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77 terms

Ch 19 Air Pressure and Wind Everything

this combines all the terms in the past 3 sets
air pressure
is the force exerted by the weight of air above
What is exerted upward, downward, and sideways ?
air pressure
What pushes down on an object and exactly balances it pushing up on the object?
air pressure
What flows from areas of higher pressure to areas of lower pressure?
air pressure
sea level pressure
this standard is 1013.2 millibars
mercury barometer
when air pressure increases, the mercury in the tube rises; invented by Torricelli
lines on a map that connect points of equal pressure
the principal cause for variations in air pressure from place to place
What is the ultimate energy source for most wind
solar radiation
What is the force that generates winds?
pressure differences
The Corolis effect, friction, and pressure gradients(differences) all influence or control what?
steep pressure gradient
produces strong winds
Coriolis effect
influences wind direction, the stronger the wind, the greater the deflection of the Corolis effect
What causes the deflection of wind due to it is strongest at the poles?
Corolis effect
jet streams
high-altitude, high-velocity"rivers" of air
low-pressure systems - N.Hemisphere
winds blow counterclockwise toward the center
low-pressure systems - S. Hemisphere
winds blow clockwise toward the center.
low-pressure systems
general movement across the US is from west to east
high-pressure systems
Northern Hemisphere - the winds blow clockwise outward from the center
Air subsides in the center of this
high-pressure systems
What is associated with descending air, clear weather, & relatively dry conditions
high-pressure systems
continuous pressure belt
located in the Southern Hemisphere because there are no landmasses to interrupt that pressure belt
centers of low pressure
value of the isobars increase from the outside toward the center
causes a net flow of air inward around a cyclone and outward around an anticyclone
seasonal changes in wind direction associated with large landmasses and adjacent water bodies; occur during summer in India
subtropical high
an example of this is the deserts of the Sahara and the deserts of Australia
equilateral low
a pressure zone associated with rising air near the equator
are labeled according to the direction from which they blow
local winds
caused by topographical or variations in surface composition in the immediate area
valley breeze
generated because the warmer air on the mountains is less dense and glides up along the slope generating a breeze
mountain breeze
examples of local winds; after sunset in mountainous areas, cold air moves downslope into the valley
sea breeze
usually originates during the day and flows toward the land
What is most intense during mid to late afternoon ?
sea breezes
land breeze
usually originates during the evening and flows toward the water
prevailing winds
winds that consistently blow more often from one direction than from any other
prevailing westerlies
move weather across the US from west to east
instrument that is used to measure wind speed
La Niña
phenomenon associated with surface temperatures in the eastern Pacific that are colder than average
El Niño
phenomenon associated with surface temperature in the eastern Pacific that are warmer than average
Closely spaced "what" indicate high winds?
Widely spaced "what" indicates light winds
What deflects all free- moving objects to the right of their path of motion in the Northern Hemisphere?
Corolis effect
If the Earth didn't rotate then the air at the equator would rise and move toward the poles. What is this called?
equatorial low
Where does the land heat up more during the daylight hours than does the adjacent body of water?
In coastal areas during the summer
What can impact the fishing industry, climate and the farming industry?
El Nino
What is the opposite of El Nino
La Nina
What happens at irregular intervals of 3 to 7 years?
El Nino
What is the weather that accompanies a drop in barometric pressure?
bad weather
What is the weather that accompanies a rise in barometric pressure
good weather
What causes wind?
Wind is the result of horizontal differences in air pressure. Air flows from areas of higher pressure to areas of lower pressure.
What is the energy source for most wind?
Solar radiation
What generates pressure differences?
the unequal heating of the Earth's surface
What are the factors that control wind?
pressure differences, the Corolis effect, and friction
What are isobars?
are lines on a map that connect places of equal air pressure.
What does the spacing of isobars indicate?
it shows the amount of pressure change occurring over a given distance
A steep pressure gradient causes what?
a greater acceleration of a parcel of air
What do closely spaced isobars indicate?
that there is a steep pressure gradient and high winds
What do widely spaced isobars indicate?
that there is a weal pressure gradient and light winds
What is the driving force of wind?
the pressure gradient, which has both magnitude and direction
What does friction affect?
Wind speed and direction
What does the Coriolis effect affect?
Wind direction only
air pressure
the force exerted by the weight of the column of air above a given point
an instrument that measures barometric pressure
pressure gradient
the amount of pressure change occurring over a given distance
Corolis effect
the apparent deflective force of Earth's rotation on all free-moving objects, including the atmosphere and oceans; Deflection is to the right in the N. Hemisphere and to the left in the S. Hemisphere
jet stream
swift (12-240 km/hr), high altitude winds
a low-pressure center characterized by a counterclockwise flow of air in the Northern Hemisphere
a high-pressure center characterized by a clockwise flow of air in the Northern Hamisphere
the dominant west-to-east motion of the atmosphere that characterizes the regions on the poleward side of the subtropical highs
prevailing wind
a wind that consistently blows from one direction more than from another
an instrument used to determine wind speed
El Nino
the name given to the periodic warming of the ocean that occurs in the central and Eastern Pacific; A major El Nino episode can cause extreme weather in many parts of the world
trade winds
two belts of winds that blow almost constantly from easterly directions and are located on the north and south side of the subtropical highs
polar easterlies
in the global pattern of prevailing winds that blow from the polar high toward the subpolar low; These winds, however, should not be thought of as persistent winds, such as trade winds
polar front
the stormy frontal zone separating cold air masses of polar origin from warm air masses of tropical origin
seasonal reversal of wind direction associated with large continents, especially Asia; In winter, the wind blows from land to sea.In summer, the wind blows from sea to land