文档介绍：4. Exploring the :Antaretica
Antarctica1 is the highest, driest and coldest continent.
Its million square miles make it larger than Europe. At its widest point, Antarctica is about 4,000 miles across. There are about 98% thick continental ice sheet and 2% barren2 rock. The average thickness of the ice sheet is 7,200 feet; this amounts to 90% of all the ice and 70% of all the fresh water in the world. If the ice cap were to melt, the sea level would rise by an average of 230 feet. Mountain ranges up to 4897 meters high. Glaciers3 form ice shelves4 along about half of the coastline, and floating ice shelves constitute 11% of the area of the continent.
Severe low temperatures vary with latitude5, elevation6, and distance from the ocean; East Antarctica is colder than West Antarctica because of its higher elevation. Antarctic Peninsula7 has the most moderate climate. Higher temperatures occur in January along the coast and average slightly below freezing. Average temperatures are never above 32 degrees Fahrenheit8, even in summer. In winter, the temperature averages minus 76 degrees.
The Pole is actually a desert environment, averaging about the same amount of monthly rainfall as the Sahara Desert9.
In October 1991 it was reported that the ozone shield, which protects the Earth's surface from harmful ultraviolet10 radiation, had dwindled11 to the lowest level recor