1. Meteorology Basics Lecture Science 2201 (chapter 18)
“Climate is what you expect,
weather is what you get.”

2. Distinguish between…
Weather
Seasons
Climate

3. Chemical Composition of the Atmosphere
Nitrogen 78%
Oxygen 21%
Argon 0.9%
Carbon Dioxide 0.03%
Trace substances
Water Vapor

5. Vertical Structure of Atmosphere

7. 5 variables influence the atmosphere:
Temperature
Pressure
Humidity
Cloudiness
Winds

8. Variables influencing the atmosphere… temperature:
Measure of heat
Average kinetic energy of molecules
Weather reports give air temperature at ground level

9. Variables influencing the atmosphere… pressure:
High Pressure
Region where air has piled up
Warmer and dryer than surrounding air
Low Pressure
Region where air has stretched out
Tends to rise and cool, vapor condenses into clouds

10. Variables influencing the atmosphere… humidity:
“relative humidity” –
the ratio of
amount of water vapor in air at current temp to
max amount vapor air can hold at that temp

11. Variables influencing the atmosphere… cloudiness:
Water droplets
Ice crystals
Warm air rises, cools and condenses
(phase change)

12. Variables influencing the atmosphere… winds:
Due to differential heating of the earth’s surface
Warm air rises
Cooler air flows in

13. Check your neighbor. Make a sketch to explain your answer.
Why is it warmer near the Earth’s equator and colder near the poles? What patterns of global air flow occur?
Check your neighbor. Make a sketch to explain your answer.

14. Global Air Circulation Patterns

15. Where does your weather forecast come from?
National Weather Service
World Weather Building in Camp Springs, Maryland
Media weather specialists

16. Weather Forecasting Wrong half the time?
Many features, all are changeable
Nowcast  Forecast
CNN Weather link

17. The Instruments Thermometer Hygrometer Barometer Weathervane
Anemometer

18. The Instrument Carriers
10,000 land-based & 7,000 ocean-based
Weather Balloons (1,000 released 2X/day)
Buoys (300 drift or are moored at sea)
Automated Weather Stations (about 1,000)
Doppler Radar
Satellites

19. Reading a Weather Map Pressure Centers Fronts Precipitation
Temp. Readings
Surface Winds

20. Winter Air Masses
Continental Polar
Maritime Polar
Maritime Tropical

21. Summer Air Masses Continental Polar Maritime Tropical
Continental Tropical

22. “Fronts” = a clash of air masses
Cold Front
digs in underneath a warm air mass
Warm air rises, mixes with colder air, & condenses into clouds

23. “Fronts” = a clash of air masses
Warm Front
rides up above the cold air
In the rising warm air, clouds form far ahead of advancing warm front

25. Air Masses Doing Battle link Cloud Classification link