Introduction to the geographical location of the United States

American geography: topography and rivers

The topographical features of the United States are that the east and west sides are high and the middle is low, and the mountains all run north and south. The Appalachian Mountains in the east extend from northeast to southwest, parallel to the Atlantic coast. There are abundant coal resources on both sides of the mountain, accounting for 1/5 of the national reserves and 3/4 of the output. It is an important coal base in the United States. The Rocky Mountains in the west are called the backbone of North America. The mountain is 500 kilometers wide, and the peaks in the western part of the United States soar into the sky, erecting a natural barrier for the central part on the plain. The central part is the great plain, accounting for 1/2 of the national territory. The swift Mississippi River flows through the central plain, making it an important agricultural area in the United States.

There are many rivers in the United States, which are divided into two major water systems by the Rocky Mountains: the western part is the Pacific water system, and the main rivers are the Colorado River, the Columbia River and the yukon river. To the east is the Atlantic water system, which is divided into rivers flowing into the Atlantic Ocean and rivers flowing into the Gulf of Mexico. The former includes Hudson River, Delaware River and Potomac River; The latter mainly includes the Mississippi River. Climate and time zone

The United States is located in the north temperate zone, and most areas have a continental climate. Due to the vast territory, complex terrain and different airflow, the climate in different parts of the country is very different, which is mainly divided into five climatic zones.

1. Climate of continental temperate broad-leaved forest

Leng Xia has a cool continental temperate broad-leaved forest climate in the northeast coast and the Great Lakes region in winter. Winter in this area is very cold, and there are often snowstorms. In June+10/October, 5438, the average temperature was about -6℃, and the Great Lakes Ice Age lasted for five months. Summer is mild and rainy, and the average temperature in July is 10℃. The average annual rainfall is 1000 mm.

2. Subtropical forest climate

The southeast coast and the Gulf Coast belong to subtropical forest climate, with warm winters and cool summers. The winter in this area is warm and rainy, and the average temperature in 65438+ 10 is about 9℃. Summer is cool and humid. The average temperature in July is 23℃~27℃, and the average annual rainfall is more than 2000 mm ... But it is often hit by hurricanes in late summer and early autumn every year.

3. Continental climate

The central plain has a continental climate, with cold and snowy winters and hot and rainy summers. The annual rainfall along the Mississippi River reaches 65,438+500mm. The annual precipitation in the northern part of the Central Plains is only about 500 mm, and the annual temperature difference varies greatly.

4. Inland climate

The inland plateau and mountainous areas in the west belong to the inland climate, which is dry, cold and snowy in winter and hot and rainy in summer. Rocky Mountain, Cascade Mountain and Sierra Nevada in this area have alpine climate, and the temperature decreases with the increase of mountainous terrain.

5. Maritime climate

The coastal areas of the Pacific Ocean have a maritime climate. The northern region is warm in winter and cool in summer, with abundant rainfall. The average temperature in 65438+ 10 is above 4℃, the average temperature in August is below 14℃, and the annual rainfall is above 1 500 mm. It is the region with the best climatic conditions along the Pacific coast. The south has a Mediterranean climate, with warm and rainy winters, and the average temperature in June is 12℃. Summer is dry and sultry. The average temperature in August is about 35℃, and the annual rainfall is between 300-500mm.

The United States, from the Atlantic coast to the Pacific coast, is nearly 4,500 kilometers, spanning 60 longitudes, and Alaska exceeds 1 10 longitudes. The whole country is divided into eight standard time zones, starting from the Atlantic coast, which are Atlantic time zone, eastern time zone, central time zone, mountain time zone, Pacific time zone, Yukon time zone, Alaska Hawaii time zone and Bering time zone in turn.

There are four main time zones on the mainland: East, Central, Mountain and Pacific Ocean. Among them, it is famous for the eastern time zone where the capital Washington is located. All major historical moments in the United States are based on Eastern Time, which is 5 hours later than Greenwich Mean Time and 13 hours later than Beijing Time.

In the United States, except Michigan and Arizona, all other states implement daylight saving time. That is to say, every year from 2 am local time on the last 1 Sunday in April to 2 am local time on the last 1 Sunday in October, the clock is set forward 1 hour. Population and nationality

Since the founding of People's Republic of China (PRC), the United States has conducted a census every 10 years. According to the census statistics of 1990, the national population is 249 million, including 5 1. 1% for women and 48.9% for men. The agricultural population accounts for 1.2% of the total population. The national population is increasing by about 2.3 million people every year.

America is a multi-ethnic country. According to a Chinese newspaper in the United States, the United States has gathered descendants of 155 nationalities in the world, the most important of which are whites, Indians, blacks and Asians.

At present, there are more than 65438+600 million Chinese in the United States. In the late 1940s, the United States recruited a large number of Chinese workers from China, Fujian and Guangdong to develop the western region. These Chinese laborers have gone through hardships across the ocean and engaged in heavy manual labor such as mining, reclamation, river digging and road building in the western United States. Since the end of 19 th century, the United States has passed various anti-China legislation, and Chinese in China have been persecuted, resulting in a sharp drop in the number of Chinese immigrants. In this harsh environment, China people finally survived tenaciously, took root in the United States and started a career. For more than a century, the political status, economic status and social status of Chinese have been continuously improved. At present, the family income and education level of China people are higher than the national average. College graduates account for 36% of China's population, which is 20 percentage points higher than the national average. At present, among the first-class scientists and engineers in the United States (about1.2000), China people account for as much as 30000. In American universities, more than 10000 people from China hold positions of assistant professors or above. They have made great contributions in science, technology and education, among which six China people have made outstanding contributions. Won the Nobel Prize in Physics and Chemistry. They are Professor Yang Zhenning of new york State University; Li Zhengdao, a professor at Columbia University; Professor Ding Zhaozhong of Massachusetts Institute of Technology; Li Yuanzhe, a professor at the University of California at Berkeley; Steven Chu, a professor at Stanford University; Cui Qi, a professor at Princeton University.