What is an Ice Sheet?

Ice caps, also called continental glaciers, are land areas (usually common in plateau areas) that cover a large area of ice, covering an area of less than 50,000 square kilometers. Generally refers to continental glaciers. Antarctica and Greenland are two large ice caps. The ice sheet is not tied to geographical features.

An ice sheet refers to the land area of a very thick layer of ice covering a large area, referred to as an ice sheet. Antarctic and

The Antarctic ice sheet began at the end of the Oligocene. Reached its current size at least 5 million years ago. The ice sheet is mostly distributed in the Antarctic Circle, with a diameter of about 4,500 kilometers and an area of about 13.98 million square kilometers.

The Antarctic ice sheet is composed of two parts, east and west, bounded by the transversal Antarctic Mountains.

The Antarctic ice sheet is a cold glacier. It is characterized by low temperature, small accumulation and ablation, and slow ice formation. For example, the plateau process (79 ° 15 south latitude, 40 ° 30 east longitude) requires 3500 years to form ice, so it is relatively stable. The Antarctic ice sheet is the driest and coldest region on earth. The annual average temperature inside the plateau is as low as -55 ° C, and the annual precipitation is less than 50 mm. The ice surface does not melt all year round, and the ice formation process is extremely slow. The average annual temperature at the edge of the ice sheet is -10 to -15 ° C, the highest and lowest temperatures are 10 ° C and -40 ° C, respectively, and the annual precipitation is 200 to 500 mm. In summer (November to February of the following year), snow and ice melt strongly. The altitude of the ablation zone is below 1000 to 1400 meters, and the height of the snow line is between 0 to 100 meters. Therefore, the inland Antarctic ice sheet is a typical polar continental glacier, and the coastal zone and the Antarctic Peninsula have the characteristics of polar marine glaciers. The Antarctic ice sheet is the largest ice storage and cold source on the planet.

The driving force behind the global atmospheric circulation is solar thermal energy. The sun sends thermal energy to the earth, but the solar thermal energy received by the earth is uneven. The area near the equator receives more heat and high temperature, and the poles receive less heat and low temperature. The temperature difference between the equator and the poles can reach 100 ° C. This is due to the difference in the length of time and the angle of the light. The atmosphere over the equator rises due to thermal expansion, flows to the poles, cools down at the poles, and returns to the equator, forming a global atmospheric circulation. However, if there is no temperature difference between the two poles, there will be no atmospheric circulation. ^[2]