What is fast ice in the Arctic?
Fast ice (also called land-fast ice, landfast ice, and shore-fast ice) is sea ice that is “fastened” to the coastline, to the sea floor along shoals or to grounded icebergs. Fast ice may either grow in place from the sea water or by freezing pieces of drifting ice to the shore or other anchor sites.
Is there sea ice in the Arctic Ocean?
In the Arctic Ocean, the area covered by sea ice grows and shrinks over the course of the year. Each fall, as less sunlight reaches the Arctic and air temperatures begin to drop, additional sea ice forms. The total area covered by ice increases through the winter, usually reaching its maximum extent in early March.
Why is sea ice being lost rapidly in the Arctic Ocean?
The warming of the Atmosphere and the vertical heat fluxes from the Ocean are contributing to the Arctic sea ice rapid decline. A disappearance of Arctic sea ice in summer is predictable within 15 years.
Are there three kinds of ice in the Arctic Ocean?
Based on their sizes, they are given different names, such as growler and bergy bit. The other kind of ice is sea ice, also called pack ice. This kind of ice is formed by the freezing of seawater. In the central Arctic, the ice never thaws completely in summer, and thus it is known as multi-year ice.
What is fast sea ice?
Landfast ice (also called shore-fast ice) is a type of sea ice that primarily forms off the coasts in shallow water. In Antarctica, fast ice may also extend between grounded ice burgers. Unlike pack ice in deep water, landfast ice attaches itself to the coastlines or shallow sea floor on the continental shelves.
What is the meaning of fast ice?
ice that is anchored to the shore or ocean bottom, typically over shallow ocean shelves at continental margins; fast ice is defined by the fact that it does not move with the winds or currents. Note: This is land fast ice.
Where is sea ice found?
Sea ice is found in remote polar oceans. On average, sea ice covers about 25 million square kilometers (9,652,553 square miles) of the Earth, or about two-and-a-half times the area of Canada. Because most of us do not live in the polar regions, we may live for several decades and never see sea ice.
What is the loss of Arctic ice?
The continued loss of Arctic sea ice will include further Arctic warming, erosion of Arctic coastlines, and a disturbance of global weather patterns. Sea ice loss will also open up the Arctic to increased human activity, further disturbing Arctic communities and ecosystems.
Is the ice in the Arctic salty?
New ice is usually very salty because it contains concentrated droplets called brine that are trapped in pockets between the ice crystals, and so it would not make good drinking water. As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all of the brine is gone.
How does the Arctic sea ice form?
As the ocean water begins to freeze, small needle-like ice crystals called frazil form. Sheets of sea ice form when frazil crystals float to the surface, accumulate and bond together.
When does Arctic sea ice reach its maximum extent?
Arctic sea ice generally reaches its maximum extent each March and its minimum extent each September. This ice has historically ranged from roughly 14-16 million square kilometers (about 5.4-6.2 million square miles) in late winter to roughly 7 million square kilometers (about 2.7 million square miles) each September.
How does sea ice affect the polar environment?
Sea ice is frozen seawater that floats on the ocean surface. It forms in both the Arctic and the Antarctic in each hemisphere’s winter; it retreats in the summer, but does not completely disappear. This floating ice has a profound influence on the polar environment, influencing ocean circulation, weather, and regional climate.
When did NASA start tracking Arctic sea ice?
The Advanced Microwave Scanning Radiometer–for EOS (AMSR-E) on NASA’s Aqua satellite also contributed data (2002-2011), a record that was extended with the 2012 launch of the Advanced Microwave Scanning Radiometer 2 (AMSR2) on JAXA’s GCOM-W1 satellite. Reliable records of Arctic sea ice began in 1953]
How is the concentration of sea ice calculated?
Sea ice concentration is the percentage of each pixel that is covered by ice. Sea ice extent is calculated by adding up the pixels with an ice concentration of at least 15 percent. (NASA Earth Observatory image by Joshua Stevens and Robert Simmon, based on MODIS data.)