L4 - Climate forcing and response

Question 1

Instantaneous forcing

Answer 1

only consider extra LW radiation from stratosphere to troposphere

Question 2

Adjusted radiative forcing

Answer 2

stratosphere emits more radiation - it will cool. Extra LW radiation becomes lower

Question 3

What is an aerosol?

Answer 3

Solid or liquid particles suspended in air with diameters larger than 0.1 um and smaller than 100um. Also called particulate matter, and particles are often hygroscopic. Water/ice film is substrate for chemical reactions

Question 4

Hygroscopic

Answer 4

Ability of a substance to attract and hold water molecules from the surrounding environment

Question 5

Natural aerosol examples?

Answer 5

Sea salt, desert sand (swept by storms), wind erosion, whirlwinds, volcano emissions (gases, ash) and biogenic VOC

Question 6

What are the slowest growing aerosols?

Answer 6

Fine aerosols only grow slowly as accumulation is between 0.01-0.1 um.

Question 7

What are the slowest moving aerosols?

Answer 7

Large; this means less collisions. These aerosols have already vacuum cleaned their environments

Question 8

How are aerosols removed by the environment?

Answer 8

By scavenging by clouds/rain droplets and rainout. Removal of coarse aerosols also by sedimentation

Question 9

What is a direct effect of aerosols?

Answer 9

Scattering and absorption of radiation

Question 10

What is an indirect effect of aerosols?

Answer 10

Can cause clouds to have a higher albedo effect. This is because there is a larger amount of small droplets compared to cleaner conditions

Question 11

Radiative dampening

Answer 11

The increase of IR emissions into space for a given increase in temperature

Question 12

When temperature increases will all other fluxes stay the same?

Answer 12

No, radiation fluxes will not stay the same.
- Emissivity of the atmosphere will change
- T difference S-A will change
- Albedo will change

Question 13

Is there a direct impact of radiative forcing on albedo?

Answer 13

No, but subsequent changes in temperature can change albedo and thus amount of radiation absorbed

Question 14

The temperature of the atmosphere and surface adjust balance between?

Answer 14

Absorption solar energy and IR emission to space

Question 15

What happens when Ta increases?

Answer 15

Water vapour increases as atmosphere holds more water, Ea goes up and IR to space decreases

Question 16

when x is larger in DX/DT is it a positive or negative feedback?

Answer 16

positive