Chapter 2 – Weather factors

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 https://www.youtube.com/watch?v=l4yg4HTm3uk

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? Violet • Which colors have the longest wavelengths? Red 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- aform of electromagnetic radiation that is perceivable to human beings and is seen in the colors of the rainbow • 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 violet. • Ultra-violet Radiation – wavelengths are shorter than violet light

10. Wave diagram Crest – the top of a wave Trough – the bottom of a wave Wavelength – the distance from crest to crest or trough to trough in a wave Frequency – the number of wavelengths that pass a given point in a set amount of time Origin – the center/start or midpoint of a wave Amplitude – the distance from the origin to the crest or the trough of a wave Speed of light – c- the rate at which all forms of electromagnetic radiation travel through a vacuum = 3.0x108 m/s

11. Wavelength and frequency are inversely proportional so…… High frequency = Short Wavelength Low frequency = Long Wavelength

12. Energy • Water Vapor and Carbon Dioxide absorb some infrared radiation • Some of the sun’s rays are reflectedby 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.

14. 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

15. Energy in the atmosphere

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

18. Chapter 2 – Weather factors 2.2 Heat Transfer

19. 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.

20. Hot = fast moving moleculesCold = slow moving molecules

21. 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

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

23. 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

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

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

26. Heat Transfer in the Troposphere

27. A comparison…

28. Chapter 2 - Weather factors 2.3 Winds

29. 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.

30. 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.

31. 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.

32. 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 toreplace the warm air.

33. 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

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

35. 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.

36. 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.

37. Jet Stream • Bands of high-speed wind about 10km above Earth’s surface. • They blow from west to east at about 200-400 km per hour

38. 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

39. 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

40. 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

41. 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

42. 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.

45. Chapter 2 • 2.4 Water in the Atmosphere

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

47. 2-4 Water in the Atmosphere • Evaporation – the process by which water molecules in liquid water escape into the air as water vapor.

48. 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!

49. 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.