Introduction #2 B The Earth’s Atmosphere

The thickness of our Atmosphere

Mt. Logan 5959 m ft Mt. Everest 8850 m ft

Another look at the make-up of our atmosphere.

Just an interesting slide for now - more on clouds later in the course.

When particles become charged in the Ionosphere we get the Aurora Borealis

Let’s briefly take about some of the simple characteristics of our Atmosphere: Temperature, Pressure and Wind.

The different Temperature scales

Remember the shape of the earth has something to do with Temperature and Location. Temperature Range is the Hottest - Coldest What do you notice?

In the Troposphere (where we live) it is normal for the temperature to decrease with altitude. This is called a normal lapse rate

04_30b.jpg In a temperature inversion - the temperature rises with altitude. This is called an inverted lapse rate

This is more typical - At first temp. decreases then you reach a section where the temp. increases with altitude. The air eventually reaches an altitude where it begins to cool again. Let’s say the ground is cool and then a warm air mass moves in above the ground - an inversion is created. See the next slide for a negative effect.

Inversions can be harmful The hot air from the stacks rises till it meets are with similar temperature - then it just flattens out.

What happens to our atmosphere when you add this to it?

Air Pollution Look at the pictures closely and you can see the areas with pollution and the areas without - good use of Remote Sensing.

The Urban Environment The pollution and dust created by a city can create a Greenhouse effect called the Urban Heat Island.

Urban Heat Island

A simple Barometer to measure Pressure

Air Pressure Readings

Pressure like Temperature decreases with altitude.

The relationship between Temperature and Pressure. As the thermometers next to the balloons indicate (a, b), rising air cools adiabatically due to expansion and (c, d) descending air warms adiabatically due to compression.

Warm at the bottom - Cold at the top!

How are atmosphere protects us!

The Ozone and it’s ability to block harmful ultra- violet rays has been in the news in the last few years.

The Ozone hole!

Finally and quickly - Wind is created when there is a difference between pressure. Air travels from a high pressure to a low pressure. But it is not that simple! The pressure gradient is the difference in pressure and determined the force of the wind.

How light winds and strong winds are created.

Wind Vane and Anemometer What does this measure?

Wind power!

Because the earth rotates the wind curves (coriolis effect). Much more on this later. The red arrows represent the air movement - but the air over a low pressure rises while the air over a high pressure descends.

Air Masses, which have specific Pressure and Temperature characteristics are what effects our climate. Wow, Temperature, pressure, wind - it’s all connected!

The End