Lecture 4: Atmosphere

Question 1

What does the atmosphere consist of?

Answer 1

It consists mainly out of nitrogen (78%) and oxygen (O2 - 21%). But also O3 and CH4 for a small part.

Gases have a long residence time in the atmopshere, resulting in a constant mixing ratio. If there is a high concnetration, there is more rapid mass transport in air and water.

Question 2

How do windflows function?

Answer 2

Air circulation emerges due to atmospheric pressure differences. Air pressure results from density, specific gas constant and temperature. Pressure differences between high and low pressure zones determine the main wind patterns.

Question 3

How does the previous knowledge relate/connect to the distribution of noise, radiation and pollution through the physical environment?

Answer 3

Vertical gradient in temperature: ‘lapse rate’ regulates mixing of air pollution and noise propagation. This causes pollution.

Matter, sound, and radiation can distribute via the different compartments of
the physical environment
 Deep surface lithosphere
 Soil including plants and animals biosphere
 Water ( hydrosphere
 Air ( atmosphere

Matter is distributed mainly via atmospheric movement: wind. For sound this is considerably less and for radiation this is almost 0.

Question 4

How does the temperature increase once we go past 12-14 km in the air?

Answer 4

The ozone layer. This absorbs most of the harmful UV-radiation of the sun. Ozone is harmful at groundlevel as it’s highly oxidative.

Question 5

How are energy and temperature related?

Answer 5

Energy (in unit joule) and temperature (in units Kelvin, Celsius, or Fahrenheit, etc ..) are related physical quantities. –> energy imbalances are the driving force behind temperature differences

Question 6

What is the atmospheric balance influenced by?

Answer 6

Absorption, scattering, reflection: influenced by zentih angle, cloud cover, aerosoles.

Question 7

How does solar radiation warm up the earth?

Answer 7

surface radiation
thermals (convective transport of heat, conduction)
evaporation (latent heat because of condensation).

Question 8

Explain how the energy balance in the troposphere works.

Answer 8

vertical gradient in temperature: ‘lapse rate’. Mixing of air pollution and propagation of noise.

Air pressure decrease with height (weight of overlying air decreases –> air expands). Expansion implies pressing surrounding air away –> expansion costs energy. Loss of energy causes parcel to cool

Question 9

Explain Adiabatic means, Differentiation means and a derivative

Answer 9

Adiabatic means: exchange of energy with the environment can be neglected

Differentation means: action of computing a derivative (afgeleide bepalen -mathematics)

Derivative is: an anti-integral (afgeleide -maths).

Question 10

Explain circulation of air

Answer 10

circulation equals movement. In order to move, you need force. Force / surface = pressure. Air circulation emerges due to atmopsheric pressure differences.

Question 11

Where does air pressure result from?

Answer 11

Pressure = density: air, water, aerosols * specific gas constant: water vapour * temperature: mostly dominant

Question 12

Explain how weather works due to the three phases

Answer 12

1. vertical movement caused by temperature differences
2. in the sky, air flows from high to low pressure
3. the flow of air in the sky results in pressure differences and a flow in opposite direction close to the earth surface.

Question 13

Where does air pressure most dominantly result from?

Answer 13

Temperature

Question 14

How does temperature relate to air pressure?

Answer 14

(Differences in) heating –> air temp. –> air pressure –> movement

Summer: low pressure zones above land/continent

winter: low pressure zones mainly located above relatively warmer open water (oceans, lakes, sea)

Question 15

Pressure differences between high and low… determine the main …

Answer 15

pressure zones, wind patterns

Question 16

›−Γ>0,01ΤΤ℃m means … atmosphere, … vertical motion
›
›−Γ<0,01ΤΤ℃m means … atmosphere, … vertical motion
›
›−Γ=0,01ΤΤ℃m means … atmosphere, … vertical motion

Answer 16

1. unstable, intense
2. stable, restricted
3. neutral, standard

Question 17

What is the lapse rate?

Answer 17

Vertical gradient in temperature. It regulates mixing of air pollution and propagation of noise. the dry adiabatic lapse rate = -.9,77 c/km

Question 18

What happens when the atmosphere is unstable?

Answer 18

The earth surface gets heated, including the air layer on top of it. Atmosphere is unstable –> air parcels will expand, resulting in a force upwards. Since there are vertical air movements there are thus also horizontal air movements.

Question 19

How does cloud cover influence the (un)stability of the atmosphere?

Answer 19

Clouds with water drops/ice crystals. Supply of heat is caused by condensation (release of latent heat). Clouds reflect sun light –> influence on energy balance (radiation). More energy in atmosphere, less on the earth surface.

Question 20

Wind is caused by vertical … and horizontal …

Answer 20

Vertical differences in density of the air emerging from temperature differences caused by solar radiation (in/heating) and surface radiation (out/cooling).

Horizontal pressure differences, emperature differences at the earth surface –> heated air, ascending (hot air balloon rides)

Question 21

What is inversion?

Answer 21

It blocks the vertical mixing of air, and can therefore increase or decrease hindranceo f air and noise pollution. Warm air above cold air.