SEA ICE

1. What Is Sea Ice Sea Ice Facts SEA ICE Sea Ice Cycle Learn About Sea Ice Why Is Arctic Sea Ice Important Difference Between Arctic And Antarctica Sea Ice

2. Sea Ice Facts • Sea ice is frozen sea water that forms in the Arctic ocean in the northern hemisphere, and in the southern ocean surrounding Antarctica in the southern hemisphere. • The formation of sea ice each year plays a major role in the global climate system, by driving vertical ocean circulation that helps to redistribute heat between the equator and the polar regions. • Sea ice is fresher than the sea water from which it forms. It is the salt that is "excluded" from the sea ice that makes the surface waters of the ocean more dense, causing the overturning circulation. • Sea ice is also highly reflective, so when it forms it reduces the amount of solar radiation absorbed by the ocean.

3. What Is Sea Ice • Sea ice is similar to icebergs. Sea ice is formed from ocean water that freezes. Because the oceans consist of saltwater.In polar regions the surface of the sea freezes, due to the low air and water temperatures: the product is known as ‘sea ice’. It exists year-round in the central Arctic and in some Antarctic bays, extending in winter across the entire Arctic and far out to sea around Antarctica. As ice crystals form from sea water, so salt is excluded and eventually returned to the sea. Sea ice therefore contains no salt, except where pockets of sea water become trapped in the ice.

4. Why Is Sea Ice Important • Arctic sea ice keeps the polar regions cool and helps moderate global climate. Sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. As sea ice melts in the summer, it exposes the dark ocean surface. Instead of reflecting 80 percent of the sunlight, the ocean absorbs 90 percent of the sunlight. The oceans heat up, and Arctic temperatures rise further. • A small temperature increase at the poles leads to still greater warming over time, making the poles the most sensitive regions to climate change on Earth. According to scientific measurements, both the thickness and extent of summer sea ice in the Arctic have shown a dramatic decline over the past thirty years. This is consisistent with observations of a warming Arctic. The loss of sea ice also has the potential to accelerate global warming trends and to change climate patterns.

5. Sea Ice Cycle • EvaporationThe evaporation of a water surface goes on continually under favourable conditions. It requires heat, and the heat is taken from the water itself, thus lowering its temperature. The amount of heat loss due to evaporation depends on several factors including the wind speed, relative humidity near the water surface, and the temperature difference between air and water. • ConductionThe process by which heat is transferred from the ocean to the atmosphere through the movement of particle is known as conduction. When warm air is in contact with the cold ocean water, heat is transferred from the air to the water; heat will be conducted down into the ocean. When the water is warmer, heat is transferred from the water to the air; heat will be conducted away from the ocean. • ConvectionConvection also plays a part in assisting the transfer of heat away from the ocean surface because when the air near the warm ocean gets heated, it expands, rises and carries heat away from the ocean

6. Difference Between Arctic And Antarctica Ocean • Because the Arctic Ocean is mostly covered by ice and surrounded by land, precipitation is relatively rare. Snowfall tends to be low, except near the ice edge. Antarctica, however, is entirely surrounded by ocean, so moisture is more readily available. Antarctic sea ice tends to be covered by thicker snow, which may accumulate to the point that the weight of snow pushes the ice below sea level, causing the snow to become flooded by salty ocean waters

7. Is Sea Ice the same as Icebergs • No Icebergs are broken pieces of glaciers which originate from masses of snowfall on land.Glaciers carry sediment around with them as they move, and these sediments can be studied to determine where the glacier or iceberg originated.