| A | B |
|---|
| air pollutants | any harmful matter added to the air |
| troposphere | the layer of the atmosphere closesst to the earth's surface |
| stratosphere | the layer of the atmosphere above the troposphere |
| ozone | a three-atom form of oxygen, which is in the stratosphere and absorbs harmful ultraviolet light, thereby protecting life on earth |
| mesosphere | the layer of the atmosphere above the stratosphere |
| thermosphere | the atmosphere's top layer |
| ionosphere | the region within the atmosphere containing ionized molecules (molecules that have lost or gained one or more electrons due to absorbing ultraviolet energy |
| wind vane | measures wind direction |
| anemometer | measures wind speed |
| air pressure | a force on a given area due to the weight of air |
| barometer | an instrument used to measure air pressure |
| humidity | the amound of water vapor in the air |
| hygrometer | measures humidity |
| relative humidity | the amount of water vapor in the air compared to the greatest amount the air can hold |
| dew-point temperature | the temperature at which the relative humidity is 100% |
| precipitation | falling particles of water or ice, such as rain or snow |
| radiosonde | a package of instruments attached to a radio transmitter that measures weather conditions carried high above the ground by a balloon |
| radar | used by meteorologiststo find rain or snow within clouds, track storms, etc. |
| satellites | give a complete picture of cloud patterns over huge areas |
| knot | a unit of measure used for wind speed |
| isobars | lines on a weather map connecting places with equal pressure |
| isotherms | lines on a weather map connecting places of equal temperature |
| air mass | a large region of air with similar properties throughout |
| high pressure area | brings clear skies, fair weather with little wind |
| low pressure area | causes clouds and precipitation |
| fronts | a boundary between two different air masses, where weather is usually unsettled and stormy |
| warm front | moves so that warm air replaces a colder air mass |
| cold front | where cold air replaces a warmer air mass |
| occluded front | when a cold front overtakes a warm front |
| stationary front | a front that is not moving |
| calorie | the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius |
| insolation | INcoming SOLar radiATION |
| absorbed sunlight | energy from the sun that is absorbed by the atmosphere |
| reflected sunlight | sunlight that is reflected by the clouds, either upward into space,or down toward earth's surface |
| diffuse sunlight | sunlight reflected within the atmosphere |
| heat capacity | the capacity of different materials to absorb energy, measured in the number of calories needed to warm the substance by 1 degree C |
| conduction | the movement of heat energy from molecule to molecule |
| convection | the movement of heat by warm and cold currents |
| latent heat | the energy stored in molecules through evaporation |
| radiation | the release and transfer of energy in wavelengths of heat and light |
| iinfrared radiation | energy radiating from the earth's surface |
| greenhouse effect | the ability of the atmosphere to let much sunlight in, but little infrared radiation to escape, which keeps earth warmer than it would otherwise be |
| energy budget | a sum of all energy gains and losses |
| saturated | completely filled - when the air is saturated it contains the greatest possible amount of water |
| dew | water that condenses onto cool surfaces |
| frost | water vapor that freezes as it condenses |
| condensation nucleus | any particle onto which water vapor condenses |
| cumulus cloud | puffy, heaped cloud |
| cumulonimbus cloud | a cumulus cloud that produces precipitation |
| stratus cloud | flat, sheet-like cloud |
| inversion | a layer of warm air lying above a layer of cold air |
| fog | a stratus cloud touching the earth |
| freezing nucleus | a particle in the air around which water droplets collect and freeze |
| supercooled | describes liquid water at temperatures below 0 degrees C |
| cirrus cloud | a feathery cloud made of ice crystals |
| halo | a circle of hazy white light around the sun or moon, caused by a cirrus cloud |
| three-phase process | a process wihic occurs in supercooled clouds and causes most precipitation |
| collision process | the process whereby water droplets in clouds stick together |
| drizzle | rain composed of very small drops |
| sleet | rain that has frozen before reaching the ground |
| hail | precipitaiton in the form of pellets made of layers of ice and snow |
