Presentation on theme: "TYPES OF ICE The ‘cryosphere’ refers to the places in the world where H 2 O is usually in the frozen state. This includes areas of snow, glaciers, sea."— Presentation transcript:
TYPES OF ICE The ‘cryosphere’ refers to the places in the world where H 2 O is usually in the frozen state. This includes areas of snow, glaciers, sea ice, and permafrost. These slides show photographs and images so that you can learn about different types of ice, and where these types are found. You can learn more about the cryosphere at this website:
Polar regions Most of the world’s ice is in the form of glacier ice and is found in the polar regions. 85% of the total area of the world covered in glacier ice is the Antarctic ice sheet. Greenland accounts for 11% of the area covered by glaciers. Glaciers in other parts of the Arctic and in high mountains of the world (e.g. Himalayas, Andes, Rockies, Alps) account for 4% of total glacier area. Key point: ‘glacier ice’ is not the same as snow, And not the same as frozen ocean (sea ice).
(http://www.climatechange.umaine.edu/Research/projects/Greenland/gr onland3d.jpg)http://www.climatechange.umaine.edu/Research/projects/Greenland/gr onland3d.jpg Antarctica (85% of all glacier ice cover on Earth, 13.5 mill km 2 ) Images of Antarctica and Greenland (not to scale) About 75% of the world’s freshwater is locked up in glacier ice! Images not compared to scale If all of the Antarctic ice sheet melted, sea level would rise by over 60 metres. You can check the effect of this on coastlines at this website:
On the Antarctic ice sheet, looking at the Transantarctic mountain range jpg?uselang=en-gbhttp://commons.wikimedia.org/wiki/File:NOAA_Royal_Society_Range. jpg?uselang=en-gb Michael Van Woert
Map showing the Transantarctic mountain range and location of Antarctica’s largest ice shelves ntarctic_Mountains.jpg?uselang=en-gb
At the edges of the Antarctic ice sheet (and parts of the Greenland ice sheet) glaciers reach the sea and float out over the water to form ice shelves. This is not the same as frozen sea water. NASA/Dick Ewers ice shelf
At the edges of the ice shelves chunks of glacier ice break off and float out to sea: these chunks of ice are called icebergs. They form by a process called ‘iceberg calving’. Ben Stephenson
Sea ice is completely different from an ice shelf. Sea ice forms as the top layer of the ocean freezes in winter. The area of sea ice in the Arctic Ocean and the Southern Ocean changes hugely with the seasons. Some sea ice in the coldest areas stays frozen all year. Brocken Inaglory Broken up sea ice, Ross Sea, Antarctica
This image shows more continuous sea ice. SC0781_% %29.jpg?uselang=en-gb
These images give a rough idea of the extent of winter sea ice in each hemisphere. s_animation.gif?uselang=en-gb Winter sea ice, N.H. e_february_ice-pack_ png Winter sea ice, S.H. To watch an animation of changing sea ice in the Northern Hemisphere follow this: c.png
In large parts of the Northern Hemisphere, there is frozen water in the ground. Areas are called ‘permafrost’ if ground remains below 0°C for at least two consecutive years. purple region : permafrost blue regions : seasonally frozen ground (the soil is frozen for 15 days or more per year) pink regions : intermittently frozen ground ( the soil is frozen for fewer than 15 days per year) solid line : the average maximum extent of the seasonal snow cover nground.gif?uselang=en-gb NASA modified image
Area of permafrost with ‘ice wedge polygons’ and thaw ponds on the ground’s surface (northern Canada). (Photo from an aeroplane.) ain)_in_Mackenzie_Delta_- _Viewed_from_Cessna_172_en_route_from_Inuvik_to_Tuktoyaktuk_- _Northwest_Territories_-_Canada.jpg?uselang=en-gbhttp://commons.wikimedia.org/wiki/File:Ice_Wedges_(Polygonal_Terr ain)_in_Mackenzie_Delta_- _Viewed_from_Cessna_172_en_route_from_Inuvik_to_Tuktoyaktuk_- _Northwest_Territories_-_Canada.jpg?uselang=en-gb Adam Jones
Mountain regions Snow, glaciers, frozen lakes, and permafrost are also found at high altitudes outside of the polar regions. This is because air temperature goes down as you gain altitude (go up) through the lower atmosphere. Because it is warmer near the equator, the closer you are to the equator, the higher a mountain has to be before the air is cold enough for snow patches and glaciers to form on it.
Latitude Height above sea level 5 km 0°0° 90° Global location of glaciers: latitude and altitude This graph gives a simple summary of how the altitude (height above sea level) where glaciers can form increases as you get closer to the equator. Equator North Pole Height at which snow can be found all year
Mt Kilimanjaro (Tanzania) is near the equator, reaches 5892 m above sea level (snow can survive the summer from approx m altitude) jaro_001.JPG
This NASA satellite image shows large areas of Asian mountains covered by glaciers NASA/Rupert Pupkin
Mt McKinley, Alaska The altitude of snow and glaciers is a lot lower than in the previous image of Mt Kilimanjaro because Alaska is much further from the equator.
Some high mountain ranges of the world with glaciers Himalayas Rockies Andes Alps Southern Alps (NZ)