1. Earth’s Atmosphere

2. Integrated Science Do Now
Explain how oxygen levels increased in early Earth’s atmosphere

3. Solar Energy as Radiation
At it’s Surface, the earth maintains an average temp of 59F
With a wide range of temperature readings
-121F during the Antarctica night
122F in deserts
Figure 1.1
Nearly 150 million kilometers separate the sun and earth, yet solar radiation drives earth's weather.

4. What is the average temperature on Earth?
Do Now
What is the average temperature on Earth?

5. Average temperature is about 61 degrees farenheit

6. Earth's Atmosphere
The atmosphere is a thin layer of air that protects the Earth’s surface from extreme temperatures and harmful sun rays

7. Composition of Atmosphere (Mixture of gases, solids, and liquids)
Early atmosphere was much different than today
Volcanoes produced nitrogen and carbon dioxide.
More than 2 billion years ago, early organisms began producing oxygen through photosynthesis

8. Atmospheric Gases Nitrogen - 78% Oxygen - 21% Water Vapor – 4%
Carbon Dioxide %
Keeps Earth warm and is used by plants to make food

9. Atmospheric Gases (Mixture of gases, solids, and liquids)
Atmosphere is changing with the introduction of pollutants.
Pollutants mix with oxygen and other chemicals to form smog.
Liquids include water droplets and droplets from volcanoes

10. Smog in Beijing, China

12. Atmospheric Layers: From the Ground Up
Troposphere
Stratosphere
Mesosphere
Thermosphere
Exosphere

13. Five Layers of the Atmosphere

14. Lower Layers of Atmosphere
The troposphere is the first layer above the surface and contains half of the Earth's atmosphere.
Temperature cools about 6.5 degrees Celsius per kilometer of altitude.

15. Troposphere Troposphere is the lowest layer of Earth’s atmosphere.
Contains 99% of the water vapor.
Contains 75% of the atmospheric gases.
Weather occurs in this layer.

16. Stratosphere Directly above troposphere.
Reaches about 40 miles above Earth’s surface.
Ozone Layer found here.
Ozone absorbs harmful UV radiation.
Aircraft fly in the stratosphere because it is very stable.

17. Mesosphere
Extends from the top of the stratosphere to about 75 miles above Earth
Coldest layer.
Meteors burn up here.
Contains the Ionosphere which allows radio waves to travel.

18. Thermosphere
Thickest layer found between 75 and 450 miles above Earth’s surface.
Aururas occur here: Formed by solar radiation colliding with magnetic field.
Extremely high temperatures caused by X-rays and gamma rays from the Sun.

19. Exosphere The atmosphere this and merges into space.
Upper limit of our atmosphere.
Space shuttle and weather satellites orbit here.

20. Layers of Atmosphere

21. 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

22. 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

23. Environmental Science: Do Now
What is the Ozone Layer?
Where is it located specifically?
Why is it beneficial to us?

24. The Ozone Layer Found in the stratosphere (90%) and troposphere (10%).
Ozone is a molecule made of 3 oxygen atoms.
Protects the Earth from ultraviolet radiation
Life depends on the ozone!

25. Ozone Layer Concerns
Pollutants called chlorofluorocarbons (CFCs) are destroying the ozone
CFCs are used in refrigerators, air conditioners, aerosol sprays, and foam packaging.
Ozone layers has a large hole over Antarctica and a smaller one over the North Pole

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

27. Greenhouse Effect
Solar energy that is absorbed by the Earth is converted to heat.
Heat radiates back into the troposphere where it is absorbed by gases.

28. Greenhouse Animation

29. Heat
Heat is the transfer of kinetic energy from one object to another.
Heat increases the movement of molecules.
Ex: Rubbing your hands together

30. Heat Transfer in the Atmosphere
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 in circular patters. Ex: warm air rises, cool air sinks.

31. Atmosphere Diagram
Draw and label a diagram of Earth’s Atmosphere. Use colored pencils. Be Neat.
Include: Altitude, Temperature Range, Composition, and any other pertinent information as to what occurs in each layer.
For example: Meteors burn up in Mesosphere…

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

33. Water Cycle
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

34. Precipitation Rain & Drizzle- most common type of precipitation.
Freezing Rain- drizzle from stratus clouds.
Freezing Rain- raindrops freeze when they hit the ground.
Sleet- raindrops that freeze before they hit the ground.
Waters 3 States Video 6:52

35. Precipitation
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 Sun, Water Cycle, & Climate Video 2:37
The Water Cycle and Clouds Video 15:01

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

38. 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

39. 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

40. You might pick heat or sun….but another good choice would be
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

41. 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

42. Take a look at this!

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

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

45. 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!

46. 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?

47. 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!

48. 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

49. 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

50. 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

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

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

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

54. 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

55. 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

56. 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

57. 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

58. Clouds 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.

59. Clouds
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.

60. Cumulus

61. Stratus

62. Nimbo-stratus clouds

63. 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

64. Alto-cumulus clouds

65. Alto-stratus Clouds

66. 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

67. Clouds
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.

68. Cirrus

69. Cumulo-nimbus
Clouds
aka:
Thunderheads

70. Cirro-cumulus clouds

73. Fog

74. Fog

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

76. Do Now: What does the term albedo mean?
Briefly describe how the Greenhouse Effect works.

77. 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

78. 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

79. Global Winds
TRADEWINDS
Equatorial doldrums
TRADEWINDS

80. 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

81. 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?

82. 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

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

84. 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

85. 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

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

87. 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!

88. Warm Front
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

89. 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!

90. Cold Front
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

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

92. Stationary Front
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

93. 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!

94. Occluded Front
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

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

96. 1.
Winds in a low pressure system move _____ around the low

97. 2.
What type of front can be found close to point D ?

98. 3.
Which of these fronts would you expect to have greater precipitation, but be short lived as the front passes?

99. 4.
Give the name of the air mass that would have the following characteristics:
cool, moist, unstable

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

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

102. 7.
It causes air and water to be deflected to the right north of the equator

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

104. Warm air holds ( more or less ) moisture than cold air9.
Warm air holds ( more or less ) moisture than cold air

105. 10.
If there is a big H on the weather map where you live, would you expect fair or stormy weather

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

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

108. Weather Tools 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.

109. Weather Instruments Video 1 15:01 Weather Instruments Video 2 19:41
Weather Tools
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 1 15:01
Weather Instruments Video 2 19:41

110. Weather Tools
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.

111. Weather Map Symbols

112. MENU

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

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

115. Station Model

116. Station Models
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.

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

118. Satellites & Radar 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).

119. 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

120. 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

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

122. 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

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

124. 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