Glaciers

According to the location of the ice fall on the mountain and covering. The shape of mountain glaciers depends on the surrounding terrain and the slope of the surface. Glaciers slide down the slope under the force of gravity. Ice sheets can be placed on a flat, level terrain. In form they resemble a round loaf. Formation of glaciers in areas where accumulated over a long winter snow does not have time during the summer melt. Level below which melted all the snow accumulated in winter, called the snow line. This line can be seen in the mountains at the end of the summer: it separates the upper part of the dazzling white snow-free slopes from the dark bottom. Most of the glaciers is above the snow line, but "language" of some of them down and below. Sometimes they end among the hills, covered with green forests, as can be seen in New Zealand. The snow line in different places of the globe lie at different heights, depending on the climate. Above all it is in the tropics - very hot and dry on Earth. To the equator line number is omitted, because there are a lot of rain falls. As we approach the poles of the snow line is getting lower. And in Antarctica descends to sea level. But not only the climate controls the glaciers. Large and the impact of ice on the climate itself. Especially great influence Antarctica, where winter temperatures drop to minus some 80 °, and huge masses of ice have a constant temperature of minus 30 to minus 50 degrees. This is a giant refrigerator on our planet. His influence extends to the entire globe. In the Arctic, the main source of cold - floating sea ice, and glaciers, which cover many islands, including the largest island on Earth - Greenland. And in the Arctic and Antarctic ice reflects up to 80 percent of solar energy. And, despite the fact that the sun here does not go beyond the horizon throughout the year, they still remain cold and melt a little. Vast tracts of ice at the poles - one of the main causes of contemporary geographic zoning on the Earth. Were it not for these ice in the polar regions would be much warmer. And then the Earth's climate would have been softer and smoother at all latitudes. Geologists study suggests that it is so, and was the Earth's climate millions of years ago when the glaciers on Earth has ever had. All glaciers, irrespective of their size and shape, moving. The reason is the property of ice. Though he seems solid, but at the same time, he is fragile. At a large thickness by gravity ice becomes plastic and acquires the ability to flow. The thickness of most of the glacier is big enough to cause them to flow, although it may be very different: from 100 meters on most mountain glaciers up to 3-4 miles in Antarctica and Greenland. Ice can move a continuous stream. But the glacier is, broken cracks in separate blocks. Cracks show uneven movement of the glacier. The velocity of the glaciers is not the same. The most moving glaciers are in Antarctica and Greenland. They are for the year distance in kilometers and more. Many glaciers in the Alps, the Caucasus and crawl around a hundred meters per year, and larger - in the Tien Shan and Pamir - usually moved in a year to 150-300 meters. It is known that in the life of the glaciers has never been a period when they would have remained unchanged. Due to variations in climatic conditions or the glaciers grow or recede. Hundreds of thousands of years ago glaciers on Earth has reached nearly three times more space than they do now. The existing glaciers - the remnants of an extensive Quaternary glaciation. This glaciation occurred more than a million years ago, and since then the glaciers have become an integral part of the nature of the Earth. Glaciers - it is also the greatest repositories of fresh water. Snowflake that hit the surface of the glacier, rests here for many years before it melts. A melt waters of glaciers give rise to rivers. Many of them emerging from the mountains flow through the fertile but arid piedmont plains. Annually melted only a very small fraction of the mass of the glacier. These glacial melt water are, for example, 'Central Asia, about one third of the rivers flow. In some particularly dry years, this amount of water is not enough. Increase the stock can be achieved by artificially enhancing the melting glacier. To this end, the surface is sprinkled with a thin layer of dark powder, such as coal dust. Because of the white surface reflects sunlight, and dark matter on the contrary, it is absorbed. Ice heats up more, the melting increases and runoff into the river rises.