Meteorology : The Science of Weather (Part 2)

1. Meteorology:The Science of Weather (Part 2) Follow along with this PowerPoint and take notes in your Meteorology Foldable

2. Foldable Topics • Winds • Gyres • Ocean Currents • Weather Tools & Equipment Jet Stream Air Masses

3. Jet Stream Jet Stream: “river” of air in the upper troposphere with very high wind speed The jet stream’s high winds are caused by the difference of temperatures between two air masses. Jet streams usually form in the winter Jet streams do not cause weather. They are the result of weather conditions such as temperature differences.

4. Air Masses Air Mass: a body of air over a large area that develops and keeps characteristics of pressure, temperature, and humidity of the area over which it develops

5. Air Mass Types • Types- Location • Maritime: develop over oceans, so they are moist • Continental: develop over land, so they are dry • Types- Temperature • Arctic: develop in the arctic region, so they are very cold • Polar: cold, but not as cold as arctic • Tropical: develops in tropical regions near the equator so they are very warm

6. Air Masses • Combine the location and temperature names to get a description of the air mass • Continental Arctic (cA): extremely cold and dry • Continental Polar (cP): cold and dry • Maritime Polar (mP): cold and moist • Maritime Tropical (mT): warm and moist • Continental Tropical (cT): hot and dry

7. Global Air Masses

8. Winds Wind: Movement of air caused by differences in density and pressure of air “High to Low makes the WIND BLOW!”

9. Winds & Coriolis Effect Earth’s rotation or “spin” causes winds to be deflected or “turned” to the right in the northern hemisphere and left in the southern hemisphere.

10. Wind & Convection Cells • Convection Cells: uneven heating of the Earth’s surface causes bands of wind that blow in a certain direction. • Winds are named for the direction they come from • Easterlies come from the east • Westerlies come from the west Doldrums: area near the Equator with little or no wind

11. Gyres- “swirling vortex” • Gyres: large areas of water that swirl due to the Earth’s rotation • Water swirls to the right in the Northern Hemisphere • Water swirls to the left in the Southern Hemisphere • Major Gyres: • North Pacific Ocean (clockwise) • South Pacific Ocean (counterclockwise) • Indian Ocean (counterclockwise) • South Atlantic Ocean (counterclockwise) • North Atlantic Ocean (clockwise)

12. Major Ocean Gyres

13. Ocean Currents • Ocean Current: movement of ocean water in a certain direction • Ocean currents result from heating from the sun (produces wind) and Earth’s rotation (Coriolis Effect) • Types: • Surface currents • Deep Ocean Currents

14. Surface Currents • Surface Currents: ocean currents at the surface or top of the ocean. Surface currents are caused primarily by wind and the Coriolis Effect • Gulf Stream: surface current that starts in southern Florida and flows along the eastern U.S. coast. • The Gulf Stream’s warm water influences climate in its path because it carries warm tropical water near the equator to colder areas in the north. • Hurricanes travel in its path.

15. Ocean Currents

16. Deep Currents • Deep Ocean Currents: ocean currents deeper in the ocean caused by density differences due to salinity (salt content). • These currents involve 90% of the ocean’s water • The water that sinks in the North Atlantic flows all the way past the equator into the Southern Hemisphere. • The water then flows past Antarctica and into the Pacific and Indian Oceans. Here some of the deep waters are warmed and so rise again to the surface. • This cycle of ocean water circulation from the surface to the deep ocean and back to the surface again is called conveyor belt cycling.

17. Conveyor Belt Cycling

18. Tools of the Trade

19. Barometer • A device used to measure atmospheric pressure. • Common pressure units include pounds per square inch (psi) • Atmospheric pressure at sea level is about 14.7 pounds per square inch

20. Anemometer • Instrument used to measure the speed of airflow in the atmosphere. • Revolving cups drive an electric generator which operates an electric meter that is calibrated in wind speed. • Common unit is km/h • Common unit over water is “knot”, or one nautical mile per hour. This equals 1.15 mph over land.

21. Hygrometer • Instrument used to measure the humidity, or amount of water vapor, in the air • Theymake use of the principle that organic substances contract and expand in response to the humidity

22. Psychrometer • A hygrometer used to determine the relative humidity of the air. • The bulb of one thermometer is kept wet (by a thin, wet cloth wick) so that the cooling that results from evaporation makes it register a lower temperature than the dry-bulb thermometer • Relative humidity is determined as a %

23. Weather Balloons • A balloon with a radiosonde attached to it which measures weather data. • The radiosonde measures weather data. A transmitter on the radiosonde sends the data back to tracking equipment on the ground every one to two seconds.  • The balloon flights last for around 2 hours, can drift as far as 125 miles away, and rise up to over 100,000 ft. (about 20 miles) in the atmosphere! • Weather balloons are the primary source of data above the ground.

25. Weather Maps • TWC - Interactive Weather Map • NOAA – Current Weather Forecast