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for those of you who have Mr. Albano as their science teacher.

Air Pressure

the pressure exerted by the weight of air

How is air pressure exerted?

in all directions

the air pressure pushing down on an object exactly balances________

the air pressure pushing up on the object

What is a barometer?

a device used for measuring air pressure

How does a barometer measure air pressure?

when air pressure increases, the mercury in the tube rises. When air pressure decreases, so does the height of the mercury column

What three factors combine to control wind?

pressure differences, the Coriolis effect, and friction.

what two terms have to do with pressure differences?

pressure gradient and isobars.

What is a pressure gradient?

the amount of pressure change occurring over a given distance.

What are isobars?

lines on a map that connect places of equal air pressure.

What do they indicate?

they indicate a steep pressure gradient and high winds.

Widely spaced isobars indicate_______

a weak pressure gradient and light winds.

Isobars where the air pressure number is the highest in the middle show______


Isobars that have the lowest air pressure number in the middle show_______


What is the Coriolis Effect

the Coriolis effect describes how Earth's rotation affects moving objects.

What happens in the northern hemisphere in the Coriolis Effect?

all free-moving objects or fluids are deflected to the right of their path of motion

and the southern hemisphere?

all free-moving objects or fluids are deflected to the left of their path of motion.

What is friction?

friction acts to slow air movement, which changes air direction.

What are jet streams?

fast moving "rivers of air

Jet streams travel in a ____ to _____ direction

east to west

Jet streams travel between ___ and ___ ____

120 and 240 kmph

What are cyclones?

centers of low pressure

What are anticyclones?

centers of high pressure

When the pressure gradient and the Coriolis effect are applied to pressure centers in the Northern Hemisphere_______

winds blow counterclockwise around a cyclone and clockwise around an anticyclone.

What happens in the southern hemisphere?

winds blow counterclockwise around an anticyclone and clockwise around a cyclone

In either hemisphere, friction causes a netflow of air inward around a(n)_____ and a net flow of air outward around a(n)______

1. cyclone 2. anticyclone

What is rising air associated with?

cloud formation and precipitation (rain, snow, sleet, hail, etc)

What is sinking air associated with?

clear skies

Low-Pressure centers (cyclones) produce_____

bad weather in any season

High-Pressure centers (anticyclones) produce____

nice (fair) weather in any season

What is the Non-Rotating earth model?

On a hypothetical non-rotating planet with a smooth surface of either all land or all water, two large thermally produced cells would form.

What are two important things to remember about the non-rotating earth model?

1. It is HYPOTHETICAL!!! 2. the earth would need to be made of ALL land or ALL water.

What is the problem with the non-rotating earth model

some areas would be freezing because of no sunlight and other areas would receive too much sunlight.

Name the 4 global wind types

trade winds, westerlies, easterlies, polar fronts

What is a polar front?

a stormy frontal zone separating cold air masses of polar origin from warm air masses of tropical origin.

What is a monsoon?

the seasonal reversal of wind direction associated especially with Asia.

In the winter, the wind blows from ____ to ___

land to sea

In the summer, the sea blows from ___ to ____

sea to land

What are local winds?

winds that are caused either by topographic effects (mountains, valleys, etc.) or by variations in surface composition (land and water) in the local area

What are land and sea breezes like in the day?

in coastal areas during the warm summer month, in the day the air moves from high pressure to low pressure. The high pressure is the water and the low pressure is the land. So in the day, wind moves from sea to land.

What are land and sea breezes like in the night?

the land cools faster than the water at night so the air moves to the warm water making the wind blow from land to sea at night.

What are valley and mountain breezes?

the air on the slopes of the mountain is heated more intensely than the air at the same elevation but at the valley floor. The air on the slopes is less dense so it glides up the slope and generates a valley breeze. The pattern may reverse after sunset.

What are prevailing winds?

winds that blow more often from one direction than from any other.

What is an anemometer?

an instrument that resembles a cup and is commonly used to measure wind speed.

What is El Niño?

the periodic warming of the ocean

Where does El Niño occur?

in the central and eastern Pacific

What happens at irregular intervals of three to seven years?

the warm countercurrents become unusually strong and replace normally cold offshore waters with warm equatorial waters.

What can a major El Niño cause?

Extreme weather in many parts of the world and the loss of many fish.

What is La Niña?

the name for when the temps. in the eastern pacific are colder than average.

La Niña has___

a distinctive set of weather patterns.

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