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Atmosphere 2 Notes
1. The document discusses various weather phenomena including air pressure, wind, air masses, fronts, and storms. It provides definitions and explanations of these concepts. 2. Key terms that are defined include high and low pressure systems, isobars, warm and cold fronts, thunderstorms, tornadoes, and hurricanes. Measurement tools like barometers and anemometers are also explained. 3. Visuals like diagrams and videos are referenced throughout to enhance understanding of complex weather patterns and interactions between different elements.
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Atmosphere 2 Notes
- 1. 1 ATMOSPHERE 2: Weather ppt. byRobin D. Seamon
- 2. 2 Measuring Weather: air pressure mercurybarometer aneroid barometer wind Jet Stream pressure gradient isobars Highs Lows pressure difference Coriolis effect friction air mass cyclones anticyclones
- 3. 3 Air mass- parcelof air with the same qualities (pressure & temperature) • Takes on characteristics of the area that formed it Air moves in two ways: -- VERTICALLY due to air pressure -- HORIZONTALLY due to tendency of moving from HIGH H to LOW L pressure areas (In N Hemisphere, L tends to move north and H tends to move SE)
- 4. 4 Air pressure: weightof air above, pressing down with gravity • Changes with elevation 50% of air lies below this altitude: VIDEO: How Heavy is Air? (3 min)
- 5. 5 MEASURING AIR PRESSURE Airpressure: ‘weight of air’; exerted in all directions • Mercury Barometer- • Inverted tube in a bath of Mercury; • Air pressure pushes down on the Mercury bath, causing the Mercury to go up the tube VIDEO: How does a barometer work? (5 min)
- 6. 6 Forecasting Weather • Pressurefalls: indicates storms & rain • Pressure rises: fair weather • Pressure steady: more of the same
- 7. 7 WIND Wind: horizontal differencesin air pressure; air moves from areas of high pressure to areas of low pressure VIDEO: Why does the wind blow? (3 min) Wind speed: anemometer- measures wind speed
- 8. 8 Wind Direction Prevailing winds-Where is the wind coming from? • In the US: prevailing winds are from West to East
- 9. 9VIDEO: The GulfStream Explained (5 min)
- 10. 10 WIND is influencedby: Pressure difference: Solar radiation unevenly heating atmosphere
- 11. 11 WIND is influencedby: Coriolis effect: Earth’s rotation affects movement of objects; deflects objects to the right in N Hemisphere Actual Movement Direction of Movement VIDEO: Coriolis Effect (3 min)
- 12. 12 WIND is influencedby: Friction: • Friction Layer: landforms slow air masses near the surface • Jet stream: high, fast moving air above the friction layer; West to East direction
- 13. 13 How do weshow Wind on a map? Start with AIR PRESSURE. Is it rising or falling? • pressure gradient- spacing of isobars show amount of pressure change over a distance How closely are the lines spaced? • Isobars- closer spaced isobars = steep pressure gradient = high winds LOW A B
- 14. 14 H = “heavy”,high pressure: L = “light”, low pressure LOW A B
- 15. 15 isobars: contour linesmeasuring air pressure
- 16. 16 HIGHS Highs- Anticyclones • Areasof high (heavy) pressure • Pressure increases from outer isobars towards center H H
- 17. 17 •Big Blue H •EXAMPLE:warm air mass stays low to the ground, pushing on the ground.) •At ground: swirling cool, dry air •Fair weather •Clockwise swirl in N Hemisphere “Hi! How are you?” arms HIGH PRESSURE SYSTEMS H anticyclone
- 18. 18 LOWS Lows- Cyclones • Areasof low (light) pressure • Pressure decreases from outer isobars toward center L L
- 19. 19 •Big Red L •EXAMPLE:warm air mass lifts and moves vertically, causing less pressure on the ground.) •At ground: warm, moist air, strong winds •Severe weather/ thunderstorms •Counter clockwise swirl in N Hemisphere Feeling “low” running away arms LOW PRESSURE SYSTEMS L L cyclone
- 20. 20 VIDEO High &Low Pressure (1:30) Air Pressure WS
- 21. 21 Patterns global winds frontalwedging Polar Air Circulation warm front Ferrel Air Circulation cold front Hadley Air Circulation middle latitude cyclones Polar Easterlies occluded front Westerlies stationary front NE Trade winds SE Trade winds anemometer prevailing winds El Nino La Nina Maritime mass Continental mass Polar mass Tropical mass humidity
- 22. 22 Air Masses m Maritime: originsover the ocean c Continental: origins over continents P Polar: low humidity T Tropical: high humidity
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- 25. 25 Air Masses ___ Label theAir Masses. Color warm masses red. Color cold masses blue. _________ ___ ______
- 26. 26 cool, rainy weather LAKES: make Snowy weather warm,wet weather warm, dry weatherwarm, wet weather cool, snowy weather cool, dry weather mP cP mP cT mT mT
- 27. 27 GLOBAL WINDS Because ofuneven heating of Earth, the atmosphere acts as a giant heat-transfer system to maintain balance Non-rotating Earth Model Rotating Earth Model 2 cell-convection Multi-cell convection
- 28. 28 LOW pressure LOW pressure LOWpressure HIGH pressure HIGH pressure Polar Air Circulation Ferrel Air Circulation Hadley Air Circulation Atmo 2 WS- complete with lecture
- 29. 29 LOW pressure LOW pressure LOWpressure HIGH pressure HIGH pressure Polar Air Circulation Ferrel Air Circulation Hadley Air Circulation Polar Easterlies Westerlies NE Trade winds SE Trade winds Atmo 2 WS- complete with lecture
- 30. 30 LOW pressure LOW pressure LOWpressure HIGH pressure HIGH pressure Atmo 2 WS- complete with lecture
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- 33. El Nino- partof GLOBAL WEATHER • Cold Peruvian current flows toward equator, allowing upwelling & good fishing • In December, warm waters replace the current, lasting for a few weeks, upsetting weather patterns; blocking upwelling; inland areas get more rain than usual 33VIDEO: El Nino 3 min
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- 35. 35 Front: boundary between twoair masses VIDEO: Weather for Pilots (5 min)
- 36. 36 WARM FRONT • Warmair moves into an area formerly covered by cooler air • Hard to move the cooler & denser air, so it slowly rides on top of it… Creates HEAVY (High) pressure • Associated with stable, fair weather, possible light rain if front remains for a few days Frontal Wedging
- 37. 37 Half circles… SMOOTH& SLOW Half circles on the side the front is moving Frontal Wedging
- 38. 38 COLD FRONT • Cold,dense air moves into a region occupied by warmer air • Forceful lifting of warm, wet air causes instability; thunderstorms & strong wind • Faster front because it’s denser Frontal Wedging
- 39. 39 Faster b/c denser Triangleson the side the front is moving Triangles… SHARP CUT & FAST Frontal Wedging
- 40. 40 STATIONARY FRONT • Whenair flow on either side is neither toward cold mass or warm mass • Stable • Sometimes, gentle precipitation Frontal Wedging
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- 42. 42 OCCLUDED FRONT • Whenan active cold front moves fast & overtakes an existing warm front • Wedges the warm air upwards causing heavy rain • Front moves slowly, so rains for several days Frontal Wedging
- 43. 43 OCCLUDED FRONT When acold front overtakes a warm front that was moving ahead of it. Frontal Wedging
- 44. 44 Middle Latitude Cyclones Largecenters of low pressure, moving West to East, causing stormy weather • between 30° and 60° latitude US WEATHER REMEMBER:
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- 46. 46 Anticyclone & Cyclone A= AWAY C = to CENTER
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- 48. 48 STORMS thunderstorm thunder lightning tornado vortex updraft Fujita Scale Tornado WarningSystem Saffir-Simpson Scale hurricane (typhoon, cyclone, tropical cyclone)
- 49. 49 STORMS Thunderstorm- storm generatinglightening &b thunder • 2,000 thunderstorms happening at any given time; highest number in the tropics (warm, humid) • Southeast US • Warm, humid air rises in an unstable environment VIDEO: The most lightning =struck place (3:40)
- 50. 50 TORNADO Tornado- violent windstorms,rotating column of air called a vortex • US: 770 tornadoes each year • Form in updraft of a thunderstorms
- 51. 51 VIDEO: Watch thebirth of a tornado 3 min NOT DOWNLOADED
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- 54. 54 Tri-State Tornado: March 18,1925 • killed 695, injured 2,027 • 300 miles • Missouri • Illinois • Indiana
- 55. 55 Tornado Warning System •Issued by National Weather Service Watch: conditions are favorable for a tornado Warning: a tornado has been spotted; seek shelter immediately VIDEO: How do tornadoes form (4 min)
- 56. 56 TORNADO SAFETY • Goto low ground: basement, ditch • Avoid windows • Leave mobile home • At school: follow the drill- interior hallway, cover head • Leave vehicle, find a low ditch, cover head AFTER: • Do NOT touch downed power lines or sharp objects • Stay out of heavily damaged buildings
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- 58. 58 HURRICANE Hurricane- whirling tropicalcyclones producing winds of at least 74 mph • Name is regional: • Hurricane • Typhoon • Cyclone • Tropical cyclone • Associated with storm surges and flooding • Occurrences seem to be increasing with global warming
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- 63. 63 VIDEO: Engines ofDestruction (6 min)
- 64. 64 Hurricane Katrina August 2005 •Extremely destructive and deadly Category 5 hurricane • 1,800 deaths • Struck Gulf of Mexico • Damage from central Florida to Eastern Texas • New Orleans: sits below sea level & was catastrophically flooded VIDEO Katrina (5 min)
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- 66. 66 HURRICANE SAFETY • Easilypredicted, so pay attention to weather forecasts • Prepare: food, water, flashlight, first aid kit • Stay indoors during hurricanes • Heed local warnings; if an evacuation is called, LEAVE before the hurricane • Know evacuation routes
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- 68. 68 STATION MODELS VIDEO TUTORIAL(12 min) feather points in wind direction
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- 71. 71 •Big Red L •EXAMPLE:warm air mass lifts and moves vertically, causing less pressure on the ground.) •At ground: warm, moist air, strong winds •Severe weather/ thunderstorms •Counter clockwise swirl in N Hemisphere Feeling “low” running away arms LOW PRESSURE SYSTEMS L L cyclone
- 72. 72 •Big Blue H •EXAMPLE:warm air mass stays low to the ground, pushing on the ground.) •At ground: swirling cool, dry air •Fair weather •Clockwise swirl in N Hemisphere “Hi! How are you?” arms HIGH PRESSURE SYSTEMS H anticyclone
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