1. Chapter 2 – Weather factors
2.1 Energy in the Atmosphere

2. Think about it…
Where does the energy of our Earth come from?

3. Electromagnetic Radiation
Nearly all of the energy in Earth’s atmosphere comes from the sun
Energy travels as electromagnetic waves.
Electromagnetic waves are a form of energy that can move through the vacuum of space.
Electromagnetic waves are classified by their wavelengths

4. Electromagnetic Radiation
The direct transfer of energy by electromagnetic waves is called radiation.
Most energy from the sun reaches the Earth in the form of infrared radiation, visible light, and ultraviolet radiation.

5. Wavelengths

6. Analyze the picture …take 1 minute and discuss with a partner…
Why do we see different colors?
How do color and wavelength compare?
Which colors have the shortest wavelengths?

7. Which colors have the longest wavelengths?
What type of radiation has wavelengths that are shorter than visible light? Longer?

8. Were you right?
Why do we see different colors? Because of different wavelengths
How do color and wavelength compare? Short and long wavelengths result in different colors
Which colors have the shortest wavelengths? Blue and Violet
Which colors have the longest wavelengths? Red and orange
What type of radiation has wavelengths that are shorter than visible light? Longer? Ultraviolet radiation, x-rays and gamma rays / infrared radiation and radio waves

9. Visible Light: ROY G BIV
Infrared Radiation – wavelengths are longer than red light.
The color of visible light with the longest wavelength is Red.
The color of visible light with the shortest wavelength is Blue.
Ultra-violet Radiation – wavelengths are shorter than violet light

10. Think about it…
What role does our atmosphere play in the ability of energy to reach our Earth?

11. Energy Water Vapor and Carbon Dioxide absorb some infrared radiation
Some of the sun’s rays are reflected by clouds, dust, and molecules of gases called scattering.
Gas molecules scatter short wavelengths of blue and violet more than red and orange making the daytime sky look blue.

13. Energy The ozone layer absorbs most of the ultraviolet radiation
Green house effect- natural process by which gas holds heat in the air.
Gases include water vapor, carbon dioxide, methane, and other gases that form a blanket around earth.
Some energy reaches the surface and warms the land and water

14. Energy in the atmosphere

16. What are your thoughts?
What might conditions on Earth be like without the Greenhouse effect?

17. Chapter 2 – Weather factors
2.2 Heat Transfer

18. Energy and Temperature
Thermal energy is the total energy of MOTION of the molecules in a substance.
Temperature is an average amount of energy of motion of the molecules in a substance.

19. Hot = fast moving molecules Cold = slow moving molecules

20. Measuring Temperature
Thermometers are used to measure temperature
Liquids expand when they are heated and contract when they are cooled
Temperature is measured in units called degrees. (Celsius or Fahrenheit)
Water freezes at 0ºC and boils at 100ºC

21. How Heat is Transferred
Heat is the energy transferred from a hotter object to a cooler one.

22. Heat is transferred 3 ways
Radiation is the direct transfer of energy by electromagnetic waves.
ex) feeling the warmth of the fire on your skin

23. Heat is transferred 3 ways
Conduction is the direct transfer of heat from one substance to another substance ( must be touching)

24. Heat is transferred 3 ways
Convection is the transfer of heat by the movement of a fluid.
ex) heating up soup in a pan.

25. Heat Transfer in the Troposphere

26. A comparison…

27. Chapter 2 - Weather factors
2.3 Winds

28. What Causes Winds?
Wind is the horizontal movement of air from an area of high pressure to an area of lower pressure.
All winds are caused by differences in air pressure.
Differences in air pressure are caused by unequal heating of the atmosphere.

29. Measuring Wind Wind vanes are used to determine wind direction.
The name of a wind tells you where the wind is coming from.
Anemometers are used to measure wind speed.
Wind over your skin removes body heat.
The increased cooling that a wind can cause is called
the wind- chill factor.

30. Local Winds Winds that blow over short distances.
Caused by unequal heating of Earth’s surface within a small area.
Usually occurs near a body of water.

31. Local Winds
Land heats up faster during the day, warming the air above it. Warm air expands and rises, creating a low-pressure area. Cool air blows inland from the water to replace the warm air.

32. Local Winds
sea breeze – a wind that blows FROM an ocean or a lake onto land
land breeze – the flow of air FROM land to a body of water

33. Monsoons
Sea and land breezes over a large region that change direction with the seasons

34. Global Winds
Winds that blow steadily from specific directions over large distances.
Caused by unequal heating of Earth’s surface. (equator vs. poles)
Global Convection Currents cause wind at Earth’s surface to blow from the poles to the equator.
Higher in the atmosphere, air flows away from the equator and toward the poles.

35. Global Winds
The movement of air between the equator and the poles produces global winds.
Coriolis Effect – winds do not blow in straight lines because the Earth is spinning underneath them. This causes the winds to curve.
In the NORTHERN HEMISPHERE – the Coriolis Effect causes our wind to turn towards the right. It is the opposite in the southern hemisphere.

36. Jet Stream Bands of high-speed wind about 10km above Earth’s surface.
They blow from west to east at about km per hour

37. Global Wind Belts DOLDRUMS: Caused by rapid warming of air
near the equator
air is almost always warm so there are little to no winds

38. Global Wind Belts HORSE LATITUDES:
Caused when air from equator stops moving towards poles and sinks
Latitude is the distance from the equator, measured in degrees
30º north and south latitudes, Calm air

39. Global Wind Belts
TRADE WINDS:
Caused when cold air over the horse latitudes sinks and produces a high pressure region
Blow towards the equator from about 30º north and south

40. Global Wind Belts
PREVAILING WESTERLIES: Caused when winds that blow toward the poles are turned toward the east by the Coriolis effect.
Between 30º and 60º north and south latitudes.
Blow FROM West to East
They play an important role in the United State’s weather

41. Global Wind Belts
POLAR EASTERLIES:
Caused when cold air near the poles sinks and flows back toward lower latitudes
They meet the prevailing westerlies at about 60º north and south latitudes at the Polar Front.
The polar front has a major effect on weather changes in the US.

44. 2.4 Water in the Atmosphere
Chapter 2
2.4 Water in the Atmosphere

45. Water cycle- movement of water between the atmosphere and earth’s surface

46. 2-4 Water in the Atmosphere
Evaporation – the process by which water molecules in liquid water escape into the air as water vapor.

47. Humidity Humidity – a measure of the amount of water vapor in the air.
Relative Humidity – the percentage of water vapor in the air compared to the maximum amount the air could hold.
Used on weather reports!

48. Measuring Relative Humidity
Relative humidity can be measured using a psychrometer.
A psychrometer has two thermometers, a wet bulb and a dry bulb.
The wet bulb is covered with a damp fabric.
Evaporation cools the wet bulb.
Relative humidity can be found by comparing the temperature of the wet and dry bulb thermometers.

51. A problem…
What would the relative humidity be if your dry bulb showed a temperature of 60ºF and the wet bulb showed a temperature of 54ºF? ( a difference of 6º)

52. Answer
60 – 54 = 6
Dry bulb temp is 60
Relative Humidity = 68%

53. How Clouds Form
Clouds of all kinds form when water vapor in the air becomes liquid water or ice crystals.
Condensation – the process by which molecules of water in the air become liquid water
Cold air can hold less water vapor than warm air
As air cools, the amount of water vapor it can hold decreases
Some of the water vapor in the air condenses to form droplets of liquid water

54. How Clouds Form
Dew Point – the temperature at which condensation begins
For water to condense, tiny particles must be present so the water has a surface on which to condense
Particles are usually salt crystals, dust from soil, and smoke.
Dew is water than condenses above the freezing point and land on a solid surface such as a blade of grass.
Frost is ice that has been deposited directly onto a surface that is below the freezing point.
Clouds form whenever air is cooled to its dew point

55. Types of Clouds Meteorologists classify clouds into three main types:
cumulus
stratus
cirrus.

56. Types of Clouds
Cumulus clouds look like fluffy, rounded piles of cotton that indicate nice weather when not tall

57. Cirrocumulus-rows of cotton balls indicating a storm is on the way.

58. Cumulonimbus clouds often produce thunderstorms

59. Stratus clouds form in flat layers that can thicken and can produce drizzle, rain, or snow (nimbostratus)

60. Cirrus clouds are wispy and feathery and only form at high altitudes
Cirrus clouds are wispy and feathery and only form at high altitudes. (made of ice crystals)

61. Altostratus and Altocumulus are clouds that form 2-6km above earth’s surface.
Middle level clouds

62. Clouds that form at or near the ground are called fog
Clouds that form at or near the ground are called fog. Form when the ground cools at night after a warm humid day.

63. Chapter 2 Weather
2.5 Precipitation

64. Precipitation
Precipitation is any form of water that falls from clouds and reaches Earth’s surface

65. Types of Precipitation
Common types of precipitation include rain, sleet, freezing rain, hail and snow.
Rain – most common type of precipitation, drops of water are at least 0.5mm in diameter, smaller drops are mist and drizzle which usually fall from nimbostratus clouds
Sleet – raindrops freeze as they fall, ice particles are smaller than 5mm in diameter

66. Freezing Rain – raindrops freeze when they touch a cold surface
Hail – round pellets of ice larger than 5mm in diameter, only forms inside cumulonimbus clouds during thunderstorms
Snow – water vapor in cloud is converted directly into ice crystals called snowflakes, all have six sides or branches

67. Measuring Precipitation
Meteorologist measure rainfall with a rain gauge.
Rain gauge – an open-ended can or tube that collects rainfall.

68. Controlling Precipitation
Droughts – long periods of unusually low precipitation
In cloud seeding, tiny crystals of dry ice (solid carbon dioxide) and silver iodide are sprinkled into clouds from airplanes.
The super cooled water droplets in the cloud can then condense around the silver iodide particles.
Dry Ice cools the water even more so it freezes without a surface to condense on.