| A | B |
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| weather | short-term variations in atmosphere phenomena that interact and affect the environment and life on Earth |
| climate | the long-term average of variation in weather for a particular area |
| air mass | large volume of air that has the characteristics of the area over which it forms |
| source region | area over which an air mass forms |
| Coriolis effect | effect of a rotating body that influences the motion of any object or fluid; on Earth, air moving north or south from the equator appears to move right or left, respectively; the combination of the Coriolis effect and Earth's heat imbalance creates the trade winds, polar easterlies, and prevailing westerlies |
| polar easterlies | global wind systems that lie between latitudes 60 degrees N and 60 degrees S and the poles and is characterized by cold air |
| prevailing westerlies | global wind system that lies between 30 and 60 degrees N & S latitudes, where surface air moves toward the poles in an easterly direction |
| trade winds | two global wind systems that flow between 30 degrees N & S latitudes, where air sinks, warms, and returns to the equator in a westerly direction |
| jet stream | narrow wind band that occurs above large temperature contrasts and can flow as fast as 185 km/h |
| front | boundary between two air masses of differing densities; can be cold, warm, stationary, or occluded and can stretch over large areas of Earth's surface |
| thermometer | instrument used to measure temperatue using either the Fahrenheit or Celsius scale |
| barometer | instrument used to measure air pressure |
| anemometer | weather instrument used to measure wind speed |
| hygrometer | weather instrument used to measure humidity |
| radiosonde | balloon-borne weather instrument whose sensors measure air pressure, humidity, temperature, wind speed, and wind direction of the upper atmosphere |
| Doppler effect | change in the wave frequency that occurs due to the relative motion of the wave as it moves toward or away from an observer |
| station model | record of weather data for a specific place at a specific time, using meteorological symbols |
| isobar | line on a weather map connecting areas of equal pressure |
| isotherm | line on a weather map connecting areas of equal temperature |
| digital forecast | weather forcast that uses numerical data o predict how atmospheric variables change over time |
| analog forecast | weather forecast that compares current weather patterns to patterns that occurred in the past |
