cirrus
thin, delicate, ice-crystal clouds often appearing as veil-like patches or thin, wispy fibers
condensation
the change of state of matter from a gas to a liquid
condensation nuclei
tiny bits of particulate matter that serve as surfaces on which water vapor condenses
cumulus
billowy individual cloud masses that often have flat bases
deposition
the process by which water vapor is changed directly to a solid without passing through the liquid state
dew point
the temperature to which an air mass has to be cooled in order to reach saturation
evaporation
the process of converting a liquid to a gas
front
the boundary between two adjoining air masses having contrasting characteristics
humidity
a general term referring to water vapor in the air
hygrometer
an instrument designed to measure relative humidity
latent heat
the energy absorbed or released during a change of state
precipitation
any form of water that falls from a cloud
relative humidity
the ratio of the air's water vapor content to its water vapor capacity
saturated
the state of air that contains the maximum quantity of water vapor that it can hold
stratus
clouds in sheets or layers that cover much or all of the sky
sublimation
the conversion of a solid directly to a gas without passing through the liquid state
Supercooled water
the condition of water droplets that remain in the liquid state at temperatures well below freezing
supersaturated air
the condition of air that is more highly concentrated than is normally possible; refers to a relative humidity that is greater than 100 percent
temperature inversion
condition in which temperature increases with altitude, rather than decreasing, causing the air to turn over
albedo
the fraction of total radiation that is reflected back by a surface
autumnal equinox
the equinox that occurs in September in the Northern Hemisphere and in march in the Southern Hemisphere
conduction
the transfer of heat through matter by molecular activity; energy is transferred through collisions from one molecule to another
convection
the transfer of heat by the movement of a mass or substance; can take place only in fluids
heat
thermal energy transferred from one object to another
isotherm
a line connecting points of equal temperature
mesosphere
the layer of the atmosphere immediately above the stratosphere and characterized by decreasing temperatures with height
ozone
a molecule of oxygen containing three oxygen atoms
radiation
the transfer of energy through space by electromagnetic waves
reflection
the process whereby light bounches back from an object
scattering
the redirecting of light by small particles and gas molecules in the atmosphere
spring equinox
the equinox that occurs in March in the Northern Hemisphere
stratosphere
the layer of the atmosphere above the troposphere, characterized by increasing temperatures with height, due to the concentration of ozone
summer solstice
the solstice that occurs in June in the Northern Hemisphere and December in the Southern Hemisphere
temperature
a measure of the average kinetic energy of individual atoms or molecules in a substance
thermosphere
the region of the atmosphere immediately above the mesosphere and characterized by increased temperatures with height due to the absorption of very short-wave energy by oxygen
troposphere
the lowermost layer of the atmosphere characterized by a decrease in temperatures with height
winter solstice
the solstic that occurs in December in the Northern Hemisphere and June in the Southern Hemisphere
air mass
a large body of air that is characterized by similar temperatures and amounts of moisture
cold front
a front along with a cold air mass moves benath a warmer air mass
eye wall
the doughnut-shaped area with very strong winds that surrounds the eye of a hurricane
eye
a zone of scattered clouds and calm at the center of a hurricane
front
the boundary between two adjoining air masses having contrasting characteristics
hurricane
a tropical cyclonic storm having winds over 119 km/hr
occluded front
a front formed when a cold front overtakes a warm front
stationary front
a situation in which the surface position of a front does not move
storm surge
the abnormal rise of the sea along a shore as a result of strong winds
thunderstorm
a storm produced by a cumulonimbus cloud and always accompanied by thunder and lightning
tornado
a small, very intense cyclonic storm with exceedingly high winds, most often produced along cold fronts in conjunction with severed thunderstorms
warm front
a front along which a warm air mass moves up and over a retreating mass of cooler air
air pressure
the force exerted by the weight of air
anemometer
an instrument used to determine wind speed
anticyclone
a high-pressure center; winds blow clockwise in the northern hemisphere
barometer
an instrument that measures atmospheric pressure
coriolis effect
the apparent deflective force of Earth's rotation on free-moving objects, including the atmosphere and oceans. Deflects to the right in the northern hemisphere and to the left in the southern hemisphere
cyclone
a low-pressure center; winds blow counterclockwise in the northern hemisphere
El Nino
periodic warming of the ocean in the central and northern Pacific; can cause extreme weather
jet stream
swift, high-altitude winds
monsoon
seasonal reversal of wind direction associated with large continents, such as Asia
polar front
the stormy frontal zone separating cold air masses of polar origin from warm air masses of tropical origin
pressure gradient
the amount of pressure change occuring over a given distance
prevailing wind
a wind that consistenly blows from one direction more than from another
trade winds
two belts of winds that blow almost constantly from easterly directions
global warming
the increase in average temperatures of Earth and the atmosphere
greenhouse effect
the heating of Earth's surface and atmosphere by solar radiation being absorbed and emitted by the atmosphere