lower reaches of the Yangtze River. These areas include areas south of the Yangtze River in Jiangsu, areas south of the Yangtze River in Anhui, and areas north of Qiantang River in Shanghai and Zhejiang.

Jiangnan in a broad sense includes the whole territory of Shanghai, Jiangxi, Hunan and Zhejiang, as well as the areas south of the Yangtze River in Jiangsu, Anhui, Hubei and Shanghai. Compared with Jiangnan Road in Tang Dynasty, there are fewer parts involving Guizhou Province. Northern Fujian is sometimes called Jiangnan. In a broad sense, Jiangnan has a vast territory and diverse landforms, so it is often regarded as "Great Jiangnan", which is roughly consistent with the meteorological scope of Jiangnan. Four rice markets and four famous buildings in Jiangnan are all within the scope of Jiangnan. This area includes three famous mountains, three rivers and three lakes-Qiantang River and Taihu Lake in Huangshan, Ganjiang River and Poyang Lake in Lushan, Xiangjiang River and Dongting Lake in Hengshan. These three rivers and lakes are the cradles of Wu culture, Jiangxi culture and Huxiang culture respectively. The definition of "Great Jiangnan" begins with the ancient division (Jiangnan Road) and is often described in literary works. For example, Du Fu's Random Encounter Li Guinian was written in Changsha. The Jiangnan referred to in the weather forecast is roughly the Jiangnan zone in a broad sense.

The word "Jiangnan" has also been used for administrative divisions in official geographical records since the Yuan Dynasty. Jiangnan provinces in the early Qing Dynasty, that is, Jiangsu, Anhui and Shanghai are now collectively called Jiangnan. Suzhou, Songjiang, Changzhou, Zhenjiang, Jiangning, Hangzhou, Jiaxing and Huzhou are also the most representative administrative places in the Qing Dynasty. During the Ming and Qing Dynasties, Raozhou Prefecture, Jiujiang Prefecture and Nanchang Prefecture in Jiangxi Province and Chizhou Prefecture, Taiping Prefecture, Ningguo Prefecture and Huizhou Prefecture in Anhui Province were also very representative Jiangnan areas. Compared with the north, the most obvious feature of the terrain in the south of the Yangtze River is that it is plain and watery. Jiangnan is located in the plain of the middle and lower reaches of the Yangtze River, with high terrain in the south and low terrain in the north. Its northern part is flat, mainly plain, and there are some mountains and hills in the south. In addition to abundant precipitation, there are two major water systems in the south of the Yangtze River and Qiantang River, which are connected by canals. There are many rivers and lakes in the south of the Yangtze River. There are three famous freshwater lakes in China, namely Dongting Lake in Hunan, Poyang Lake in Jiangxi and Taihu Lake in Jiangsu and Zhejiang. In the long-term development process, a large number of water conservancy projects have been built to make them interrelated, such as Taibo Kaibodu, Wu Zixu Kaixuxi, Fu Cha digging the Han River and Jiangnan Canal. Therefore, it has always enjoyed the reputation of "water village".

The physical geography of the south of the Yangtze River formed under such climate and topography is significantly different from that of the north. The ancients described it like this:

Wu Jun and Zhu Shu is one of the most outstanding landscape sketches in the Southern Dynasties. His description of the natural scenery from Fuyang to Tonglu can quite reflect the beauty of the natural scenery in the south of the Yangtze River:

The wind and smoke are clean, the Tianshan Mountains are colorful, and everything comes from the stream. From Fuyang to Tonglu, Baili, Strange Mountains and Different Waters, chinese odyssey. The water is blue, with thousands of feet at the bottom; You can swim with the fine stones and look directly at them. If fierce wave rushes, how fast the arrow will go. The mountains near the shore are all cold trees, competing for novelty and beauty, competing for the high finger peak. The spring stirs the stone and keeps ringing; Good birds sing, they rhyme. Cicadas are endless, and apes are endless. Those who fly kites against the sky look at the peak and rest their hearts, while those who govern the world look at the valley and forget to betray. The horizontal branches are covered, and the day is still faint; The thin strips set each other off, and sometimes the sun shines.

Tao Hongjing's "Chinese Thank You Book" even praised Jiangnan as "the fairy capital of desire", and its words are also very attractive:

The beauty of mountains and rivers has existed since ancient times. The mountain peaks soar into the sky and the streams are crystal clear. The stone walls on both sides are colorful and set each other off. Green Woods, green bamboo clusters, four. The morning mist will rest, and apes and birds will sing; As night fell, the scales began to beat. This is really a fairyland on earth. Lingyun in Kasper? in the Southern Dynasties, so far no one can appreciate its wonders.

There is also a saying in Shi Shuo Xin Yu Ci: "Prince Jing Yun:' Walking on the mountain road, mountains and rivers set each other off, which is overwhelming, especially in autumn and winter'," Gu Changkang returned home from the benefits, and people asked about the beauty of mountains and rivers, and Gu Yun:' Thousands of rocks compete, and thousands of valleys compete' ",but in the Tang Dynasty, with the economic and cultural development of Jiangnan,

Outside the willow gate, there is a long waterfront. Go to the temple by boat and drive to other people's homes. Citrus reticulata, jathyapple, Bai Lianhua in the autumn wind. Jiang Tian's poems are in good condition, so don't take credit for going back to Japan. (Zhang Ji's "Send Brother Dai Xuan to Suzhou")

Guzhushan county, Liu will draw. Looking at the battlements from a distance, there are all Shui Yunjian. (Zheng Gu's "Uncle gives a gift to Huzhou")

In the past few years, I have traveled all the way to the east of Wu Ting, singing and traveling. There is no clue to Qingtai Temple, and there are many restaurants by the Green Water Bridge. (One of Du Mu's Two Poems of Runzhou)

In modern times, Mr. Wang Bijiang thought: "Jiangsu and Zhejiang are both the territory of Yangzhou, Gong Yu, and the so-called wealth in the world is also Austria." Its terrain, the Soviet Union has the difference between the north and the south, but they all cross the river near the sea, with mountains and rivers far away and lakes lingering; Zhejiang has a quiet landscape, which is also beautiful with its neighbors in Fujian. "The words quoted above fully show the unique beauty of the landscape in the south of the Yangtze River.

Hilly areas in the south of the Yangtze River

South of the Yangtze River, north of Nanling Mountain, west of Wuyi Mountain and Tianmu Mountain, east of Xuefeng Mountain, including southern Hunan and Jiangxi provinces in China, as well as large areas of low mountains and hills in western Zhejiang and southern Anhui, are collectively called Jiangnan Hills. It is located between latitude 25 ~ 3 1 n and longitude10 ~120, covering an area of about 370,000 square kilometers.

Since Mesozoic, the southern uplift and the northern fault subsidence have formed a terrain inclined to the north. The main part can be regarded as a large depression adjacent to Hunan and Jiangxi provinces, with mountains in the southeast and west. Surface runoff flows into Dongting Lake and Poyang Lake through Xiangjiang River, Zishui River, Yuanjiang River, Lishui River, Poyang Lake, Xinjiang River, Fuhe River, Ganjiang River and Xiushui respectively, and then flows northward into the Yangtze River. The mountainous hills in the northeastern border area of Zhejiang and Anhui are connected with those in the border area of Zhejiang and Jiangxi, which has become a watershed for the Yangtze River and Zhejiang and Fujian to flow into the seawater system independently. There are many middle mountains and low mountains in the area, which are arranged in northeast-southwest direction, and the Neocathaysian structural system is clear. The altitude of the mountain is about 1000m, and it can reach 1500 ~ 2000m locally. The main mountain ranges are Mufu Mountain, Jiuling Mountain, Wugong Mountain, Wanyang Mountain and Zhuguang Mountain, Tianmu Mountain and Xianxialing Mountain in western Zhejiang, Wuyishan Mountain in Fujian and Jiangxi, and Huangshan Mountain in southern Anhui. Lushan, Hengshan, Huangshan, Jiuhua, Tianmu Mountain and Jinggangshan are all famous tourist attractions.

Jinqu basin

Jinqu Basin is one of the few basins and plains in Zhejiang Province, including Jinhua and Quzhou. It has been rich since ancient times and has the reputation of "the cornucopia of Zhejiang". As the birthplace of Qiantang River, the river is clear and is the mother river of Zhejiang people. Description of the division of meteorological geographical areas at the national level:

Jiangnan region: Hubei, Hunan, Jiangxi, Zhejiang, Anhui (south), Jiangsu, Shanghai and northern Fujian (extending eastward from Nanling).

Description of the division of national secondary meteorological geographical areas:

Jiangnan area: The north-south basic Zhejiang-Jiangxi and Hunan-Guizhou railway lines are divided into south and north, and the east and west are basically divided into east, middle and west by the north-south extension line between northeast Jiangxi Province and Zhejiang and the boundary line between Jiangxi and Hunan.

As we all know, Jiangnan is located in the transition zone from subtropical zone to warm temperate zone, with warm and humid climate and distinct seasons, which is very suitable for the growth of various crops and the survival of human beings. Although the climate in the south of the Yangtze River is not invariable in history, according to some data, the sudden interruption of Liangzhu culture in Taihu Lake Basin is actually directly related to the catastrophic natural floods caused by land subsidence, rainfall increase and sea level rise in Taihu Lake Basin. Many Liangzhu cultural sites, such as Wujiang Meinian, Yuanjiadai and Dasanjin, are generally covered with a layer of peat, indicating that this place has been flooded. In addition, according to Zhu Kezhen's book "Preliminary Study on Climate Change in China in the Last Five Thousand Years", the climate in China has a general trend of gradually changing from warm and humid to cold and dry. But overall, the climate change in Jiangnan area is smaller than that in other areas. Huang's book A Brief Introduction to the Economy of the South of the Yangtze River in Qin and Han Dynasties holds that the climatic conditions in the south of the Yangtze River in Qin and Han Dynasties have the following characteristics: first, the farming period with high temperature, the growing period with daily average temperature greater than 0℃, the active growing period with plants greater than 10℃, and the suitable growing period with warm crops greater than15℃; Second, there is abundant precipitation. The annual precipitation in the areas north of the Yangtze River and Qiantang River is more than 800 mm-1600 mm, and in the hilly areas of the Yangtze River, it is more than 1600 mm, which provides abundant water sources for various crops. After Qin and Han dynasties, although the specific climate index will change, the overall characteristics of mild climate and sufficient rainfall have not changed much. Compared with the dry and cold in the north and the humid and hot in Lingnan, the human body is very comfortable in the climate of Jiangnan.