| A | B |
|---|
| Air Mass | A large body of air in the troposphere with similar characteristics of pressure, moisture, and temperature |
| Air pressure gradient | The amount of difference in air pressure over a specific distance |
| Anemometer | A weather instrument to measure wind speed |
| Atmospheric Pressure | The weight of the overlying atmospere pushing down on a given unit of area |
| Atmospheric Transparency | How transparent the atmosphere is to insolation |
| 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 |
| cold Front | The boundary of an advancing cold air mass and a warmer air mass where the underlying cold air pushes forward like a wedge |
| Cyclone | A low pressure portion of the troposphere that has air moving towards its center |
| Cyclonic Storm | A large type of low pressure storm system formed in the mid-latitudes |
| Dew Point | The temperature at which the air becomes saturated with water vapor and the relative humidity is 100% |
| Front | The interface, or boundary, 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 concentrated 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 |
| Occluded Front | The boundary of opposing wedges of cold air masses formed when a cold front overtakes a warm front |
| planetary wind Belt | East-West zones on earth where the wind blows from one direction much of the time |
| polar front | An ever-changing boundary between the colder air masses toward the poles and the warmer air masses toward the middle latitudes |
| precipitation | Falling liquid or solid water from clouds toward Earth's surface |
| probability | The chance of some environmental event, such as rain or an earthquake, taking place |
| psychrometer | An instrument that is used to indirectly measure the amount of water vapor in air |
| radar | An instrument that uses radio/microwave electromagnetic radiation to observe many weather features such as precipation, tornadoes, and huirricanes |
| relative humidity | The ratio of the amount of water vapor in the air to the maximum amount it can hold |
| stationary front | A weather condition in which the boundary between two air masses remains in the same position |
| station model | Cities and other weather station sites on weather maps represented by circles, with symbols in and around each circle that indicate the many weather variables |
| troposphere | The part of the atmosphere immediately above earth's surface |
| Visibility | The farthest distance at which one can see a prominent object at earth's surface with the naked eye |
| Warm Front | The boundary of an advancing warm air mass and a retreating wedge of a cooler air mass |
| Water Vapor | Gaseous water in the atmosphere |
| Weather Variables | Condition of the atmosphere such as temperature, air pressure, wind, moisture conditions, cloud cover, precipitation and storms |
