M3L1 - Energy & Feedback Loops

Question 1

Emissivity

Answer 1

The proportion of energy received to emitted

Question 2

Black body

Answer 2

Something that emits 100% of energy it absorbs (emissivity = 1)

Question 3

Planck’s law

Answer 3

For a given object, the energy at any specific wavelength is dependent on temperature (measured in kelvin)

Question 4

Stefan-Boltzmann Law

Answer 4

There is a direct relationship between an object’s temperature and how much radiation it emits

Question 5

What does EMR scattering in the atmosphere depend on

Answer 5

• Wavelength of the EMR compared to particle size
• Amount of particles/gasses
• How far the EMR travels through the atmosphere

Question 6

Three types of scatter

Answer 6

• Rayleigh scattering
• Mie scattering
• Nonselective (geometric scattering)

Question 7

Rayleigh scattering

Answer 7

• Shorter wavelengths of visible spectrum are scattered by particles smaller than the wavelengths of light (including dust, NO2 and O2)
• Explains why sky is blue

Question 8

Mie scattering

Answer 8

• Occurs when the wavelength of EMR is similar to the particles in the atmosphere (or particles are larger)
• Driven by presence of aerosols

Question 9

Aerosols

Answer 9

Mixture of gasses, dust, water vapour

Question 10

Nonselective (geometric scattering)

Answer 10

• Scattering by particles much larger than the wavelength
• Water vapour and clouds
• Why clouds are white (scatter all wavelengths equally)

Question 11

Why do contributions to greenhouse effect vary

Answer 11

Based on characteristics of the gas, how much there is, and what indirect effects it has

Question 12

Water vapour

Answer 12

• High relative contribution to greenhouse effect
• Humans not influencing the amount directly
• Residence time is short (~9 days)

Question 13

New and emerging compounds

Answer 13

• Sulphur hexafluoride is a growing concern
• 23,500 more potent than CO2
• Used in high voltage electrical applications
• Often unaware of implications of new compounds until they have been around for a while

Question 14

Carbon sources and sinks

Answer 14

• Most things are in balance
• Known out of balance (burning fossil fuels faster than they are forming)
• Unknowns (permafrost flux, methane hydrate amount)

Question 15

What is global warming potential standardised to

Answer 15

CO2

Question 16

Methane hydrate

Answer 16

Formed when water and methane gas come together at
high pressures and low temperatures in oceans

Question 17

Ocean acidification

Answer 17

• Oceans absorb ~1/3 of co2 released in atmosphere
• Increases concentration of hydrogen ions, decreasing pH
• Carbonic acid acid formation and subsequently dissociates releasing hydrogen ions (H+) and bicarb (HCO3-)

Question 18

Radiative forcing

Answer 18

• Measure of influence a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system
• Internal forcings: atmospheric, surface
• External (solar forcing)

Question 19

Feedback loops

Answer 19

• Positive adds to initial change
• Negative reduces initial change

Question 20

Environmental stability

Answer 20

• Stable: Deviations up to a certain point from equilibrium end up returning to equilibrium, or new
  equilibrium
• Unstable: Small perturbations result in larger shifts and a lack of ability to return to equilibrium

Question 21

Resiliency

Answer 21

• Ability for a system to keep functioning after being subjected to disturbance
• Not always a positive
• Examples: Soil resilience in agriculture; overfishing; deforestation; electrical grids