Atmospheric Composition and structure

Question 1

How much of the Earth’s mass is contained in the atmosphere?

Answer 1

0.0001%

Question 2

What are the permanent gases?

Answer 2

• Nitrogen
• Oxygen
• Argon

Question 3

Nitrogen makes up how much of the atmospheric composition?

Answer 3

78%

Question 4

Oxygen makes up how much of the atmospheric composition?

Answer 4

21%

Question 5

Argon makes up how much of the atmospheric composition?

Answer 5

0.93%

Question 6

Nitrogen, oxygen, and argon make up how much of atmospheric composition?

Answer 6

99.93%

Question 7

Variable gases include:

Answer 7

Water vapour (0.25%) carbon dioxide (0.037%), ozone (0.01%), methane (1.7ppm)

Question 8

Aerosols:

Answer 8

small solid particles or liquid droplets in the air

Question 9

Aerosol sources and effects:

Answer 9

• wind generated dust
• volcanic eruptions
• sea spray
• combustion by-products

Question 10

Aerosol effects:

Answer 10

• reduce visibility
• health effects
• formation of cloud droplets
• RADIATIVE EFFECTS (Climate
  Change)

Question 11

Troposphere

Answer 11

• adjacent to surface
• vertical decrease in
  temperature (-0.6°/100m)
• generally well mixed
  (convection and friction)
• contains almost all of atmospheric water vapour
• all ‘weather phenomena’
  take place within this
  layer
• average barometric
  pressure at sea level:
  1013 hPa

Question 12

Tropopause

Answer 12

• top end of troposhere
• start of temp. inversion
• avg. barometric pressure: approx. 225 hPa (75%)
• avg. altitude dependent on
  latitude
• Poles: ~ 8km
• Equator: ~ 17km
• avg altitude dependent on
  season:
  Minimum: winter – spring
  Maximum: summer - fall

Question 13

Stratosphere

Answer 13

- bottom half: isothermal
top half: temp. inversion
\+0.25°/100m
- ozone layer (≤10ppm):
absorption of harmful UV radiation by O3
- geographic and spatial
variability of ozone
concentration and temp.
- water vapour content
extremely low
- very little cloud formation

Question 14

Stratopause

Answer 14

• top end of stratosphere
• end of temp. increase
• avg. altitude: approx. 50km
• avg. barometric pressure:
  ≤ 1hPa (99.9%)

Question 15

Mesosphere

Answer 15

• temp. decrease with
  height
  approx. 0.2-0.3°/100m
• vertical mixing possible

Question 16

Thermosphere

Answer 16

• 85 – 800km
• continuous temp. increase due to absorption
  of UV radiation
  (difference between
  temperature and heat)
• consists primarily of
  molecular and atomic
  oxygen and nitrogen

Question 17

Isobars

Answer 17

lines that connect all points with same pressure

Question 18

Wind moves from ___ pressure to ___ pressure

Answer 18

high to low

Question 19

what does wind speed depend on?

Answer 19

the pressure difference - greater the difference, the faster the wind

Question 20

wind rises in ____ pressure and sinks in area of _______

Answer 20

rise in low

sink in high

Question 21

a rise in low pressure creates…

Answer 21

clouds

Question 22

a sink in high pressure makes…

Answer 22

clear skies

Question 23

Ideal gas law:

Answer 23

describes relationship between pressure, density, and temperature

Question 24

Pressure ____ with increasing height. Why?

Answer 24

decreases because as altitude increases, the number of air molecules decrease.

Question 25

When depth decreases, pressure is _____.

Answer 25

Reduced because the deeper you go under sea, the greater the pressure of the water pushing down on you is