air earth’s atmosphere. atmospheric pressure * the weight of the air above you. the more air that...
TRANSCRIPT
Atmospheric Pressure * The weight of the air above you. The more air that is above you the more pressure you will feel.
* Sinking air pushes down more- cold air is usually high pressure.
* Rising air pushes down less- hot air is usually low pressure.
So …. Atmospheric pressure is greatest near Earth’s surface
Decreases as you move out to space
Can vary from locations at the same level due to the density of the air
Cold Air vs. Warm Air Cold air is denser than warm air so has a higher pressure
Warm is less dense so has a low pressure
These masses of warm/cold air used to predict weather
Movement of AirWind
The movement of air molecules from an area of high pressure to an area of low pressure
Temperature differences on Earth’s surface create areas of different pressure and the winds that circulate our planet
Causes of temperature difference Earth is curved rather than flat so
more solar radiation is received at the equator
Air above equator is heated more than any place on Earth … heated air rises (low pressure)
Air above poles receives less radiation so air is cooler … colder air sinks (high pressure)
The Coriolis Effect Due to Earth’s rotation
Causes air masses moving south in Northern Hemisphere to be turned westward from their original paths
These wind patterns determine the weather and also when ships/planes can travel
Review ….. What 2 things determine our wind patterns on Earth ?
Differences in heating Coriolis effect
Jet Streams Located near top of troposphere
Flow west to east
2 jet streams in each hemisphere
Resemble fast moving rivers
Average speed between 97-185 km/h
Their positions in altitude and latitude from day to day / season to season
Local Wind Systems Land Breezes
Movement of air towards water
Sea Breezes Movement of air towards land