First, the basic concept?
Xi 'an, formerly known as Chang 'an and Haojing, is now the capital of Shaanxi Province, a sub-provincial city and a national regional central city (northwest). It is an important central city in western China approved by the State Council and an important scientific research, education and industrial base of the country. Xi is one of the four ancient capitals in China, a "world historical city" determined by UNESCO 198 1, and one of the top ten ancient capitals in the world selected by American media.
Chang 'an has been the imperial capital since ancient times. Xi 'an has a history of more than 5,000 years of civilization, a history of building a city of 3 100 years and a history of building a capital of 165438 years. It is one of the four ancient capitals in China, one of the important birthplaces of Chinese civilization and the Chinese nation, and the starting point of the Silk Road. Fenghao Capital, Qin Xianyang Palace, Terracotta Warriors, Han Weiyang Palace, Changle Palace, Sui Daxing City, Tang Daming Palace, Xingqing Palace, etc. Outline the "Chang' an Complex". ?
Xi is the best tourist destination in China, one of the civilized cities in China and an important science and education center in China. There are 7 985 or 2 1 1 engineering universities, including Xi Jiaotong University, Northwestern Polytechnical University and xidian university.
At present, six heritages in Xi 'an are listed in the World Heritage List, namely, the Mausoleum of Qin Shihuang and Terracotta Warriors, the Wild Goose Pagoda, the Little Wild Goose Pagoda, the Daming Palace Site in Chang 'an in Tang Dynasty, the Weiyang Palace Site in Chang 'an in Han Dynasty and the Xingjiao Temple Tower.
Two. Location and background
Xi City is located in Guanzhong Basin in the middle of Weihe River Basin, with east longitude 107.40 ~ 109.49 degrees and north latitude of 33.42 ~ 34.45 degrees, bordering Weihe River and Loess Plateau in the north and Qinling Mountains in the south. The eastern part is bounded by Zero River and Yuanqiu Mountain, and is connected with hua county, Weinan, Shangzhou and Luonan counties. The western part is bounded by Taibai Mountain and Qinghai Loess Plateau, bordering Meixian County and Taibai County. South to the main ridge of the North Qinling Mountains, bordering Foping County, ningshan county County and Zhashui County; It reaches Weihe River in the north and crosses Weihe River in the northeast, and is adjacent to Xianyang City, Yangling District and Sanyuan, Jingyang, Xingping, Wugong, Fufeng and Fuping counties (cities). It is about 204 kilometers long from east to west and about 1 16 kilometers wide from north to south. It covers an area of 9983 square kilometers, including urban area 1066 square kilometers.
Three. geology
The geological structure of Xi 'an is divided into two units: Qinling geosyncline fold belt and North China platform. 65.438+0.3 billion years ago, during the Yanshan Movement, a big fault occurred at the northern foot of Qinling Mountains. Since the Neogene about 3 million years ago, the neotectonic movement in the Qinling geosyncline fold belt south of the great fault has been extremely active, and the mountains have fallen sharply from north to south, creating the Qinling Mountains. At the same time, the Weihe fault depression, which belongs to the North China platform to the north of the great fault, continued to subside, and the Weihe plain was formed under the joint action of aeolian loess cover and Weihe alluvial. [3]
Four. topography
Xi 'an ranks first in China in terms of altitude difference. The Qinling Mountains, with its steep and beautiful peaks, and the wide and flat Weihe Plain have clear boundaries, which constitute the main landforms of Xi 'an. The main peak of Qinling Mountain is 2000-2800 meters above sea level, among which the main peak of Taibai Mountain in the southwest is 3867 meters above sea level, which is the highest peak in the central part of the mainland. Weihe plain is 400-700 meters above sea level, of which the lowest point of Weihe river bed in the northeast is 345 meters above sea level. The urban area of Xi is built on the second terrace of Weihe Plain.
Verb (abbreviation for verb) climate
Xi is a warm temperate semi-humid continental monsoon climate with four distinct seasons. But the climate is changeable in spring, hot and rainy in summer, cool and rainy in autumn and dry and cold in winter. Annual average temperature 13 degrees Celsius.