Meteorology Flashcards
air mass
a huge body of air that has similar temperature, humidity, and air pressure at any given height
continental polar (cP)
cold, dry air mass that forms over land
continental tropical (cT)
warm, dry air mass that forms over land
maritime polar (mP)
cold, moist air mass that forms over cold oceans
maritime tropical (mT)
warm, moist air mass that is formed over water
continental arctic (cA)
very cold, very dry air mass
front
the atmospheric phenomenon created at the boundary between two different air masses
cold front
forms when cold air moves under warm air which is less dense and pushes air up (produces thunderstorms heavy rain or snow
warm front
a front where warm air moves over cold air and brings drizzly rain and then are followed by warm and clear weather
occluded front
a front where a warm air mass is caught between two colder air masses and brings cool temperatures and large amounts of rain and snow
stationary front
weak cold and warm air masses meet, but neither can move the other
thunderstorm
the most common severe storm, formed in cumulonimbus clouds
hurricane
a severe storm that develops over tropical oceans and whose strong winds of more than 120 km/h spiral in toward the intensely low-pressure storm center
tornado
a localized and violently destructive windstorm occurring over land characterized by a funnel-shaped cloud extending toward the ground
weather station model
a group of symbols used to communicate weather at a given place on Earth’s surface; Data includes temperature current precipitation, pressure and pressure change, dew point, etc
Coriolis effect
The way Earth’s rotation makes winds in the Northern Hemisphere curve to the right and winds in the Southern Hemisphere curve to the left
trade winds
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
horse latitudes
are regions of high pressue and gentle winds at about 30 degrees north and south latitude
doldrums
a belt of calms and light winds between the northern and southern trade winds of the Atlantic and Pacific
westerlies
prevaling winds that blow from west to east between 30 degrees & 60degrees latitude in the hemisphere
polar easterlies
prevailing winds that blow from east to west between 60 degrees and 90 degrees latitude in both hemispheres
sub-polar low
a low pressure area formed sixty degrees N when the prevailing westerlies rise above the polar easterlies
jet stream
a high-speed high-altitude airstream blowing from west to east near the top of the troposphere
isobar
a line drawn to connect points of equal atmospheric pressure
air pressure
the measure of the force with which air molecules push on a surface
pressure gradient
the amount of pressure change occurring over a given distance
high pressure
cool dense sinking air; associated with clear skies and calm weather
low pressure
warm rising area that condenses and cools; associated with cloudy skies, precipitation, and wind
water vapor
water in the form of a gas
condensation
the process of changing from a gaseous to a liquid or solid state
specific humidity
the amount of water vapor in the air at a given time and place; expressed as the number of grams of water vapor per kilogram of air.
saturated
being the most concentrated solution possible at a given temperature
capacity
the amount that can be contained
relative humidity
the ratio of the amount of water in the air at a give temperature to the maximum amount it could hold at that temperature
dew point
temperature at which air is saturated and condensation begins
condensation nuclei
microscopic particles (such as dust or ice) on which water vapor condenses to form cloud droplets
precipitation
the falling to earth of any form of water (rain or snow or hail or sleet or mist)
sleet
partially melted snow (or a mixture of rain and snow)
hail
lumps or balls of ice that fall from cumulonimbus clouds formed from strong convection currents adding layers of ice
glaze
a coating of ice on objects formed when supercooled rain freezes on contact
freezing rain
raindrops that freeze after they hit the ground or other cold surfaces
evaporation
the process by which water changes from liquid form to an atmospheric gas
cloud
a visible mass of water or ice particles suspended at a considerable altitude
scattering
the physical process in which particles are deflected haphazardly as a result of collisions
reflection
the phenomenon of a propagating wave (light or sound) being thrown back from a surface
absorption
(chemistry) a process in which one substance permeates another
conduction
the transfer of thermal energy from one substance to another through direct contact
convection
the transfer of heat through a fluid (liquid or gas) caused by molecular motion
ozone layer
a layer in the stratosphere (at approximately 20 miles) that contains a concentration of ozone sufficient to block most ultraviolet radiation from the sun
greenhouse effect
natural situation in which heat is retained in Earth’s atmosphere by carbon dioxide, methane, water vapor, and other gases
global warming
an increase in the average temperature of the earth’s atmosphere
isotherm
line on a map connecting points equal temperature values
insolation
the amount of the sun’s energy that reaches earth at a given time and place
albedo
the fraction of solar radiation that is reflected off the surface of an object
radiation
energy that is radiated or transmitted in the form of rays or waves or particles
isobar
a line drawn to connect points of equal atmospheric pressure
troposphere
the layer of the atmosphere that contains life and weather; the temperature decreases as you go up
tropopause
is the boundary between the troposphere and the stratosphere
stratosphere
the layer of the atmosphere that is above the troposphere and in which temperature increases as altitude increases
stratopause
the transition between the stratosphere and the mesosphere
mesosphere
the layer of the atmosphere immediately above the stratosphere and characterized by decreasing tempertures with height and where most meteors burn up
mesopause
the transition between the mesosphere and the thermosphere
thermosphere
The uppermost layer of the atmosphere, in which temperature increases as altitude increases
ionosphere
layer of electrically charged particles in the thermosphere that absorbs AM radio waves during the day and reflects them back at night
exosphere
the layer of the atmosphere that fades into outer space
weather
the condition of Earth’s atmosphere at a particular time and place
vorticity
tendency of an air parcel to spin
earth vorticity
vorticity due to Earth’s daily rotation about its axis, is a function solely of latitude higher the latitude, the greater the vorticity
relative vorticity
the vorticity relative to Earth’s surface
absolute vorticity
relative vorticity + Earth’s Vorticity
unstable cloud
Cumulus
stable cloud
Stratis
jet streak
a region of high wind speed that moves through the axis of a jet stream
