The geological structure of Tianjin is complex, and most of it is covered by Cenozoic sediments. The terrain is dominated by plains and depressions, with low mountains and hills in the north, and the altitude gradually decreases from north to south.
The highest in the north, with an altitude of1052m; The lowest in the southeast, 3.5 meters above sea level. The highest peak in the city: Jiushan Peak (elevation1078.5m). The general outline of the landform is high in the northwest and low in the southeast.
The terrain is divided into three types: mountains, hills and plains, and the plains account for about 93%. Except the mountainous area bordering the southern foot of Yanshan Mountain in the north, the rest are alluvial plains, and the mountainous area in the north of Jixian County is a low mountain and hill below 1000 meters above sea level.
Extended data:
I. Location and background
Tianjin is located in the north of North China Plain, bordering Bohai Sea in the east and Yanshan Mountains in the north, between east longitude116 43' and north latitude1/8 04' and 38 34' and 4015'. The city center is located at east longitude 1 17 10' and north latitude 39 10'.
Located in the lower reaches of the Haihe River, it spans both banks of the Haihe River, with a length of 189 km from north to south and a width of 1 17 km from east to west. The land boundary is 1 137 km long and the coastline is 153 km long. It is the traffic throat of Beijing's railway to Northeast China and East China and the port of ocean transportation. It is known as the "river-sea hub" and the "gateway to Kyrgyzstan".
Second, climate.
Tianjin is located in the north temperate zone, on the east coast of Eurasia in mid-latitude, and is dominated by monsoon circulation. It is an area where East Asian monsoon prevails, and belongs to warm temperate semi-humid monsoon climate. Near Bohai Bay, the influence of marine climate on Tianjin is obvious.
The main climatic characteristics are: four distinct seasons, windy spring, drought and little rain; Summer is hot and the rain is concentrated; Autumn is cool and the temperature is moderate; Winter is cold, dry and snowy, so late spring, early summer and autumn are the best seasons to travel to Tianjin.
There is northerly wind in Dorsey in winter, with low temperature and little precipitation. In the summer half year, the subtropical warm high pressure in the Pacific Ocean is strengthened, with southerly winds as the main factor, high temperature and heavy precipitation. Sometimes there is a spring drought. The average annual temperature in Tianjin is about 14℃, and it is the hottest in July, with an average monthly temperature of 28℃. The highest temperature in history is 4 1.6℃.
Three. water resource
Tianjin straddles the banks of the Haihe River, which is the largest river in northern China. There are more than 300 tributaries, the upstream length of which exceeds 10 km, and it flows into the North Canal, Yongding River, Daqing River, Ziya River and South Canal near the middle reaches.
Five rivers merge into the Haihe River at the Sanchakou near Tianjin Jingang Bridge and enter the sea from Dagukou. The main stream is 72 kilometers long, with an average river width of 100 meter and a water depth of 3-5 meters. Historically, this river was navigable for 3000 tons of seagoing ships.
There are 19 first-class rivers flowing through Tianjin, with a total length of 1095.438+0 km. There are also six artificial rivers, including Ziya New River, Liu Du Reduction River, Machang Reduction River, Yongding New River, Chaobai New River and Returning Home New River, with a total length of 284.5438+0 km.
There are 79 secondary rivers, with a total length of 1363.4km and deep canals 106 1, with a total length of 4578km. Tianjin has also transferred water from the Yellow River to Tianjin many times, and there is a certain amount of groundwater.
References:
Baidu Encyclopedia-Tianjin