Air Pressure Test§ Flashcards
Why don’t we feel air pressure even though it is all around us
Because air pressure moves all around us
Briefly describe how an aneroid and Mercury barometer indicate air pressure
Both measure air pressure, it is measured in millibars, and in a Mercury barometer of the air pressure increases then the Mercury will rise
What is wind
Wind is the horizontal movement of air due to differences in air pressure
How is wind created
Wind is created by air(which acts like fluid) and moves away from one area of high pressure to an area with low pressure(H»L)
What is air pressure
Pressure exerted by the weight of the air above us
What are the three factors that control air
- pressure differences
- friction
- and the coriolis effect
Describe pressure difference
A greater pressure difference means greater wind speeds
Also called pressure gradien
Describe friction
This happens close to earths surface, friction slows air movement
Rugged terrain-(mountains) higher friction so slower wind
Smoot terrain-(ocean) lower friction so wind moves faster
Describe the coriolis effect
The earths rotation affects the movement of all fluid(like air). This affects wind direction only
What is a jet stream, which direction do they move
Jet streams are fast moving rivers of air near the tropopause, that run east to west parallel to isobars at high speeds of 75-150mph
What does the simple act of identifying pressure centers(low and high) tell you about weather in the areas of that pressure center
It allows us to predict the weather
What does a low pressure center predict
Cloudy and precipitation
What does a high pressure system predict
Clear skies and fair weather
In the north hemisphere what direction is the wind at a low
They blow counterclockwise at a low center
In the north hemisphere what direction does the wind blow at a high
They blow clockwise at a high center
What is the predominant force that determines these directions
The coriolis effect
In the Southern Hemisphere what direction does the wind blow at a low
They blow clockwise at a low center
In the Southern Hemisphere what direction does the wind blow at a high
They blow counterclockwise at a high center
Which is associated with stormy weather, rising or sinking air
Idk
What is global winds
It is winds that blow from a specific direction over long distances
How are global winds created
They are made by unequal heating of the earths surface leading to different pressure systems
How does the unequal heating of tropical and polar regions contribute to global winds
Tropical regions have more solar radiation received than radiated back to space, and polar regions have less solar radiation received than radiated back to space
What is local winds
They are winds that blow short distances and are produced by a locally generated pressure difference
How are wind direction and speed measured
An anemometer measures wind speed, and a wind vane indicates wind direction
