1. Earth's Atmosphere Troposphere Stratosphere
Four distinct layers
thermal characteristics, chemical composition, movement, and density
Troposphere
starts at the Earth's surface and extends 8 to 14.5 kilometers
the most dense
higher in this layer, temperature drops from about 17 to -52C
almost all weather is in this region
Stratosphere
extends to 50 kilometers (31 miles) high
dry and less dense
temperature in this region increases gradually to -3C
Contains the ozone layer

2. extends to 600 kilometers (372 miles) high
Mesosphere
extends to 85 kilometers (53 miles) high
temperatures again fall as low as -93C
chemicals are in an excited state, as they absorb energy
Thermosphere
extends to 600 kilometers (372 miles) high
temperatures in this region can go to 1,727C
Exosphere
starts at the top of the thermosphere and continues until it
merges with interplanetary gases, or space
Mostly Hydrogen and Helium at extremely low densities

4. Temperature Profile of the Earth's Atmosphere
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5. Composition of the Atmosphere
Nitrogen (N2, 78%) Oxygen (O2, 21%) Argon (Ar, 1%)
other stuff:
water (H2O, 0 - 7%)
"greenhouse” gases or Ozone (O, %)
Carbon Dioxide (CO2, %)

6. How’s the WEATHER???
Weather vs Climate
Weather - conditions in the TROPOSPHERE
at a particular time and place
Climate - weather patterns that are typical for a larger region
over a longer period of time
What factors affect the weather???
heat from the sun
atmospheric pressure
moisture in the air (humidity)

7. Some like it HOT!!! RADIATION - energy from the sun
transfer of energy by electromagnetic waves
20% absorbed by clouds and atmosphere
50% absorbed by surface
5% reflected by the surface
25% reflected by clouds and atmosphere
CONDUCTION - transfer of energy from fast-moving molecules to slow-moving
air is heated by the radiant energy absorbed by the surface
CONVECTION - transfer of heat due to different densities
Step heated air becomes less dense
Step 2 rises through the cooler heavier air above it
Step 3 cooler air SINKS toward the surface
then repeat steps
CONVECTION CURRENT

8. You think you’re under pressure???
atmospheric pressure
force exerted by the weight of the air
High pressure
Low pressure

9. High pressure vs low pressure
Too much pressure???
High pressure vs low pressure
High- cool air is dense so it sinks Low - warm air is less dense soooo?
Between these pressures wind is created...
what determines the strength of the wind?
Wind - movement of air from one place to another
****all winds are caused by temperature and pressure differences
uneven heating of earth’s surfaces!!

10. Breezy
Watch

11. The Hydrologic Cycle Evaporation water heated by the sun
surface molecules become energized
rise as invisible vapor into the atmosphere.
Transpiration Water vapor emitted from plant leaves
growing plant transpires 5 to 10 times as much
water as it can hold at once
Condensation Water vapor rises,cools and condenses on particles of dust
becomes liquid again or turns directly into a solid
(ice, hail or snow)
water particles collect and form clouds
Precipitation rain, snow and hail comes from clouds
Clouds move over the world, propelled by air currents
they cool becoming saturated with water
water begins to fall as rain, snow
or hail

13. How wet is your little brother??
Relative Humidity
water vapor actually in the air
the maximum it can hold at that temperature
x 100
How does HEAT affect humidity??
What is saturated air??
What is the dew point??
As it measures up......
psychrometer measures the amount of relative humidity in the air

14. How much water can air hold?
Dependent on temperature
Reported in density g/m3
The warmer the air…the more it can hold
30 C ?
30 g/m3

15. x 100 water vapor actually in the air
At 25 C the actual water vapor pressure is 10g/m3
What is the relative humidity?
water vapor actually in the air
the maximum it can hold at that temperature
x 100
RH = (10g/m3 / 20g/m3) X = 50%

16. Coriolis Effect
Once air has been set in motion by the pressure gradient force, it
undergoes a deflection from its path. This deflection is called the
"Coriolis force" and is a result of the earth's rotation.
pressure gradient results in a net force that is directed from high to low
pressure - pressure gradient force ???????
                       

17. Geostrophic Wind Results from pressure gradient and Coriolis force