Global Warmig
Páginas: 6 (1410 palabras)
Publicado: 23 de julio de 2012
Glaciers…
I hope you are having a good day, because today my team and I will talk about the Glaciers. A glacier is a large persistent body of ice. Originating on land, a glacier flows slowly due to stresses induced by its weight. The crevasses and other distinguishing features of a glacier are due to its flow. Another consequence of glacier flow is the transport of rock and debris abraded fromits substrate and resulting landforms like cirques and moraines. A glacier forms in a location where the accumulation of snow and sleet exceeds the amount of snow that melts. Over many years, often decades or centuries, a glacier will eventually form as the snow compacts and turns to ice. A glacier is distinct from sea ice and lake ice that form on the surface of bodies of water.
FormationGlaciers form where the accumulation of snow and ice exceeds ablation. As the snow and ice thicken, they reach a point where they begin to move, due to a combination of the surface slope and the pressure of the overlying snow and ice. On steeper slopes this can occur with as little as 15 m (50 ft) of snow-ice. The snow which forms temperate glaciers is subject to repeated freezing and thawing, whichchanges it into a form of granular ice called firn. Under the pressure of the layers of ice and snow above it, this granular ice fuses into denser and denser firn. Over a period of years, layers of firn undergo further compaction and become glacial ice. Glacier ice has a slightly reduced density from ice formed from the direct freezing of water. The air between snowflakes becomes trapp ed andcreates air bubbles between the ice crystals.
The distinctive blue tint of glacial ice is often wrongly attributed to Rayleigh scattering due to bubbles in the ice. The blue color is actually created for the same reason that water is blue, that is, its slight absorption of red light due to an overtone of the infrared OH stretching mode of the water molecule.
Types of glaciers
Glaciers arecategorized in many ways including by their morphology, thermal characteristics or their behavior.
Alpine glacier
Alpine glaciers form on the crests and slopes of mountains and are also known as "mountain glaciers", "niche glaciers", or "cirque glaciers".
An alpine glacier that fills a valley is sometimes called a valley glacier.
Continental Glaciers
The largest glacial bodies, ice sheetsor continental glaciers, cover more than 50,000 km².
Tidewater glaciers
Tidewater glaciers are glaciers that terminate in the sea. As the ice reaches the sea pieces break off, or calve, forming icebergs. Most tidewater glaciers calve above sea level, which often results in a tremendous splash as the iceberg strikes the water. If the water is deep, glaciers can calve underwater, causingthe iceberg to suddenly leap up out of the water.
Temperate glacier
A temperate glacier is at melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below freezing point from the surface to its base, although the surface snowpack may experience seasonal melting. A sub-polar glacier has both temperate and polar ice, depending on the depth beneaththe surface and position along the length of the glacier.
What happens with glaciers in global warming?
Hundred of glaciers an ice caps on every continent that global warming is severely affecting the water and glacial cycles of the planet. This is a profound change that unlike natural cycles like the Little Ice Age of the 16th and 17th centuries is proceeding very rapidly and appears tied to nonatural cycles. The best correlation for this change to all but a handful of the 160,000 land glaciers and parts of the great ice caps is to rising atmospheric temperatures tied to increasing amounts of greenhouse gases.
As more and more water reaches the ocean, it is increasing sea level at a faster rate --- which threatens every coastal city and shoreline. New scientific projections show at...
I hope you are having a good day, because today my team and I will talk about the Glaciers. A glacier is a large persistent body of ice. Originating on land, a glacier flows slowly due to stresses induced by its weight. The crevasses and other distinguishing features of a glacier are due to its flow. Another consequence of glacier flow is the transport of rock and debris abraded fromits substrate and resulting landforms like cirques and moraines. A glacier forms in a location where the accumulation of snow and sleet exceeds the amount of snow that melts. Over many years, often decades or centuries, a glacier will eventually form as the snow compacts and turns to ice. A glacier is distinct from sea ice and lake ice that form on the surface of bodies of water.
FormationGlaciers form where the accumulation of snow and ice exceeds ablation. As the snow and ice thicken, they reach a point where they begin to move, due to a combination of the surface slope and the pressure of the overlying snow and ice. On steeper slopes this can occur with as little as 15 m (50 ft) of snow-ice. The snow which forms temperate glaciers is subject to repeated freezing and thawing, whichchanges it into a form of granular ice called firn. Under the pressure of the layers of ice and snow above it, this granular ice fuses into denser and denser firn. Over a period of years, layers of firn undergo further compaction and become glacial ice. Glacier ice has a slightly reduced density from ice formed from the direct freezing of water. The air between snowflakes becomes trapp ed andcreates air bubbles between the ice crystals.
The distinctive blue tint of glacial ice is often wrongly attributed to Rayleigh scattering due to bubbles in the ice. The blue color is actually created for the same reason that water is blue, that is, its slight absorption of red light due to an overtone of the infrared OH stretching mode of the water molecule.
Types of glaciers
Glaciers arecategorized in many ways including by their morphology, thermal characteristics or their behavior.
Alpine glacier
Alpine glaciers form on the crests and slopes of mountains and are also known as "mountain glaciers", "niche glaciers", or "cirque glaciers".
An alpine glacier that fills a valley is sometimes called a valley glacier.
Continental Glaciers
The largest glacial bodies, ice sheetsor continental glaciers, cover more than 50,000 km².
Tidewater glaciers
Tidewater glaciers are glaciers that terminate in the sea. As the ice reaches the sea pieces break off, or calve, forming icebergs. Most tidewater glaciers calve above sea level, which often results in a tremendous splash as the iceberg strikes the water. If the water is deep, glaciers can calve underwater, causingthe iceberg to suddenly leap up out of the water.
Temperate glacier
A temperate glacier is at melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below freezing point from the surface to its base, although the surface snowpack may experience seasonal melting. A sub-polar glacier has both temperate and polar ice, depending on the depth beneaththe surface and position along the length of the glacier.
What happens with glaciers in global warming?
Hundred of glaciers an ice caps on every continent that global warming is severely affecting the water and glacial cycles of the planet. This is a profound change that unlike natural cycles like the Little Ice Age of the 16th and 17th centuries is proceeding very rapidly and appears tied to nonatural cycles. The best correlation for this change to all but a handful of the 160,000 land glaciers and parts of the great ice caps is to rising atmospheric temperatures tied to increasing amounts of greenhouse gases.
As more and more water reaches the ocean, it is increasing sea level at a faster rate --- which threatens every coastal city and shoreline. New scientific projections show at...
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