美国自然地理.pptVIP

Brief Introduction of the United States National Flag: The Stars and Stripes (2) National emblem: Eagle The Star Spangled Banner the Lyrics come from “Defense of Fort McHenry” written by Francis Scott Key （3）National Anthem The Star-Spangled Banner 《星条旗永不落》 Geographical Features The United States is located in the central part of North America, except Alaska and Hawaii. The country is bordered by Canada on the north, Mexico and Gulf Mexico on the south, the Atlantic Ocean on the east and the Pacific Ocean on the west. The total area of the USA is 9,629,091square kilo- meters (the area of land is 9,158,960 square km). It is the fourth largest country in the world which exceeded in size only by Russia, Canada and China. The length of land is 4,500km, the width is 2,700km and the coastline is 22,680km. The Great Lakes Weather and Climate in USA The humid east The arid west The humid-arid transition The humid pacific coast Due to the immense size and spread of topology in the US the climate is incredibly varied. If there is a general climate then it is temperate, but it is also tropical in Florida and Hawaii, arctic in Alaska, arid in the Great Basin of the southwest and semi-arid in the Great Plains to the west of the Mississippi River. The temperature range runs between the extremes of 57 degrees C during the summer months in Californias Death Valley to -62 degrees C in Alaska, with every other shade in between. The northern states are the coldest, with bitter, freezing winters - especially in the plains, Midwest and Northeast. Low temperatures in January and February in the Northwest are occasionally tempered by warm chinook winds from the eastern slopes of the Rocky Mountains. In contrast, the southern states are known as the Sunbelt, where it rarely drops below freezing. Hot summers are the norm throughout the US, except in New England, Oregon and Washington state, all of which are rainier and less predictable than the rest of th