Category Sea/Ocean

What are the specialities of the Pacific Ocean?

Occupying about one-third of the surface of the planet, the Pacific Ocean is the largest ocean on earth. It lies between the continents of Asia and Australia on the west and is bordered by North America and South America on the east. It covers an area of 161.76 million square kilometres without counting in the South China Sea. It has double the area and more than double the water volume of the next largest water-body, the Atlantic Ocean. It covers more area than the total land surface of the globe.

The Pacific Ocean meets the Arctic Ocean in the Bering Sea in the Northern Hemisphere and in the Southern Hemisphere, it mixes with the Atlantic Ocean in the Drake Passage between Tierra del Fuego in South America and Graham Land in Antarctica.

One cannot clearly say where the Pacific and Indian oceans become separate, but a line of islands extending eastward from Sumatra, through Java to Timor, extending across the Timor Sea to Cape Londonderry in Australia is usually considered as the points of separation of the two. The deepest point in the Pacific Ocean is in the Mariana Trench. It is located in the western Pacific located around 200 kilometres east of the Mariana Islands to the east of the Philippines.

The Pacific Ocean Basin also contains 75 per cent of the world’s volcanoes and forms the Ring of Fire, which is a ring of Pacific Ocean volcanoes around the ocean basin. There is also an interesting story behind the name of this ocean.

It was Ferdinand Magellan, who gave the name Pacific inspired from the Latin word ‘pacificus’ meaning ‘tranquil.’ It is said that he felt the ocean to be unusually calm as he entered its waters and this led to the name.

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WHAT BRINGS ABOUT THE END OF AN ICE AGE?

The rotation and revolution of Earth, the amount of solar radiation and the amount of carbon dioxide in the atmosphere are all factors that contribute to a warming up of Earth, which ends an ice age. Changes in ocean currents also have a major effect on temperatures on Earth.

Over thousands of years, the amount of sunshine reaching Earth changes by quite a lot, particularly in the northern latitudes, the area near and around the North Pole. When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice, starting an ice age. When more sunlight reaches the northern latitudes, temperatures rise, ice sheets melt, and the ice age ends.

Credit: American Museum of Natural History

Picture credit: Google

WHAT ARE THE LARGEST BODIES OF ICE IN THE WORLD?

In today’s world, the ice sheets of Antarctica and Greenland. An ice sheet is a continuous mass of ice covering more than 50,000 km2. The ice sheet in Antarctica covers 14 million km2. It is 1.6 to 6.4 km thick and holds 30 million km2 of ice. The Greenland ice sheet covers about 1.7 million km2.

The Antarctic ice sheet is the largest block of ice on Earth. It covers more than 14 million square kilometers (5.4 million square miles) and contains about 30 million cubic kilometers (7.2 million cubic miles) of water.

The Antarctic ice sheet is about 2 kilometers (1.2 miles) thick. If it melted, sea level would rise by about 60 meters (200 feet).

The Greenland ice sheet is much smaller than the Antarctic Ice sheet, only about 1.7 million square kilometers (656,000 square miles). It is still the second-largest body of ice on the planet.

The Greenland ice sheet interacts much more dynamically with the ocean than the Antarctic ice sheet. The annual snow accumulation rate is more than double that of Antarctica. Glacial melt happens across about half of the Greenland ice sheet, whereas it is much more isolated on the far western part of Antarctica. Greenland’s ice shelves break up much faster than those surrounding Antarctica.

Both the Antarctic and Greenland ice sheets have caused the land under them to sink. Eastern Antarctica is about 2.5 kilometers (1.6 miles) below sea level because of the colossal weight of the ice sheet above it.

Credit: National Geographic

Picture credit: Google

IS ANTARCTICA A DESERT?

A desert is defined by the amount of precipitation (rain, snow, mist and fog) in an area. A region that receives very little precipitation is classified as a desert. There are many types of deserts, including subtropical, coastal and polar deserts. What they all have in common is a barren, windswept landscape, which makes it difficult for plants and animals alike to gain a foothold on land. This all certainly applies to Antarctica.

The average yearly rainfall at the South Pole over the past 30 years was a tiny 10 mm (0.4 in). Most of the continent is covered by ice fields carved by the wind, and craggy mountains covered in glaciers. While Antarctica is home to wonderful forests of low-lying mosses and lichens, there are only two flowering plants that can survive the harsh conditions. And most of the animals we encounter – penguins, seals, whales and seabirds – rely on seafood for sustenance.

Credit: aurora expeditions

 

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HOW OLD IS GLACIER ICE?

  • The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old
  • The age of the oldest glacier ice in Greenland is more than 100,000 years old
  • The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old.

Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100 years or less. Based on flow rates, it takes less than 400 years for ice to transit the entire 140 + mile length of Bering Glacier, Alaska’s largest and longest glacier.

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HOW MUCH OF THE WORLD IS COVERED BY ICE?

Almost 10 per cent of Earth’s total landmass is covered by ice. This includes glaciers, Ice caps and ice sheets. Glaciers cover 15 million km2. During the last ice age, 32 per cent of the total land area was covered by ice.

Most of the Earth’s ice that we see is to be found in large masses of “nearly” pure ice: ice-sheets and glaciers of various types, ice shelves and sea ice packs. It is quite easy to calculate the surface of the areas covered with ice: it has been calculated that this amounts to approximately 15 million km2, equal to one tenth of the surface of the Earth’s emersed land. It is more difficult, on the contrary, to calculate the volume of ice because the thickness of the entire covered area must be known: using special techniques it is possible to measure the ice thickness in various points of a glacier and therefore to estimate the volume. For example the average thickness of the Antarctic sheet is 2,100 m, with peaks of 4,800 m in Land of Wilkes, in the Eastern sector: with a surface of little less than 13,600,000 km2, the total volume of the Antarctic ice is 30 million km3.

Credit: Energy & environment

Picture credit: Google