2. Atmosphere

3. Solar Energy as Radiation Figure 1.1 Nearly 150 million kilometers separate the sun and earth, yet solar radiation drives earth's weather.

4. Earth's Atmosphere The atmosphere is a thin layer of air that protects the Earth’s surface from extreme temperatures and harmful sun rays Figure 1.2 Thin Gaseous envelope

5. Composition of Atmosphere (Mixture of gases, solids, and liquids) Early atmosphere was much different than today Volcanoes produced nitrogen and carbon dioxide, but little oxygen More than 2 billion years ago, early organisms began producing oxygen Eventually, oxygen formed an ozone layer that protected Earth from harmful rays Green plants and diverse life forms developed

6. Atmospheric Gases (Mixture of gases, solids, and liquids) Nitrogen - 78% Oxygen - 21% Water Vapor – 0 to 4% Used for clouds and precipitation Carbon Dioxide -.037% Keeps Earth warm and is used by plants to make food Argon -.93% Traces of neon, helium, methane, krypton, xenon, hydrogen, and ozone

7. Atmospheric Gases (Mixture of gases, solids, and liquids) Atmosphere is changing with the introduction of pollutants; increasing human energy use is increasing the amount of carbon dioxide Pollutants mix with oxygen and other chemicals to form smog Aerosols include solids such as dust, salt, and pollen Liquids include water droplets and droplets from volcanoes

8. Five Layers of the Atmosphere

9. Lower Layers of Atmosphere Troposphere: lowest layer – extends up to 10km; contains 99% of the water vapor and 75% of the atmospheric gases The troposphere is the first layer above the surface and contains most clouds and half of the Earth's atmosphere.troposphere Weather occurs in this layer. Most of the layer’s heat is from Earth Temperature cools about 6.5 degrees Celsius per kilometer of altitude.

10. Lower Layers of Atmosphere Stratosphere – directly above troposphere, extending from 10 km to about 50 km above Earth’s surface Portion of the upper layer contains high levels of a gas called ozone Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun. stratosphere

11. Upper Layers of Atmosphere Mesosphere – extends from the top of the stratosphere to about 85 km above Earth Coldest layer with little ozone Meteors or rock fragments burn up in the mesosphere.mesosphere Ionosphere here – layer of charged particles

12. Upper Layers of Atmosphere Thermosphere – thickest atmospheric layer found between 85 km and 500 km above Earth’s surface The thermosphere is a layer with auroras, known for its high temperatures.thermosphere Warms as it filters out X-rays and gamma rays from the Sun Ionosphere here, too – help carry radio waves.

13. Upper Layers of Atmosphere Exosphere - The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.exosphere Outer layer where space shuttle orbits.

14. Layers of Atmosphere

15. Atmospheric Pressure Molecules closer to the surface are more densely packed (at higher pressure) together than those higher in the atmosphere because of the mass of gases pressing down on them from higher in the atmosphere

16. Temperature in atmospheric layers The troposphere is warmed primarily by the Earth’s surface; temperature decreases as altitude increases in this layer. Temperatures increase as altitude increases in the stratosphere, particularly in the upper portion – ozone Temperatures decrease with altitude in the mesosphere Thermosphere and exosphere are the first to receive Sun’s rays, so they are very hot

17. The Ozone Layer About 19 km to 48 km above Earth in the stratosphere (90%) and troposphere (10%). Layer of 3-atom molecules that protects the Earth from the Sun’s harmful ultraviolet radiation Life depends on the ozone! Pollutants called chlorofluorocarbons (CFCs) are destroying the ozone CFCs are used in refrigerators, air conditioners, aerosol sprays, and foam packaging ~ if products leak, CFCs enter atmosphere Ozone layers has a large hole over Antarctica and a smaller one over the North Pole

18. Some of the Sun’s energy coming through Earth’s atmosphere is reflected or absorbed by gases and/or clouds in the atmosphere.

19. Greenhouse Effect Solar energy that is absorbed by the Earth’s land and water is changed to heat that moves/radiates back into the atmosphere (troposphere) where gases absorb the heat, a process known as the greenhouse effect.

20. Greenhouse Animation

21. Global Warming Effects of Global Warming on Wildlife Global Warming VIDEO Global Warming VIDEO #2

22. Heat Energy that flows from an object with a higher temperature to an object with a lower temperature Heat is transferred through the atmosphere by: Radiation:energy that is transferred in the form of rays or waves Conduction:energy that is transferred when molecules bump into each other Convection:energy that is transferred by flow of material Molecules move closer together, making air more dense, and air pressure increases Cold air sinks, pushing up warm air, which then cools and sinks, pushing up more warm air

23. Water Cycle – water makes up 70% of Earth’s surface!!

24. Water Cycle Video LinkVideo Link Water moves back and forth between Earth’s atmosphere and surface Energy from the sun causes water to evaporate from the hydrosphere and rise as vapor Sun provides water cycle’s energy Water on the surface absorbs heat and evaporates, entering the atmosphere Condensation – water vapor changes back into liquid Clouds of water become heavy and water falls to Earth as precipitation The cycle repeats itself continuously

25. Rain & Drizzle- m ost common type of precipitation. Freezing Rain- drizzle from stratus clouds. Freezing Rain- r aindrops freeze when they hit the ground. Sleet- raindrops that freeze before they hit the ground. Waters 3 States VideoWaters 3 States Video 6:52

26. snow- as ice grows and merges into clouds they form snowflakes. hail- is the largest type of precipitation. Lumps or balls of ice that fall from cumulonimbus clouds in warm weather. The Water Cycle and Clouds Video The Water Cycle and Clouds Video 15:01 The Sun, Water Cycle, & Climate VideoThe Sun, Water Cycle, & Climate Video 2:37

28. Let’s take a look at the weather picture and why we have weather!

29. What is Weather? State of the atmosphere at a specific time and place Includes such conditions as air pressure, wind, temperature, and moisture in the air Temperature is a measure of air molecule movement Sun’s energy causes air molecules to move rapidly; temperatures are high and it feels warm When less of the Sun’s energy reaches air molecules, they move less rapidly and it feels cold

30. What is Weather? Energy is transferred between fast-moving molecules and slower-moving molecules CONDUCTION – transfer of energy when molecules collide CONVECTION – occurs when warm air rises and cool air sinks; it’s the transfer of heat, usually in liquids or gases

31. If we were to pick one term to help explain why we have weather, what do you think would be a good word? You might pick heat or sun….but another good choice would be Convection

32. After the atmosphere is warmed by radiation and conduction, the heat is transferred throughout the atmosphere by convection. Since warmed air has more space between the molecules, it’s less dense and rises Cooled air is more dense and tends to sink In general, air near the equator tends to rise and air near the poles tends to sink

33. Take a look at this!

34. Notice the band of clouds around the equator ? This is the ITCZ or inter tropical convergence zone

35. Why do you think there is this band of clouds near the equator?

36. Did you figure it out? Warm, moist air in the tropics rises Cold air can hold less moisture than warm air As the moist air rises, it condenses and forms clouds!

37. Now What? Ok, so we know that the weather moves around on these highways and that warm air rises and cold air sinks. But why is it sunny one day, and rainy the next?

38. Let’s take another look at the weather map Notice that there are H ’s and L ’s on the map There are also blue lines with spikes and red lines with half circles Let’s take a closer look!

39. AIR PRESSURE Air weight that varies over Earth’s surface Warmer air is less dense and exerts less pressure Cooler air is more dense and exerts more pressure

40. High Pressure Areas When cooler air sinks and is warmed, the air can hold more moisture This usually means sunny skies Winds tend to move clockwise around a high

41. Low Pressure Areas When warm air rises and is cooled, the air can not hold as much moisture Often, these areas are associated with precipitation and stormy weather Winds tend to move counter clockwise around the low

42. So, if you see a big H on the weather map over the area you live, you can expect fair weather

43. When you see a big L in your area, there will probably be stormy weather

44. These highs and lows move or less along the jet stream and bring us our weather changes

45. Humidity The amount of water vapor in the air Temperature affects how much moisture is in the air - warmer air can hold more water vapor, tending to make it more humid Relative humidity – the amount of water vapor in the air compared to what it can hold at a specific temperature When air cools, it can’t hold as much water vapor, so the water vapor condenses to liquid or forms ice crystals Dew point – the temperature at which air is saturated and condensation forms

46. Clouds Form when air rises, cools to its dew point, and becomes saturated Shape and height of clouds vary with temperature, pressure, and water vapor in atmosphere

47. Clouds Shape Stratus-smooth, even sheets or layers at low altitudes Cumulus-puffy, white clouds, often with flat bases Cirrus-high, thin, white feathery clouds made of ice crystals Height Cirro – high clouds Alto – middle-elevation clouds Strato – low clouds Nimbus clouds are dark and so full of water that sunlight can’t penetrate them

48. Clouds LOW CLOUDS – form at 2,000 m or less in altitude Cumulus – puffy clouds formed when air currents rise and carry moisture Stratus – layered dull, gray sheets that can cover the entire sky Nimbostratus – low, dark, thick layers that hide the Sun

49. Cumulus · Clouds formed at medium or low elevation. · Cumulus clouds are puffy with flat bottoms. · When cumulus clouds are white they often signal fair weather, but when they are darker, they may signal rain or thunderstorms.

50. Stratus Clouds formed at medium or low elevation; spread out layer upon layer covering a large area As stratus clouds thicken, precipitation usually occurs over that area.

51. Cumulus

52. Stratus

54. Clouds MIDDLE CLOUDS – form between 2,000 m and 8,000 m in altitude Most are layered Names have alto- prefix (altocumulus and altostratus) Can produce light precipitation

57. Clouds HIGH AND VERTICAL CLOUDS Cirrus – wispy, high-level clouds Cirrostratus – high, layered clouds that can cover the sky Cumulonimbus – known as thunderstorm clouds; produce heavy precipitation

58. Cirrus Clouds formed at high elevations; wispy clouds usually consisting of ice crystals that signal fair weather or may also signal an approaching warm front.

59. Cirrus

64. Fog

66. Cloud Cover Symbols You will often see the circles drawn on a weather map

67. Air Movement Wind: Movement of air from one temperature or pressure area to another Different areas of Earth receive different amounts of the Sun’s energy Equator’s warm air, being less dense, is pushed upward by denser, colder air Poles’ cold air, being more dense, sinks and moves along Earth’s surface CORIOLIS EFFECT: spinning of the Earth causes moving air to turn to the right in the northern hemisphere and to the left in the southern hemisphere

68. Global Winds Wind patterns, caused by convection currents combined with the Coriolis effect, of Earth that affect the world’s weather Near equator, very little wind and daily rain patterns called the doldrums Surface winds: Between equator and 30 degrees N and S latitude are steady trade winds Between 30 and 60 degrees N and S latitude, the westerlies blow in opposite direction from the trade winds. The polar easterlies blow from northeast to southwest near the north pole and from southeast to northwest near the south pole

69. Global Winds Equatorial doldrums TRADEWINDS

70. The Weather Highways The rotation of the earth creates the Coriolis effect. The Coriolis effect causes the air and water to be deflected to the right north of the equator. This creates global weather highways

71. The Westerlies Because of our latitude, most of our weather comes from the west Looking at the weather map, what type of weather might we expect? What type of weather might we expect in a few days?

72. Let’s break for a short review 1.Transfer of heat in liquids or gases_____ 2. _____ air is dense and tends to sink. 3. Band of clouds found around the equator______ 4. Cold air holds _____ moisture than warm air 5. The Coriolis effect causes the air and water to be deflected to the _____ of the equator

73. How did you do? 1. CONVECTION 2. COLD 3. ITCZ 4. LESS 5. RIGHT

74. Fronts and Air Masses Because air and moisture move in the atmosphere, weather is constantly changing Air pressure – measured by barometer An air mass is a large body of air whose temperature and moisture are fairly similar at a given altitude; properties like the part of Earth’s surface over which it formed Fronts are boundaries separating different air masses – clouds, precipitation, and storms occur at frontal boundaries There are four different air masses that affect the United States

75. The Air Masses cP( continental polar) : cold, dry stable cT( continental tropical) : hot, dry, stable air aloft, unstable at the surface mP( maritime polar) : cool, moist, unstable mT( maritime tropical) : warm, moist, unstable

76. This map shows the air mass source regions and there paths

77. Warm Fronts A warm front is warm air displacing cool air Shallow leading edge warm air must “overrun” cold air These are usually slow moving Widespread precipitation develops!

78. 2. Warm Front: The zone where warm air is replacing colder air In U.S., warm fronts usually move from southwest to northeast Air gets more humid after a warm front moves through

79. Cold Fronts Cold air advances into region of warm air Intensity of precipitation greater, but short lived Clearing conditions after front passes Usually approaches from W or NW Temperature drops; narrow band of violent storms!

80. 1. Cold Front: The zone where cold air is replacing warmer air In U.S., cold fronts usually move from northwest to southeast Air gets drier after a cold front moves through

81. Stationary Fronts Surface positions of the front do not move Often a region of clouds and precipitation

82. 3. Stationary Front: When either a cold or warm front stops moving When the front starts moving again it returns to either being a cold or warm front

83. Occluded Fronts Cold front overtakes warm front Involves three air masses of different temperatures Often found close to the low pressure center Cloudy weather with precipitation!

84. 4. Occluded Front: Formed when a cold front overtakes a warm front This occurrence usually results in storms over an area In U.S., the colder air usually lies to the west MENU

85. Ready for a little quiz? Here we go!

86. 1. Winds in a low pressure system move _____ around the low

87. 2. What type of front can be found close to point D ?

88. 3. Which of these fronts would you expect to have greater precipitation, but be short lived as the front passes?

89. 4. Give the name of the air mass that would have the following characteristics : cool, moist, unstable

90. 5. That important weather word that refers to the transfer of heat

91. 6. In general, air near the equator tend to_____ ( rise or fall )

92. 7. It causes air and water to be deflected to the right north of the equator

93. 8. Which of the weather highways usually controls our weather

94. 9. Warm air holds ( more or less ) moisture than cold air

95. 10. If there is a big H on the weather map where you live, would you expect fair or stormy weather

96. How did you do? Let’s check the answers!

97. Answers 1. Counterclockwise 8. Westerlies 2. Cold 9. More 3. Cold 10. Fair 4. Maritime polar (mP) 5. Convection 6. Rise 7. Coriolis

98. Anemometer- A tool used to measure wind speed in miles per hour. Wind vane · A tool used to measure wind direction. · Sometimes referred to as a wind-weather vane or a wind sock. · Wind direction is described by the direction from which the wind is blowing. Thermometer - A tool used to measure air temperature in degrees Fahrenheit or Celsius.

99. Sling Psychrometer- A two-thermometer instrument also referred to as a wet-dry bulb used to measure relative humidity (the amount of water vapor in the air). Temperatures readings are converted using a relative humidity table. Weather Instruments Video 1Weather Instruments Video 1 15:01 Weather Instruments Video 2Weather Instruments Video 2 19:41

100. Barometer- A tool used to measure air pressure in inches of mercury or millibars (mb). Rain gauge- A tool used for measuring the amount of precipitation in inches or centimeters.

102. MENU

103. Reading a weather map ISOBAR= connects areas of equal pressure BAR comes from BARometric pressure

104. Reading a weather map... Isotherm: Connects areas of equal temperature; therm means temperature

106. Information found on a station model can include cloud cover, temperature (85°F), wind direction and speed, precipitation (snow, rain), or barometric pressure (1002 mb). Station models from specific locations provide information that can also be used to predict weather patterns.

107. Weather Station (not on the TV) Weather conditions at specific location Current Conditions!!

108. Satellites · Satellite images are used for seeing cloud patterns and movements. · For example, hurricane clouds and movement can be observed using satellite images. Radar · Radar images can be used to detect cloud cover, rainfall or storm location, intensity, and movement, as well as the potential for severe weather (for example, hurricanes or tornadoes).

109. Severe Weather Thunderstorms occur inside warm, moist air masses and at fronts Warm, moist air is forced rapidly upward, where it cools and condenses Strong updrafts of warm air and sinking, rain-cooled air cause strong winds

110. Lightning Movement of air inside a storm cloud causes parts of the cloud to become oppositely charged Current flows between the regions of opposite electrical charge, forming a lightning bolt Thunder – lightning superheats the air, causing it to expand rapidly and then contract, forming sound waves

111. Tornado Violent, whirling wind that moves in a narrow path over land

112. Hurricane Large, swirling, low-pressure system that forms over tropical oceans Heat energy from moist air is converted to wind that can reach speeds of 250 km/h

113. Blizzard A winter storm with strong winds, cold temperatures, and low visibility, that lasts more than three hours

114. Severe Weather Safety A National Weather Service WATCH means conditions are favorable for severe weather to develop A warning means that severe weather conditions already exist Meteorologists study and predict weather National Weather Service makes weather maps and issues watches and warnings