1. The Atmosphere
Basic Structure

2. Composition Combination of many gases Hydrogen, Oxone, Xenon
Nitrogen - 78%
Oxygen – 21%
Water Vapor – 0% to 4%
Argon – 0.93%
Carbon Dioxide – 0.03%
Neon, Helium, Methane, Krypton, – 0.01%
Hydrogen, Oxone, Xenon

3. Key Atmospheric Gases Amount of nitrogen and oxygen are critical
Any significant change would end life on Earth
Water vapor
Helps with energy regulation
Exists as solid, liquid and gas
Carbon dioxide
Ozone
Ultraviolet (UV) radiation shield

4. Atmospheric Structure
Lower Atmospheric Layers
Troposphere
Closest to Earth’s surface
Holds most of the atmosphere’s mass
Most weather occurs here
Gets colder as you get higher
From 9km (poles) to 16km (tropics) high
Stratosphere
Mostly made of ozone (O3)
Gets warmer as you get higher
Top of layer is about 50km above the Earth’s surface

5. Atmospheric Structure
Upper Atmospheric Layers
Mesosphere
Gets colder as you get higher
Top of the layer is around 100km above Earth’s surface
Thermosphere
Holds a small part of the atmosphere’s mass
Gets warmer as you go higher (can exceed 1000oC)
Top layer is around 500km above Earth’s surface
Ionosphere – contains electrically charged particles
Exosphere
Outer most layer of Earth’s atmosphere
Contains light gases Hydrogen (H) & Helium (He)

6. Solar Fundamentals
The sun is the source of all energy in the atmosphere
Sun’s energy is transferred in 3 ways:
Radiation – through visible light, ultraviolet (UV) radiation & other forms of electromagnetic waves
Conduction – passed from one molecule to the next; must be touching
Convection – flow of a heated substance

7. Diagrams Structure of the Atmosphere Solar Radiation
pg. 273
Solar Radiation
pg.275
Energy in Earth’s Atmosphere
pg. 276

8. State of the Atmosphere
Temperature and Pressure

9. Temperature or Heat Temperature Heat
How fast or slow molecules move around
More molecules = higher temperature
Faster moving molecules = higher temperature
Heat
Transfer of energy between substances
Flows from warmer to cooler
Fuels atmospheric processes

10. Measuring Temperature
Fahrenheit (oF)
Water boils at 212oF Water freezes at 32oF
Absolute Zero at -523oF
Celsius (oC)
Water boils at 100oC Water freezes at 0oC
Absolute Zero at -273oC
Kelvin (K)
Water boils at 373 K Water freezes at 273 K
Absolute Zero at 0K

11. Atmospheric Temperature Changes
Dew Point
Temperature that air must cool to at constant pressure to reach saturation
Saturation is when air is holding as much water as possible
Air must be saturated for condensation to occur
Lifted Condensation Level (LCL)
Height at which air has cooled enough for condensation to occur
Point at which clouds form

12. Air Pressure and Density
Air is denser and has higher pressure closer to the Earth’s surface
Temperature – Pressure – Density Relationship
T P
T P Temperature Inversion -
a pocket of warmer air in
between cooler air
T D

13. Wind Cool air sinks because it is more dense
Forces warm, less dense air upwards
Wind moves from areas of high pressure to areas of low pressure
High and low pressure areas form due to uneven heating of Earth’s surface

14. Relative Humidity
Amount of water vapor in a volume of air relative to how much water vapor the volume of air can hold
Warm air can hold more water vapor
Expressed as a percent

15. Moisture in the Atmosphere
Clouds

16. Cloud Formation
Warm, less-dense air rises, expands and cools in a convection current
As the air reaches its dew point, water vapor condenses around condensation nuclei (sea salt, dust)
Can also form from orographic lifting
Wind encounters a mountain and is forced up
Collision of air masses of different temperatures

17. Stability and Latent Heat
Stability – when an air mass resists rising
Can become unstable if the air is cooler than the surface beneath it
Latent heat – energy stored in water vapor
Released as water vapor condenses
Warms the atmosphere
This can give energy to a storm and make it more intense

18. Types of Clouds Cirro –above 6000m Cirrus – wispy, stringy
HEIGHT SHAPE
Cirro –above 6000m Cirrus – wispy, stringy
Cummulus – puffy,
Alto – m lumpy looking
Stratus - featureless
Strato – below 2000m sheets
Nimbus – low, grey
Fog – on the ground rain clouds

19. Low Clouds Form from intense heating
Summer sun shining on dark fields
Air expands and rises, then begins to cool
At LCL condensation occurs and a cloud forms
If the cloud stay warmer than the surrounding air it will continue to grow
If not it will flatten and be spread out by wind
stratocumulus, layered cumulus, stratus

20. Middle Clouds Altocumulus, altostratus
Can be a mix of liquid water and ice crystals
Usually layered

21. High Clouds Cirrus, cirrostratus Made of ice crystals
Indistinct, continuous layer that sometimes covers the sky

22. Vertical Development Clouds
A cumulus cloud that starts as a low cloud and continues to grow through the middle heights and beyond
Becomes a huge cumulonimbus cloud with an anvil shaped top
Produce thunderstorms with torrential rains and high winds

23. Precipitation
Coalescence – when water droplets collide and make a bigger droplet
Primary force in warm clouds
Four main types are rain, sleet, snow, hail