Terms in this set (97)
the state of the earths atmosphere at a certain time and place.
can change from day to day.
year round weather typical of a certain place.
remains the same.
study of weather and its atmospheric conditions that it produces.
scientists who study weather.
3 major factors that work together to cause earth's variable weather
1.thermal(heat) energy. 2.uneven heat distribution of this energy. 3.water vapor in the atmosphere.
comes from the sun
2.indirectly:absorbing heat from sun - warmed land and water.
4% in troposphere.
water or ice falling to the earth(such as rain or snow)
process by which a molecule of a liquid becomes a gas.
how water enters our atmosphere.
more rapid when air is dry or when a breeze is blowing across the water.
the rate of evaporation is directly related to...
a molecule in the gaseous state...
...has more energy than a molecule in the liquid state.
heat of vaporization
extra energy gained by evaporating molecules.
unit of heat.
unit of mass.
..has a cooling effect.
liquid state of water.(when a gas returns to its liquid state)
heat of condensation
the amount of heat released when a gas changes to a liquid.
the temperature at which water vapor in the air begins to condense.(depends on pressure and humidity of the air)
will not condense into liquid water without a surface to condense upon.
if air near the ground cools below the dew point, water vapor will condense on the grass and soil, forming these droplets of water(clear cool nights produce heavier dew than cloudy nights - greenhouse effect)
liquid --> ice.
light, feathery deposits of ice crystals that results from sublimation.
the temperature at which frost begins to form.
microscopic particles of dust, soot and smoke, sea salt, sulfur trioxide, and ionized atoms floating in the atmosphere.
if temperatures fall below freezing , condensation nuclei become ____________.
temperatures fall below the dew point, water vapor in the air condenses into tiny droplets of water and forms a __________.
...result from adiabatic cooling of moist air.
4 ways of classifying clouds by shape and height
1.cumulus 2.cirrus 3.stratus 4.lenticular.
describes clouds found at higher altitudes.
cloud that produces precipitation
white, billowy clouds that resemble piles of cotton puffs in the sky.
-"heap" or "pile"
strong updrafts from huge, towering cumulus clouds.
...are also named by their ability to bring some form of precipitation.
smaller cumulus clouds at higher altitudes.
these clouds often form a flat, gray layer of heavy clouds not far above ground.
stratus rain clouds, the darker they are, the sooner you can expect rain(or snow).
"wisp or curl"
thin delicate clouds near the top of the troposphere.
"mares' tails" have feathery appearance.
consists of ice crystals rather than water droplets.
"shaped like a lens"
generally form over mountains.
several may be piled on top of one another like a stack of pankakes.
form a low, heavy layer of puffy, gray clouds.
some clouds do not fit...
...into just one family but share characteristics of more than one family.
to predict what the weather will be like several days into the future.
five most important properties of air
1.pressure 2.humidity 3.wind speed 4.wind direction 5.temperature
measures air temperature.
uses the expansion and contraction of a liquid in a a thin tube to inidicate the temperature.
most _________ use alcohol/mercury.
record highest/lowest temperatures of the day and night during a particular period.
special type of thermometer that records temperature changes over a period of time.
measures atmospheric pressure.
earliest and most common type of barometer.
more compact and rugged type of barometer.
uses a flexible, air tight metal box to measure changes in pressure.
1 millimeter of mercury
unit of pressure.
records changes in air pressure over a period of time.
amount of moisture in the air to the max amount it COULD hold.
measures relative humidity.
common type of hygrometer.
2 thermometers mounted side by side on a sling.
indicates direction of wind.
a simple device that points into the wind.
winds are named...
...for the direction from which they come.
measures wind speeds near the earths surface.
consists of rotating arms with cups at the ends to catch the wind.
most common and widely used.
thin, translucent clouds spread like a sheet in the upper troposphere.
look like tiny puffs of cotton in the upper troposphere.
when water vapor condenses in the layer of air near the ground.
a stratus cloud formed at the surface of the earth.
4 types of fog formation
1.radiation 2.advection 3.upslope 4.precipitation
usually occurs on clear nights, when greenhouse effect is reduced.
thick layer near the ground may be cooled below dew point causing cloud droplets to form around condensation nuclei in the air.
forms when a warm, humid breeze blows over a cold surface.
when advection fog forms over cold ocean water.
may be formed by moist winds blowing up a gentle slope.
warm rain falling into cool air.
combination of smoke and fog.
usually refers to a different form of air pollution.
a thick, brownish haze that results from complex molecules released into the air by cars(primarily older models), buses and trucks, lawnmowers, some factories, and certain trees and other plants.
these molecules are broken down by sunlight into other noxious chemicals forming the brownish haze
a large body of air with relatively uniform temperature, humidity, and pressure.
tend to move as a unit, going over, under, or around other air masses instead of mixing with them.
factors of air mass(es)
temperature, humidity, and pressure.
form when a body of air remains still long enough to acquire the characteristics of the region it inhabits.
tropical air mass
an air mass that forms in the tropics; will be quite warm; brings warm weather.
polar air mass
an air mass that forms over a polar region; will be cold; brings cooler weather.
maritime air mass
form over the sea, are generally very humid.
classes of air masses
maritime tropical, maritime polar, continental tropical, continental polar, arctic.
continental air mass
form over land, are almost always dry.
brings clear weather.
air masses that form over the the oceans of the tropics.
brings warm, humid weather accompanied by thunderstorms.
air masses that form over a desert or a tropical land area.
brings hot, dry weather.
air masses that form over the oceans of arctic regions.
brings cool, wet weather as they move south.
air masses that originate over cold land areas.
brings cold, dry weather.
air masses that form over snow and ice-covered portions of the arctic.
brings bitterly cold, dry weather as they move south.
air mass weather
when an air mass is passing over a region, the region experiences ___________.
the same general...
...weather conditions will prevail from one day to the next.
4 types of fronts
cold, warm , occluded, stationary.
when/where air masses meet.
named according to the air mass thats coming into the "territory" of another air mass.
if a mass of cold air moves into territory covered by a mass of warmer air.
produce thick clouds and severe weather.
...is denser(heavier) than cold air.(warm air rises, cold air sinks)
when a warm air mass moves into territory occupied by colder air, the lighter warm air flows up and over the heavy cold air like a wave breaking on the beach. because the warm air is advancing, its called _________.
type of front that occurs when 2 air masses meet and become stationary, neither displacing the other.
weather is similar to the bad weather that accompanies a warm front, usually lasts several days.
a whirlpool of low pressure that may form along a stationary front.
cold fronts move..
...faster than warm fronts.
when a fast moving cold front overtakes the slower moving warm front it forms a Y shaped front.
weather is a combination of that produced by warm and cold fronts.
23.5 degrees tilt of the earth's axis...
...the hemisphere that's tilted toward the sun recives more insolation.
equator gets more heat
the suns rays are more inclined at the poles than at the equator because of the earths spherical shape...
half of the earth....
....is always in the shadow.
land heats faster...
...and cools quicker than water.