1. Chapter 12 Meteorology

2. Meteorology = the study of meteors? Meteoros = anything high in the air Meteorologists study: – Hydrometeors: rain, snow, sleet, hail – Lithometeors: dust, smoke, haze, particles – Electrometeors: lightning, thunder Weather (short term) vs. climate (long term)

3. Imbalanced heating What makes summer warmer than winter? Number of hours of daylight and angle of the sun’s rays

4. Air masses Movement of air and water distribute heat around the earth Air masses take on the properties of their source regions. – Polar = cold – Tropical = warm – Maritime = humid – Continental = dry – Arctic: very cold/dry

5. Coriolis Effect Moving air curves clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere Creates global wind systems: – Polar easterlies – Westerlies – Trade winds – Horse latitudes – Equatorial low (ITCZ)

6. Jet Streams Narrow bands of fast westerly wind Position varies seasonally Polar and subtropical Storms form along jet stream paths

7. Weather Fronts Stationary front

8. Pressure Systems In a low pressure system, air rises, cools and forms clouds Air sinks in a high pressure system, usually associated with fair weather

9. Weather Observation Systems Automated surface observing system Radiosonde (upper atmosphere weather balloon) Weather radar (including doppler) Weather satellites (infrared, visible and water- vapor imagery)

10. Weather Data Temperature (thermometer) Air pressure (barometer) Wind speed (anemometer) Relative humidity (hygrometer)

11. Weather Station Models A station model is a record of weather data for a specific place at a specific time Uniform way of communicating weather data Lots of information in a small space

12. Map with weather stations

13. Same map with Isotherms

14. Same map with Isobars

15. Short and Long Term Forecasts Short-term More detailed and accurate Hourly forecast based on present weather One- to three-day forecasts based on larger systems such as low pressure systems Long-term Less reliable because of great number of variables involved Based on large scale circulation patterns and weather cycles