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Meteorology exam 3

Terms in this set (67)

Newton's Laws of Motion
1. an object in motion (or at rest) tends to stay in motion (or at rest) until acted upon by an outside force
3. for every action there is an equal and opposite reaction
what does warm temperature mean for surface pressure? Cold temp?
warm temp = low surface pressure;
cold = high surface pressure
how does humidity affect surface pressure? (high and low humidity)
high humidity = low surface pressure
low humidity (dry air) = high surface pressure
what is the primary difference between surface level charts and upper level charts
surface level uses isobars
upper level uses height contour lines to show ridges and troughs
is it colder or warmer in ridges or troughs
troughs are cold, ridges are warm
zonal vs. meridional circulation
zonal circulation occurs along latitudinal lines
meridional occurs along longitudinal lines
pressure gradient force
horizontal difference in pressure, which causes wind
Coriolis effect
The effect of Earth's rotation on the direction of winds and currents.
centripetal force
circular motion when pressure gradient force and coriolis force are out of balance (called geostrophic wind in upper levels)
wind blows from ____ pressure areas to ____ pressure areas
high; low
air flowing in is ____ and air flowing out is ____
convergence; divergence
atmospheric pressure decreases most rapidly with elevation in a ___ ____ of air
cold column
___ air aloft is associated with low atmospheric pressure, and ___ air aloft is associated with high pressure
cold; warm
what instrument measures air pressure
barometer
the amount of pressure change that occurs over a given horizontal distance is the _______
pressure gradient
on a weather map, closely spaced isobars indicate what? and widely spaced isobars?
a steep pressure gradient, strong PGF and high winds; the opposite for widely spaced isobars
the Coriolis force cause the wind to bend to the ___ in the Northern hemisphere and to the ___ in the Southern
right; left
the Coriolis force only influences the
A. direction or
B. speed of the wind?
direction
the Coriolis force increases as what two factors also increase
latitude and wind speed
above the middle and high latitudes, the winds on an upper level chart then to blow ____ to contour lines (isobars) in a more or less west-to-east direction in both hemispheres
parellel
sinking air occurs above a surface ____-pressure area, and rising air occurs above a surface ____-pressure area
high; low
in the Northern hemisphere surface winds blow ________ and ______ form the center of a high, and _______ and _______ toward the center of a low
clockwise and outward; counterclockwise and inward
in the Southern hemisphere surface winds blow ________ and ______ form the center of a high, and _______ and _______ toward the center of a low
counterclockwise and outward; clockwise and inward
What four scales of motion are used in meteorology
microscale, macroscale, synoptic, global
planetary boundary layer
is described as the first 1000m above the surface
what is the difference between thermal turbulence and mechanical turbulence
thermal is caused by heating and cooling of the earth's surface, mechanical is caused by mountains and buildings
what are two types of eddies and what causes them
vertical - houses, mountains...
horizontal - islands, coastlines, mountain passes
thermal circulation
changes in wind and temperature because of adjacent surfaces having different properties (eg. land and sea, moist land and dry land)
What happens to wind when it reaches water?
It typically picks up speed because of the lack of friction. This will increase the effect of the Coriolis effect
Describe the mountain-valley breeze
blow uphill from the valley, while mountain breezes blow downhill from the mountain
Katabatic wind
The technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity
Chinook winds
are warm, dry winds that warm by compressional heating as they descend the leeward side of mountains
what does sea breeze do
blows from the surface water onto the land in response to local pressure differences created by the uneven heating and cooling rates of land and water.
Santa Ana Winds
is a warm, dry wind that warms by compressional heating as it descends the high plateau into Southern California
dust devils
(whirlwinds) are rotating winds that usually form in clear, hot weather in dry areas. They are not tornadoes
The two major semipermanent subtropical highs that influence the weather of North America are what
Pacific high and Bermuda high
where is the Pacific high situated
off the west coast
where is the Bermuda high situated
off the southeast coast
The subtropical high pressure areas with their sinking air and clear skies are primarily responsible for the major deserts of the world located near what latittude
30 degree latitude
The polar front is a zone of ____ pressure where storms often form. it separates the mild ____ from the cold, polar _____
low; westerlies, easterlies
The trade winds are located _________of the subtropical highs in both hemispheres
equatorward
Near the equator, the __________ is a boundary where air rises in response to the flowing together of the northeast trades and the southeast trades
intertropical convergence zone (ITCZ)
In the Northern Hemisphere, the major global pressure systems and wind belts shift _______ in summer and ___________ in winter
northward; southward
Warm air aloft (high pressure) over the tropics and subtropics, and cold air aloft (low pressure) over the middle and high latitudes produce ________ winds aloft in both hemispheres, especially in the middle and high latitudes.
westerly
_______ exist where strong winds become concentrated in narrow bands. They often form where sharp temperature changes produce rapid changes in ___________, such as aloft in the vicinity of the polar front.
Jet streams; pressure
Jet streams meander in a wavy west-to-east pattern, becoming strongest in _______ when the contrast in temperature between high and low latitudes is greatest
winter
Surface winds blowing over the ocean drive the major ocean currents. The currents, in turn, release _______ _____ ______ ___________ which helps the atmosphere maintain its general circulation of winds.
energy to the atmosphere
Upwelling occurs along ___ ___ where the prevailing winds blow parallel to the coast and the Coriolis force is able to bend the moving water seaward. Upwelling is especially prevalent along the ______coast of North and South America
coastal areas; west
A major El Niño event is a condition where _____surface water covers vast areas of the tropical Pacific. When the water in the equatorial Pacific turns _________ than normal, this condition is called La Niña.
warm; colder
An air mass is a large body of air with similar horizontal _________ and _________ characteristics.
temperature and moisture
Regions where air masses originate and acquire their properties of temperature and moisture are called __________. These are generally flat, of uniform composition, where winds are light.
source regions
Continental air mass forms over ____ and what is its symbol
land; lowercase 'c'
Maritime air mass forms over ____ and what is its symbol
water; lowercase 'm'
Polar air mass forms in ____ and what is its symbol
cold, polar latitudes; capital 'P'
Tropical air mass forms in ____ and what is its symbol
warm, tropical latitudes; capital 'T'
what is Arctic air and what is its symbol
extremely cold air masses; capital 'A'
__ air masses are cold and dry
cP; continental polar air
__ are masses are extremely cold and dry
cA; continental arctic air
__ air masses are hot and dry
cT; continental tropic
__ air masses are warm and moist
mT; maritime tropic
__ air masses are cold and moist
mP; maritime polar
A ________ is a transition zone that separates two air masses with contrasting properties, usually temperature and humidity.
front
A cold front is a region where ________ air is replacing ________ air. Typically, along the leading edge of the cold front, warmer air is forced upward producing a rather narrow band of showers.
colder, warmer
The cold front represents a trough of _______ pressure where there is a wind shift (often from SW to NW). After the passage of a cold front, air temperatures ______ and air pressures, often having fallen, begin to _______.
lower; drop, rise
A warm front is a region where warmer air is replacing colder air. Along the warm front, surface air, producing clouds and precipitation out ahead of the advancing surface front.
warmer air rides up and over colder
As a warm front approaches, the clouds often change from ______ clouds (Ci and Cs), to ______ clouds (As), to _____ clouds (Ns and St)
high, middle, low
An occluded front often has characteristics _______________________________. The coldest air is observed behind a _____ occlusion and ahead of a ______ occlusion.
of both a cold front and a warm front; cold, warm
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