| A | B |
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| air mass | a large body of air in the troposphere with similar characteristics of pressure, moisture, and temperature |
| air pressure gradient | the amounf of difference in air pressure over a specific distance; the greater the gradient, the greater the speed of the wind |
| anemometer | a weather instrument used to measure wind speed |
| barometric atmospheric | the weight of the overlying atmosphere pushing down on a given unit of area; affected by changes in temperature, water vapor, and altitude |
| atmospheric pressure | the weight of the overlying atmosphere pushing down on a given unit of area; affected by changes in temperature, water vapor, and altitude |
| atmospheric transparency | how transparent the atmosphere is to isolation; how easily isolation can pass through the air |
| barometer | an instrument used to measure air pressure |
| cloud cover | the fraction or percent of the total sky at a location that is covered by clouds; usually expressed in tenths |
| cold front | the boundry of advancing cold air mass and a warmer mass, where the underlying cold air pushes forward like a wedge; characterized by a steep slope, rapid changes in weather,thunderstorms, and sometimes hail and tornadoes |
| cyclone | a low pressure portion of the troposphere that has air moving towards its center, usually rotated counterclockwise in the Northern Hemisphere and |
| cyclonic storm | a large type of low-pressure storm system formed in the mid-latitudes; also called mid-latitude cyclones |
| dew point | the temperature at which air become saturated aith water vapor and the relative humidity is 100% |
| front | the interface, or boundry, between two air masses of different characteristics |
| humidity | the amount of water vapor in the atmosphere |
| isobar | an isoline used on weather and climate maps that connects points of equal air pressure |
| jet stream | a concetrated curving band of high speed, easterly moving winds usually at the top of earth's troposphere |
| monsoon | cyclic and extreme weather changes caused by the shifting wind and pressure belts; especially strong in southeast Asia where summer brings wet weather from the ocean and winter brings dry weather from the mountains |
| occluded front | the boundry of opposing wedges of cold air masses formed when a cold front overtakes a warm front, lifting the warm air mass off Earth's surface, forming mid-latitude clouds |
| planetary wind belt | east-west zones on Earth where the wind blows from one direction much of the time |
| polar front | an ever-changing boundry between the cold air masses toward the poles and the warmer air masses toward the mid-latitudes |
