Earth Cycles - SOS Playlist


Earth Cycles Playlist Companion Document

day_night.jpgDay Night Terminator during course of one DAY

This shows the day night cycle over the course of a day.  It is due to the rotation of the Earth on its axis.
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day_night_06z.jpgDay Night Terminator over course of a YEAR

Because the Earth is tilted 23.5 º, different parts of the Earth are illuminated at different times of the year.  This causes the seasons.  For instance in July, the north pole is complete lit (24hr days) and the south pole is complete dark (24hr nights.)  In March, the terminator (day/night boundary) goes straight through the north and south poles and everywhere on Earth has a 12 hour day.  This is called the equinox.
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weekly_sea_ice.jpgSea Ice over course of a YEAR

This shows how the ice at the north and south poles expands and contracts over the course of a year.  For example, in December, when there is no sunlight hitting the north pole, the northern icecap is at its largest.  And, at the same time, the south pole is receiving light from the Sun, so its icecap is at its smallest.
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Solar Isolation.jpgSolar Insolation over course of a YEAR

This shows how different parts of the Earth receive different amounts of energy from the Sun at different times of year.  Yellow represents the hottest and red is cooler.  For example in July, the northern half of the Earth receives more sunlight than the southern half.
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Land-SeaSurfaceTemp.jpgTemperature on Sea and Land over course of a YEAR

This shows how the Sun heats the Earth over the course of a year.  The dark brown represents the most direct sunlight and the warmest temperatures.  You can see how this dark brown moves across the Earth's surface (from East to West) because of the rotation of the Earth. A good place to look is Africa because the pattern of heating is clear in the Sahara Desert.
Precipitation.jpgRainfall over course of a YEAR

This shows seasonal changes in rainfall patterns. Look at India and note the effects of the annual monsoon shown in red. Areas with well-defined rainy seasons show up clearly. Africa presents a good example of an area with distinct rainy seasons. The interplay of seasonal temperature changes and wind circulation patterns are largely responsible for these patterns. In these areas the annual seasonal cycles are reflected in rainfall.
Vegetation.jpgVegetation over course of a YEAR

In this visualization, green represents vegetation and brown is where it is dry.  You can see that during the summer many places become more green.  You can see the yearly cycle of vegetation as the growing season changes in different parts of the Earth. Africa again presents a good template to see these changes especially in the southern portion of the Sahara Desert where annual changes in temperature and rainfall strongly affect vegetation growth. Another good place to watch seasonal patterns of change is Australia where the generally dry landmass shows a seasonal bloom.
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sea_surface.jpgSea Surface Temperature over course of a YEAR

As the Earth goes through different seasons the ocean temperature change.  During the summer the ocean is warmer than during the winter.  You can see how the bands of warmer water move up and down from North to South as the seasons change.  For example if you look at the New York region, you can see how the water temperature changes during the course of a year.
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loggerhead.jpgLoggerhead Turtle habitat over course of a YEAR

Animals like certain temperatures of water to live in.  For example, Loggerhead Turtles, shown here, like to keep in relatively warm (but not too warm) water, shown by the green zone.  As the green zone moves north and south during the year, due to the change in seasons, the turtles also move north and south to stay in the water temperature that they like.
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animal_tracking.jpgMigration of Shearwater and Elephant Seals over course of a YEAR

One yearly cycle of the Earth that you might not think of is how animals migrate.  In this visualization, the Shearwater (birds) go back and forth from New Zealand to Japan and the Aleutian Islands in the Northern summer, then back to New Zealand for the Northern Winter (which is New Zealand's summer.)  The Elephant Seals migrate twice during the course of a year.  Once post breeding and once post molting (shedding of winter fur).
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