1. Structure and Temperature
The Atmosphere
Structure and Temperature

2. Atmosphere Characteristics
Most important measurable properties
Air Temperature
Humidity
Type of Precipitation
Amount of Precipitation
Air Pressure
Speed of Wind
Direction of Wind

3. Weather VS Climate Weather
Conditions of the atmosphere at a given time and place
The day to day changes
Climate
Observations of weather that have been collected over many years
Describes a place or region

4. Composition of the atmosphere
Wasn’t always like it is now
4.6 billion years ago was made of gases from volcanic eruptions
Oxygen started gathering around 2.5 billion years ago
Continuously exchanges material with oceans and plant life

5. Major components of atmosphere
Varies from time to time and place to place
99% Nitrogen and Oxygen
.93% Argon
.039% CO2

6. Variable Components 1. Water Vapor
Source of all clouds and precipitation
Absorbs heat given off by Earth
Absorbs solar energy

7. Variable Components 2. Dust Particles
Large particles don’t stay in the air for long
Microscopic particles travel for miles
Sea salts from breaking waves
Fine soil blown into air
Smoke and soot from fires
Pollen and other microorganisms
Ash and dust from volcanic eruptions

8. Variable Components 3. Ozone (O3)
Concentrated in layer 10-50km above Earth’s surface
Near earth we have O2, but when it rises it absorbs UV radiation and splits into O
Ozone formed when single O atoms collide with O2 atoms
Ozone layer important to us
Blocks UV rays

9. Human Influence Primary Pollutants
Emitted directly from identifiable source

10. Human Influence Secondary Pollutants Not emitted directly in air
Form when primary pollutants mix in atmosphere
Sulfur dioxide enters atmosphere
Reacts with oxygen gas
Produces Sulfur Trioxide
Combines with water to produce acid rain

11. Human Influence Secondary Pollutants Not emitted directly in air
Photochemical reactions
Nitrogen oxides absorb solar radiation
Produces irritating, toxic volatile organic compounds
Known as photochemical smog

12. Pressure changes in atmosphere
The higher you go the
less air there is to push
down on you

13. Temperature changes in atmosphere
What does this picture show us about temperature changes?

14. Layers of the atmosphere
1. Troposphere
Tropopause
2. Stratosphere
Stratopause
3. Mesosphere
Mesopause
4. Thermosphere

15. Layers of the atmosphere
1. Troposphere
Temperature decreases with altitude
All weather occurs here
Made of 99% nitrogen, oxygen, argon and carbon dioxide
Most dense at surface of Earth
Decreases with altitude

16. Layers of the atmosphere
2. Stratosphere
Temperature is constant up to 20km then increases (ozone layer)
No wind so air is calm
19% Atmospheric gases – the rest is ozone
Density is very thin

17. Layers of the atmosphere
3. Mesosphere
Temperature decreases with height
Nitrogen and Oxygen levels are the same as troposphere
There is very little movement but still dense enough to stop meteors

18. Layers of the atmosphere
4. Thermosphere
Temperatures increase because solar radiation is being absorbed
Very thin
Molecules can travel for miles before hitting one another
We can’t really describe its chemical composition because there are hardly any molecules here

19. Layers of the atmosphere

20. Earth-sun relationships
All energy for Earth’s weather and climate comes from sun
Earth absorbs less than one two-billionth of energy given off by sun
Still several hundred thousand times more than we need
Sun doesn’t heat everywhere on Earth evenly
Unequal heating causes wind and ocean currents

21. Earth’s motions Rotation Spinning on axis Happens every 24 hours
Revolution
Orbit around sun
Happens every year
Earth travels 113,000km/hr

22. Earth’s orientation
Why is it colder in the winter and warmer in the summer?
Seasonal changes happen
because of the tilt of the
Earth’s axis
Earth is tilted at from
perpendicular
Axis always pointed
toward North Star

23. Sun’s apparent path Varies with latitude and season
Angle of noon sun can vary up to 47 degrees in our location
In June when we are pointed toward the sun the rays hit us at a 73.5 degree angle
In December when we are pointed away it hits at a 26.5 degree angle

24. The Seasons and length of day

25. Section one review Compare and contrast weather and climate.
Why do seasonal changes occur?
How much of the Earth’s atmosphere is located below 5.6 kilometers?
How do ozone molecules form?
In which layers of the atmosphere does temperature increase with increasing height?
Explain what would happen to air temperatures in the troposphere if carbon dioxide were removed from air.

26. Heating the atmosphere
Heat and temperature are two different things
Heat is the energy transferred from one object to another because of a difference in their temperatures
Temperature is a measure of the average kinetic energy of the atoms or molecules of a substance
If energy is added to molecules they move faster and the temperature increases

27. Ways to transfer energy
1. Conduction
Transfer of heat through matter by molecular activity
Molecules are close to one another and when one gets excited it hits the one next to it which also gets excited
Like a metal spoon in a hot pot
Air is really poor conductor

28. Ways to transfer energy
2. Convection
Transfer of heat by mass movement or circulation within a substance
Like a lava lamp or hot air balloon
Sun warms objects, air around those objects gets heated by conduction then warm air rises

29. Ways to transfer energy
3. Radiation
Travels through vacuum of space
All objects, no matter what their temperature, emit radiant energy
Hotter objects radiate more total energy than colder objects
The hottest radiating bodies produce the shortest wavelengths
Objects that are good absorbers of radiation are good emitters too
Atmosphere doesn’t absorb all wavelengths-some get through

30. Ways to transfer energy

31. Electromagnetic waves
These waves move at 300,000km/second through space
Our atmosphere doesn’t slow them down too much
Waves move out from source like a pebble hitting water

32. Electromagnetic waves rainbow is always in same order as electromagnetic spectrum double rainbow is reversed

33. What happens to radiation?
1. Absorbed
Energy added and temperature increases
2. Transmitted
Energy passes through
3. Reflected
Energy bounces off object

34. What happens to radiation?

35. Reflection and scattering
Wave bounces off
object with same intensity
that it hit object
Scattering
Wave split into large
number of weaker waves

36. So why is the sky blue?
The air is full of small dust and gas particles
Light gets scattered in all directions
This is how light reaches underneath a shade tree
Blue has a very short wavelength compared to other colors
It gets scattered the most
Sunrise and Sunset are red/orange because of the angle we see them
They have to pass through a lot of particles
Red and orange are long wavelengths and everything else gets scattered away

37. absorption Water vapor and carbon dioxide are good absorbers
When they absorb energy their temperature rises
Known as Greenhouse Effect
This is actually a good thing
We’d be really cold without it
Different from Global Warming
This increase is caused or influenced by human activities

38. photosynthesis Small amount of energy not absorbed and then reradiated
Chlorophyll in plants absorb this energy and use it to make their own type of energy
So the sun is the main source for all energy on Earth

39. Section 2 review How are heat and temperature related?
What are the three ways heat is transferred?
What three things happen when solar radiation strikes an object?
How are scattering and reflection different?
Dark objects tend to absorb more radiation than light-colored objects. Explain whether dark objects or light objects on Earth’s surface would be better radiators of heat.

40. Temperature controls
Any factor that causes temperature to vary from place to place and time to time
Latitude
Differential heating of land and water
Altitude
Geographic position
Cloud cover
Ocean currents

41. Land and water Lands heats more rapidly but also cools
off more rapidly
Cities near water
have less
temperature
variations

42. Land and water Northern hemisphere 61% land 39% water
Southern hemisphere
19% land
81% water

43. Geographic position Windward coast Wind blows from ocean onto shore
Leeward coast
land out to ocean

44. Geographic position Mountains can get in the way Reduces effect
of windward location

45. altitude
Guayaquil
12m above
sea level
Quito
2800 m above

46. Cloud cover and albedo Albedo
Fraction of total radiation reflected by any surface
Clouds have high albedo
So does snow
During the day you want clouds to reflect sun away and keep you cool
At night you want clouds to reflect Earth’s heat back upon itself to keep you warm

47. Cloud cover and albedo

48. World distribution of temperature
Isotherms
Connect points of equal temperature
Look at World Isotherm Map on page 493
What effect does latitude have on temperature?
What effect does the distribution of land and water have on temperature?
Estimate the latitude range for temperatures between 20 and 25 degrees Celsius in the Northern Hemisphere.
Do you expect the color of the temperature band to change near the equator for the month of January? Explain your prediction.

49. Section 3 review What is a temperature control?
How do the heating of land and water differ?
Why is it cooler on a cloudy day? What happens to the radiation from the sun on these days?
Why do some coastal cities experience a moderation of temperature from water, while others do not?