1. Variable Gases + Atmospheric Pressure and Structure (Video)

2. Another atmospheric gas with 2 roles is Water Vapor
Water vapor is invisible – don’t confuse it with cloud droplets
Atmospheric amounts vary between almost 0% in deserts to 4% in tropics
Typical values in our area are about 1-2%
Some satellites sensors can detect actual water vapor in atmosphere
Water Vapor Image
Visible Image 2

3. Aside from providing us with precipitation, H2O Vapor…..
….stores a ton of heat!

4. Another gas which stores a ton of heat is Carbon Dioxide (CO2)
Small percentage of total atmosphere
But, very important green house gas
Sick of hearing about CO2??
How many have seen the movie “An Inconvenient Truth” or read the book?
Mauna Loa Observatory 4

5. Aerosols are an important part of our atmosphere
Tiny, solid airborne particles
Aerosols can be man-made (smoke, ash) or naturally occurring (like sea salt or dust)
AKA Cloud Condensation Nuclei
Some aerosols are very beneficial and, in fact, are required for condensation to occur.
Video 1
Video 2 5

6. Atmospheric pressure is the weight of all the air molecules in a column of air above the surface
• So, Atmospheric pressure is simply the weight of the air.
As you ascend (go up), atmospheric pressure decreases
Why?

7. Because Air Density Decreases

8. Atmospheric pressure increases increases less decreases
If more air molecules are packed into a column, the density ___________ and the atmospheric pressure __________.
On the other hand, when there are fewer molecules in the column, the air weighs _______and the surface pressure __________.
increases
increases
less
decreases

9. Average sea-level pressure = 1013.25 mb or 29.92 in.
Most common units for atmospheric pressure are
millibar (mb) and inches of mercury
Average sea-level pressure = mb or in.
So, the numbers you see on Weather Maps should start meaning something to you right about now > 9

11. Air pressure is Measured using a barometer…. Video

12. The vertical structure of the earth’s atmosphere is complex
The atmosphere is composed of different layers

13. A View from Space. How deep is the atmosphere?

14. Draw this!

15. Troposphere- lowest level
All Weather occurs in this region
Temperature decreases with height
This is because sunlight warms the surface of the earth, which then warms the air above it.
The rate at which air temperature decreases with height is called the lapse rate.
Average lapse rate = 6.5°C/1000m = 3.6°F/1000 ft

16. Stratosphere Ozone Layer is located here Ozone Video
Temperature increases with height
Usually, the higher up you go, the cooler it gets
So, when it gets warmer as you ascend, we call it an inversion
This happens in the lower atmosphere (troposphere) too
In fact, the area of the world where it happens most is right here on the Central Coast of California
We will talk more about this later….

17. Mesosphere
The prefix, Meso = middle, so the mesosphere is the middle layer of the atmosphere
Temperature decreases with height

18. Video Thermosphere Contains the ionosphere, where Auroras occur
Temperatures increase with height
Video