the pressure exerted by the weight of air above
of the various elements of weather and climate, changes in _______ _______________ are the least noticeable
a column of air 1 square inch in cross section, measured from sea level to the top of the atmosphere would way 14.7 pounds and is referred to as...
(down, up, sideways)
air pressure is exerted in ________ direction
our body is made to withstand ________________
1 kilogram per square centimeter
14.7 lbs per square inch
air pressure at sea level is about
move freely around the space provided to them
the atmosphere is confined from below by _____________ and from above by ______________
what is the force exerted against a surface by the continuous collision of gas molecules
An instrument that measures changes in air pressure, consisting of a glass tube partially filled with mercury, with its open end resting in a dish of mercury.
Metric unit of atmospheric pressure
standard sea level pressure
inches of mercury
media use _______ ____ _________ to describe atmospheric pressure
Torricelli (galileo's student)
invented the barometer
a vast ocean of air that exerts pressure on us and all objects around us ( according torricelli )
when air pressure increases mercury _______
29.92 inches of mercury
standard atmospheric pressure at sea level equals ___________ inches of mercury
A smaller instrument that measures changes in air pressure without using a liquid.
an aneroid barometer uses a partially evacuated ______________ ___________
current air pressure
the ______________________________ is more important than the current pressure reading
Cloudiness and precipitation
falling pressure is often associated with increasing ________________ and possibility of __________________
rising air pressure generally indicates _____________ ______________
increasing cloudiness and possibility of precipitation
falling pressure is associated with...
rising pressure is associated with...
An instrument that continuously records air pressure changes over time
The horizontal movement of air from an area of high pressure to an area of lower pressure
___________________ __________________is the ultimate energy source for most wind
1. pressure gradient force
2. coriolis effect
because earth rotates, wind is controlled by
air moves from a place of ______ pressure to a place of ________ pressure
Lines joining places on the map that have the same air pressure
the amount of pressure change occurring over a given distance / pressure gradient
the spacing of isobars indicates...
the amount of pressure change occurring over a given distance
steep pressure gradient and high winds
Closely spaced isobars indicate
weak pressure gradient and light winds
Widely spaced isobars indicate
right angle isobars
the pressure gradient force is always directed at ________ ________ the the isobars
by converting all pressure measurements to sea level equivalents
how is pressure compensation for high elevations accomplished?
wind arrow shafts
on a weather map, wind direction is shown as ____________ __________ __________ and speed is shown as ______ _________
horizontal pressure gradient
what is the driving force of wind?
The effect of Earth's rotation on the direction of winds and currents.
all free moving objects or fluids (including wind) are deflected to the _________ in the Northern hemisphere and to the ____________ in the Southern hemisphere
1. deflection is always directed at right angles to the direction of airflow
2. affects only wind direction not speed
3. is affected by wind speed (the stronger the wind the greater the deflection)
4. is strongest at the poles and weakens toward the equat
the effect of wind is important only within a ______________________ of earthys surface
what acts to slow air movement and as a consequence alters wind directions?
the faster the wind speed the greater the _____________.
A wind usually above a height of 600 meters that blows parallel to the isobars and at higher speeds than surface winds.
bands of high-speed winds about 10 kilometers above Earth's surface
the most prominent features of upper level air flow are...
________ lowers the wind speed, so it reduces the coriolis effect
over smooth ocean terrain, friction is _______
over rugged terrain, friction is ________
centers of low atmospheric pressure
high pressure centers of dry air
in a low pressure cyclone, the values of the isobars ______________ as they move toward the center
in high pressure anticyclones, the value of the isobars _________ as they move toward the center
inward and counterclockwise
in the NH, in a low pressure system, winds blow ___________ and ____________
outward and clockwise
in the NH, in a high pressure system, winds blow ___________ and ____________
the coriolis effect deflects winds to the _________ in the NH and to the _________ in the SH
a net inflow around a cyclone
a net outflow around an anticyclone
what produces clear skies?
what is associated with cloud formation and precipitation?
the net inward transport of air causing a shrinking of the area occupied by the air mass
Barometric Tendency (Pressure)
the change of atmospheric pressure during the last few (generally three) hours before a regular observation.
when air ______________ ________________is must pile up (increase in height to allow for the decreased area in now occupies
exerts less pressure than that occurring in surrounding regions
a surface low can only exist as long as the column of air ____________________________________________________________________________.
net accumulation of air
a low pressure center causes a _________________________________, which increases its pressure
at some layer aloft
in a low pressure cyclone, for a surface low to exist for very long, a compensation must occur _________________________________________.
in a low pressure cyclone, surface convergence could be maintained if _____________ aloft occured at a rate _________ to the inflow below
in a low pressure cyclone, __________________ aloft can intensify a storm or maintain them
winds that blow in at the surface
a belt of low pressure lying near the equator and between the subtropical highs
the equatorial low is marked by ______________ _______________
unstable conditions and stormy weather
because rising air often results in cloud formation and precipitation, a low pressure center is generally related to __________________ _________________ and _______________ ________________
because descending air is compressed and warmed, cloud formation and precipitation is unlikely in a(n) ____________________
west to east
low pressure cyclones move _______ to ______ and last for about __________
the underlying cause of wind is ___________ ___________ of the earths surface
the atmosphere acts as a giant heat transfer system, moving __________ air poleward and __________ air equatorward
on a nonrotating earth,the heated equatorial air would rise until it reaches the ____________ , which acts like a lid and deflects air _____________.
eventually, this upper level airflow would reach the _________, _________, _________ __________ in all di
this hypothetical circulation system of the nonrotating earth has upper level air flowing _____________ and surface air flowing _____________
Intertropical Convergence Zone (ITCZ)
a low pressure zone where winds from the north and south converge
A belt of high pressure located at approximately 30o N and 30o S, which pushes heavy subsiding air outward toward both north and south.
Prevailing winds that blow northeast from 30 degrees north latitude to the equator and that blow southeast from 30 degrees south latitude to the equator
Dominant winds of the mid-latitudes. These winds move from the subtropical highs to the subpolar lows from west to east.
the steep temperature gradient across the middle latitudes in the winter months corresponds to a __________ flow aloft
in the winter the jet stream moves _______
in the summer the jet stream moves ________
the Northern Hemisphere is rainy in the _______________
the Southern Hemisphere is rainy in the
Prevailing winds that blow from east to west between 60degrees-90degrees latitude in both hemisphere.
a low pressure area formed sixty degrees N when the prevailing westerlies rise above the polar easterlies
boundary at which cold polar air meets the warmer air (causes a stormy belt) of the middle latitudes
The source region for the variable polar easterlies
subtropical and polar highs
the __________ and _____________________ are areas of subsiding air that flows outward at the surface, producing the prevailing winds
equatorial and subtropical
the low pressure zones of the _________________ and __________________ regions are associated with inward and upward accompanied by clouds and precipitation
subpolar low in the southern hemisphere
the only true and continuous pressure belt is the ______________ in the ______________________________ where the ocean is interrupted by land masses
in the Northern Hemisphere, land masses break up the ocean surface and large _______________ _______________ disrupt the pattern
the circulation over the oceans is dominated by semi permanent cells of _________ pressure in the subtropics and cells of _______ pressure over the subpolar regions
Trade winds and westerlies
subtropical highs are responsible for the
seasonal wind patterns that cause wet and dry seasons
summer monsoons are _____
winter monsoon are ______
the general circulation is produced by semipermanent cells of high and low pressure over the ________ and is complicated by seasonal pressure changes over _________
small scale winds produced by a locally generated pressure gradient
topographic effects or variations in surface composition - land and water
local winds are caused by _____________________________________ or _____________________________ in the immediate area
movement of air from sea to land during the day when cooler air from above the water moves over the land, forcing the heated, less dense air above the land to rise
mid to late afternoon
Sea breeze is most intense at
movement of air from land to sea at night, created when cooler, denser air from the land forces up warmer air over the sea
in coastal areas during the summer months, _______ is heated most intensely during the daylight hours
The movement of air created by warm air rising and flowing up the slope of a mountain.
the air along the slopes of the mountains is heated ________ intensely than the air at the same elevation over the valley floor
The movement of air caused by cool air sinking and moving down the slope of a mountain.
next to the ground
rapid radiation cooling along the mountain slopes produces a layer of cooler air _________ _____ ______ __________
Valley breezes are most common during the ________ seasons
Mountain breezes are more common in the ________ season
dry warm wind moving down on the eastern slopes of the Rocky Mountains; occurs when a strong pressure gradient develops in a mountainous region
because condensation may have occurred as the air ascended the windward aside, releasing latent heat, the air descending the leeward slope will be _________ and _________ than it was at a similar elevation on the windward side
a very dry and often dusty wind that blows in Southern California that puts it at risk for fires
A cloth cone open at both ends mounted in a high place to show which direction the wind is blowing
ther direction in which they blow
winds are always labeled by ...
Instrument used to measure wind direction
(has a dial of N,S,E,W or 0 to 360)
winds are always labeled by the _________ from where they blow
a wind vane always points ________ the wind
An instrument used to measure wind speed
winds that consistently blow in the same direction over large areas of Earth
what wind dominates the midlatitudes and move weather from west to east?
(oceanography) a warm ocean current that flows along the equator from the date line and south off the coast of Ecuador at Christmas time
during an el nino, strong equatorial countercurrents amass large quantities of ___________ than normal water along the west coast of South America
during a la nina, it has ___________ than normal water along the central and eastern pacific
cold nutrient water
The warm water and and associated low pressure arid areas of Peru and Chili to receive unusually ________ _______that can lead to _________ ___________ and the blocking of _________ __________ ________ needed by fish to survive.
2 to 7
9 months to 2
an el ni�o may happen in intervals of ___ to ____ years and usually persist or spans of ____ months to ____ years
A cooling of the ocean surface off the western coast of South America, occurring periodically every 4 to 12 years and affecting Pacific and other weather patterns.
upwelling of deep nutrient rich water
during a la nina, the cold Peru current that flows equatorward along the coast of Chili and Peru intensifies, which encourages ___________________________________________
one major benefit of El nino is a lower than normal average number of ___________- ___________
one major deficit of la nina is more frequent _______________
south america; from ecuador to peru
Where does the el nino current flow?
south america; from australia to indonesia
where does the la nina current flow?
1. winter temperatures are warmer than normal
2. wetter winters in the North america southwest and Mexico northwest
3. wetter and cooler conditions in southeast US
4. lower than average number of Atlantic hurricanes
what is the result of an el nino in North America?
1. cooler and wetter conditions over the northwestern US
2. cold winter temperatures in the Northern plain states
3. unusually warm conditions occur in the southwest and southeast
4. in the western pacific they experience wetter than normal temps
what is the result of an la nina in North America?
the atmospheric pressure conditions corresponding to the periodic warming of El Nino and cooling of La Nina.
A linkage between weather changes occurring in widely separated regions of the world.
Each time an el nino occurs barometric pressure _______ over large portions of the eastern Pacific and ______ in the tropical potions of the western pacific
swings back in the opposite direction
As an el nino comes to an end the pressure difference ___________________________________________ triggering a la nina
climate predictions for distant locations
understanding teleconnection patterns allow meteorologists to make _____________________________
national weather service predictions for periods from 1 to 13 months into the future are called climate outlooks
relatively dry conditions
regions influenced by high pressure, with its associated subsidence and diverging winds experience...
regions under the influence of low pressure and its converging winds and ascending air experience...
areas dominated by subtropical high pressure cells receive much _____________ amounts of precipitaton
the warm humid trade winds converge to yield abundant _________ throughout the year
cold air has a ______ capacity for moisture with warm air
2. wind belts
3. water capacity
4. distribution of land and water
5. mountain barriers
what affects global precipitation?