| A | B |
|---|
| Altitude | the height of an object above a reference point, such as sea level or the Earth's surface |
| Air pressure | the measure of the force with which air molecules push on a surface |
| As altitude increases | air pressure decreases. |
| troposphere | the lowest layer of the atmosphere and is characterized by a constant drop of temperature with increasing altitude |
| stratosphere | the upper layer of the atmosphere, which lies immediately above the troposphere |
| mesosphere | (literally, the "middle sphere") is the coldest layer of the atmosphere |
| thermosphere | the uppermost layer of the atmosphere, in which temperature increases as altitude increases. The thermosphere includes the ionosphere |
| Radiation | energy that is transferred as electromagnetic waves, such as visible light and infrared waves |
| Conduction | the transfer of thermal energy as heat through materials |
| Convection | the movement of matter resulting from differences in density that are caused by temperature variations. Convection can result in the transfer of energy as heat. |
| greenhouse effect | the warming of the surface of the Earth and the lower atmosphere as a result of the buildup of carbon dioxide and water vapor, which absorb and reradiate infrared radiation. |
| Radiation balance | the balance between incoming energy and outgoing energy. |
| Global warming | a gradual increase in the average global temperatures that is due to a higher concentration of gases such as carbon dioxide in the atmosphere. |
| Wind | is created by differences in air pressure. The greater the pressure difference is, the faster the wind moves. |
| Surface winds | generally blow from polar, high-pressure areas to equatorial, low-pressure areas |
| Pressure belts | bands of high or low air pressure that circle the Earth at about every 30° of latitude |
| convection cell | a pattern of circulation in which warmer materials rise in one location, while cooler materials sink in another location |
| Coriolis effect | the curving of the path of a moving object from an otherwise straight path resulting from the Earth's rotation |
| Trade winds | prevailing winds that blow northeast from 30° north latitude to the equator and that blow southeast from 30° south latitude to the equator. |
| Westerlies | prevailing winds that blow from west to east between 30° and 60° latitude in both hemispheres. |
| Polar easterlies | prevailing winds that blow between 60° and 90° latitude in both hemispheres. |
| Local winds | winds that are influenced by the geography of an area. |
| Acid precipitation | precipitation, such as rain, sleet, or snow, that contains a high concentration of acids, often because of the pollution of the atmosphere |
| Ozone | a gas molecule that is made up of three oxygen atoms |
| ozone layer | the layer of the atmosphere at an altitude of 15 to 40 km in which ozone absorbs ultraviolet solar radiation. |
