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Air Mass, Wind, and Weather Systems Sixth Grade GPS Earth Science Pam Myers.

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Presentation on theme: "Air Mass, Wind, and Weather Systems Sixth Grade GPS Earth Science Pam Myers."— Presentation transcript:

1 Air Mass, Wind, and Weather Systems Sixth Grade GPS Earth Science Pam Myers

2 Quick Review What causes wind? Answer: UNEVEN HEATING OF THE EARTH BY THE SUN.

3 Air Masses A large body of air that has nearly the same temperature, humidity & air pressure throughout They have similar properties as the part of the earth’s surface over which they form

4 Why are Air Masses important? They can cover an area of thousands of square kilometers. are responsible for day to day weather changes. Move/change – so does weather in area over area over which it moves.

5 x Less Dense Rises Up holds more moisture More Dense Sinks Down holds less moisture

6 Which Way Do The Winds Blow? From ___________ pressure to _____ pressure. high low Do you know what instrument we use to measure air pressure? A Barometer

7 Quick Review Is hot air high pressure or low pressure? Answer: LOW PRESSURE means it rises, and it holds more moisture than cold air

8 WEATHER SYSTEMS

9 Front? What is a Front? boundary between two air masses of –different density –moisture –temperature Four types of fronts; can you name them?? _____________, ______________ _____________, and __________________ _____________, and __________________ Warm front Cold front Occluded frontStationary front

10 Precipitation Along a Cold Front lifting the warm moist air ahead of it

11 Precipitation Along a Warm Front warm moist air overriding colder air

12 Quick Review Is cold air high pressure or low pressure? Answer: HIGH PRESSURE means it sinks, and it holds less moisture than cold air

13

14 Cool, dry Air mass … …butts against an equally strong mass of warm, humid air. Stationary front Warm Air Cool Air Battle for control ends with no winners; front moves little.

15 #1 Cold Front #2 Warm Front #4 Occluded Front #3 Stationary Front

16 Quick Review Which type of air rises? Which one sinks? Answer: HOT AIR ( LOW PRESSURE ) rises, and cold air (high pressure) sinks.

17 What information do you need to know to forecast weather??  Temperature  Winds  Air pressure  Humidity  Precipitation

18 Rain F ROZEN PRECIPITATION MELTS AND REACHES THE GROUND AS RAIN. Freezing Rain F ROZEN PRECIPITATION MELTS IN WARM AIR. R AIN FALLS AND FREEZES ON COLD SURFACE Sleet F ROZEN PRECIPITATION MELTS IN SHALLOW WARM AIR. T HEN REFREEZES BEFORE REACHING THE GROUND. Snow P RECIPITATION FALLS THROUGH COLD AIR AND REACHES THE SURFACE.

19 So What is a Hailstone?  begins as frozen raindrop or ice crystal –Travels through different levels of storm cloud –Strong warm air updrafts & cool air downdrafts –move frozen particles up & down

20 So What is a Hailstone?  encounters different forms of moisture  layers of frozen ice particles accumulate on surface  The resulting hailstone has a layered structure /earth_science/terc/content/visu alizations/es1805/es1805page0 1.cfm?chapter_no=visualization /earth_science/terc/content/visu alizations/es1805/es1805page0 1.cfm?chapter_no=visualization

21 Quick Review What about cold air? Is it high pressure or low pressure? Answer: HIGH PRESSURE means HIGH density, HIGH pressure, it sinks, and it does not hold much moisture

22 Do you know the scientific name for a weather forecaster?

23 A Meteorologist  measure temperature, air pressure, winds, humidity, and precipitation.  Tools Doppler radar, satellites, instruments attached to balloons  gather information from Earth’s upper atmosphere and the surface

24 A weather map shows surface- pressure systems, air masses, fronts (G REEN - SHADED AREA REPRESENTS PRECIPITATION ) isobars (millibars): SOLID GRAY LINES. L ARGE ARROWS IN COLOR SHOW AIR FLOW. (G REEN - SHADED AREA REPRESENTS PRECIPITATION.) Isotherms : SIMILAR TO ISOBARS, EXCEPT THEY SHOW TEMPERATURE (N OT S HOWN HERE )

25 References  Glencoe Science  


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