| A | B |
|---|
| air pressure | the force exerted by the weight of a column of air above a given point |
| anticyclone | a high-pressure center characterized by a clockwise flow of air in the Northern Hemisphere |
| barometer | an instrument that measures atmospheric pressure |
| Coriolis effect | the apparent deflective force of Earth’s rotation on all free-moving objects, including the atmosphere and oceans; Deflection is to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. |
| cyclone | a low-pressure center characterized by a counterclockwise flow of air in the Northern Hemisphere |
| El Niño | the name given to the periodic warming of the ocean that occurs in the central and eastern Pacific; A major El Niño episode can cause extreme weather in many parts of the world. |
| jet stream | swift (120–240 kilometers per hour), high-altitude winds |
| monsoon | seasonal reversal of wind direction associated with large continents, especially Asia; In winter, the wind blows from land to sea. In summer, the wind blows from sea to land. |
| polar easterlies | in the global pattern of prevailing winds, winds that blow from the polar high toward the subpolar low; These winds, however, should not be thought of as persistent winds, such as the trade winds. |
| 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 occurring over a given distance |
| prevailing wind | a wind that consistently blows from one direction more than from another |
| trade winds | two belts of winds that blow almost constantly from easterly directions and are located on the north and south sides of the subtropical highs |
| westerlies | the dominant west-to-east motion of the atmosphere that characterizes the regions on the poleward side of the subtropical highs |
| anemometer | an instrument used to determine wind speed |
