Atmospheric and Oceanic Interactions

the force of air on a surface

Air pressure

Air pressure is caused by the weight of all the molecules that make up the air.

- the combined force of air on just 1 square foot of surface, is about a ton!

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a high pressure system usually brings cooler temperatures and clear skies.

a low pressure system usually brings warmer weather, storms and rain.

the curving of moving objects, including wind, from a straight path due to Earth’s rotation

Coriolis Effect

The Coriolis effect causes wind and ocean surface currents to curve to the right north of the equator, and left south of the equator.

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There is an old urban myth that the Coriolis effect causes water going down drains or toilets to turn different directions above and below the equator?

This myth is false! The Coriolis effect doesn’t influence such small bodies of water.

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a large body of air that is similar in temperature, humidity, and air pressure throughout

Air Mass

Air masses are categorized by temperature and moisture.

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When two different air masses meet, the boundary is called a “front” – there are 4 basic types.

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the vertical circular motion of a fluid (such as air) in which hot material rises while cold material sinks

Convection Current

Convection currents can happen in any material that flows, liquid or gas –Earth’s mantleAtmosphereOceansAnd lava lamps!!!

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Convection currents happen because heating and cooling changes density Heating

decreases density; less dense material floats.

Cooling increases density; more dense material sinks.

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a wind that blows from the land to the sea at night

Land Breeze

The air over the ocean stays warm longer than the air over the land, after the Sun goes down?

This causes convection currents that create land breezes blowing toward the ocean at night.

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a wind that blows from the sea to the land during the day

Sea Breeze

On a hot, sunny day the temperature of the sea hardly changes but the land heats up quickly.

This causes the light breezes to blow toward land instead, making sea breezes.

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instrument used to measure the humidity of air

Psychrometer

Hotter air can hold more water, generally.

Since your sweat can’t evaporate to cool you as quickly if humidity is high, it feels even HOTTER!

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The most humid state in the United States is Washington.

The most humid regions of the world are coastal areas near the equator, like Thailand and India.

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wind that blows predominantly from a single direction

Prevailing Winds

If it wasn’t for the trade winds, America might not exist! in the 18th

century, ships used them to cross the Atlantic Ocean.

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instrument that records wind speed and direction

Anemometer

The first anemometer was invented in 1450 by an Italian architect, Battista Alberti.

He was called the “prophet” of the Renaissance.

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currents formed when cold air temperatures and high salinity (salt) of surface currents make water denser, causing it to sink to the bottom; thus resulting in movement

Deep Currents

The ocean has three temperature layers.

1.  The surface, temperatures vary 0-30 deg C. 

2.  The thermocline, temperatures decrease with depth. 

3.  The deep layer is below 1000 m, the temperature is near 0– 5 deg C  and there is no seasonal change.

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Changes in deep currents can slow the global currents enough to cause “mini-ice ages”.

1350-1850; scientists call it the “Little Ice Age” and it affected climate all over the world.

Some scientists think it may be happening, again.

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water movement 3-10 ft below the surface nearshore and 33 ft in deep ocean areas

Surface Currents

Surface and deep water currents connect the currents in all of Earth’s oceans, in a giant “Global Conveyor Belt”

This means that what happens in one ocean, affects all of the world’s oceans.

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warm ocean current flowing Northeastwards off the Atlantic Coast of the U.S. from the Gulf of Mexico

Gulf Stream

The warm waters of the Gulf Stream make it possible for some areas of Northern Europe have milder climates than places just as far north in Canada.

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a large, rotating tropical storm with wind speeds of at least 74 mph

Hurricane

Hurricanes lose strength when they go on land or into cold waters, so they usually form in oceans near the equator.

They need warm waters to provide energy for the storm.

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Every second, a large hurricane can release the energy of 10 atomic bombs.

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