The structure of the atmosphere

Question 1

What are the 4 layers of the atmosphere

Answer 1

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

Question 2

What is the atmosphere?

Answer 2

A mixture of gases held to Earth by gravity, and consists of 78% nitrogen, 20.95% oxygen and other gases.

Question 3

Do temperatures increase or decrease with height in the troposphere?

Answer 3

Decrease, averaging 6.5°C per km.

Question 4

In which layer do most weather processes occur?

Answer 4

The troposphere, as they operate within 16-17km of the earths surface.

Question 5

What is the height of the troposphere at the poles?

Answer 5

8km

Question 6

What is the height of the troposphere at the tropics?

Answer 6

17km

Question 7

How far does the stratosphere extend to?

Answer 7

Up to 50km above the surface

Question 8

Do temperatures increase or decrease with height in the stratosphere?

Answer 8

Increase

Question 9

Which layer of the atmosphere is cloud and dust free?

Answer 9

The stratosphere

Question 10

What does the ozone layer in the stratosphere absorb and filter?

Answer 10

Ultraviolet radiation

Question 11

What do the differences in temperatures over polar and tropical latitudes lead to?

Answer 11

Strong horizontal air movements at great heights.

Question 12

To temperatures increase or decrease in the mesosphere?

Answer 12

Decrease with altitude

Question 13

Do temperatures increase or decrease in the thermosphere?

Answer 13

Increase, at a constant rate up to as much as 1500°C

Question 14

What does the atmospheric heat budget of the Earth depend on?

Answer 14

The balance between incoming solar radiation and outgoing radiation from the planet.

Question 15

Why has the energy budget remained constant over the last few thousand years?

Answer 15

Due to incoming and outgoing energies being equal

Question 16

What are the six components to the daytime energy budget?

Answer 16

• Incoming shortwave radiation
• Reflected solar radiation
• Surface absorption
• Sensible heat transfer
• Long-wave radiation
• Latent heat (evaporation and condensation)

Question 17

What are the four components that the night time energy budget consists of?

Answer 17

• Long wave radiation
• Latent heat transfer
• Absorbed energy returned to earth (subsurface supply)
• Sensible heat transfer

Question 18

What 3 things is incoming solar radiation affected by?

Answer 18

• Latitude
• Season
• Cloud cover

Question 19

What is albedo?

Answer 19

The proportion of energy that is reflected back to the atmosphere.

Question 20

What surface has the highest albedo?

Answer 20

Fresh snow has 75-90% albedo

Question 21

What is environmental lapse rate (ELR)?

Answer 21

The decrease in temperature usually expected with an increase in height through the troposphere

Question 22

Why doesn’t it get hotter as you move towards the sun?

Answer 22

As the troposphere is primarily heated from the bottom, because the surface is much better at absorbing solar radiation than the air.
The energy from the warm surface warms the air above the ground through conduction
This warm air rises through the troposphere through convection.

Question 23

Does atmospheric pressure increase or decrease as you move up through the atmosphere?

Answer 23

Decreases

Question 24

What occurs when a small parcel of air is heated at the surface?

Answer 24

The small parcel will begin to rise as it is warmer than the surrounding air. This parcel will get colder as it rises and then expand.

Question 25

Why does air cool as it rises?

Answer 25

When air expands, there are less interactions between molecules, therefore temperature falls

Question 26

What is adiabatic expansion?

Answer 26

The description of what happens to a parcel of air as it rises as air pressure decreases, causing an increase in volume and decrease in temperature.

Question 27

What determines how fast air cools?

Answer 27

How saturated the air is

Question 28

What is dry adiabatic lapse rate?

Answer 28

The rate at which a dry parcel of air (less than 100% humidity = no condensation) cools.

Question 29

What is saturated adiabatic lapse rate?

Answer 29

The rate at which a saturated parcel of air (condensation is occurring) cools.

Question 30

Why does saturated air not cool as quickly?

Answer 30

As it contains condensed water. When condensation occurs latent heat is released (opposite of evaporation) preventing it from cooling as quickly.

Question 31

How do clouds form?

Answer 31

• Clouds form when rising air has cooled to its dew point.
• Once condensation begins, latent heat is produced and air cools more slowly as it rises (SALR)
• Once the parcel of air reaches a temperature the same as that surrounding it, it will stop rising.
  Creating a cloud

Question 32

How do cirrus clouds form?

Answer 32

When warm, dry air rises - causing water vapour deposition onto rocky or metallic dust particles at high altitudes

Question 33

Where are cirrus clouds found?

Answer 33

At higher altitudes

Question 34

What does a cirrus cloud look like?

Answer 34

Appear delicate and wispy with white strands

Question 35

What does a cumulus cloud look like?

Answer 35

A cloud with a flat base, and are described as fluffy

Question 36

How are cumulus clouds formed?

Answer 36

They develop due to convection

Question 38

What does a stratus cloud look like?

Answer 38

Low level clouds, that look like they’re layered with a uniform base

Question 39

How are stratus clouds formed?

Answer 39

When gentle breezes raise cool, moist air over colder land or ocean surfaces