L5 - Feedbacks Flashcards
Clear sky feedback (direct feedback)
Initial radiative forcing induces changes in?
- Water vapour in atmosphere
- Vertical distribution of water vapour
- Tropospheric lapse rate (in cloud free regions)
Emissivity
the ratio of radiation of an object to that of a blackbody at the same temperature
negative lapse rate feedback?
larger temp change in the upper troposphere
positive lapse rate feedback?
larger temperature change at the surface
Where is global warming strongest?
Warming is amplified at the poles (2-6 times stronger) due to snow albedo feedback and increase in lapse rate
What is the impact of doubling co2 on lapse rate at the equator?
This will result in a negative lapse rate feedback with a larger temp change in upper troposphere. This is because there is more water vapour in the atmosphere and higher up, increasing temps here. However at the equator there is some evaporative cooling due to more rainfall
What is the impact of doubling co2 on lapse rate at the poles?
A positive lapse rate feedback will result with a larger temperature change at the surface than in the upper troposphere. This is because increasing co2 increases ice melting thus lowers albedo and more absorption takes place at the surface, however there is little change higher up.
Temperature gradient (Teq - Tp):
Lower troposphere -> negative trend
Upper troposphere -> positive trend
Positive ice albedo
cooling amplified by LW radiation reflected
Negative ice albedo
melted ice emits more LW radiation, lapse rate increases, less water vapour in lower atmosphere as surface dries.
Cirrus clouds
high thin clouds with a LOW albedo. Tend to warm. Long wave term dominant
Cumulus clouds
low thick clouds with HIGH albedo. Tend to cool. Short wave albedo term dominant
Rubisco
primary carboxylase of the photosynthetic process.
- Binding to O2 = respiration
- Binding to CO2 = photosynthesis
Chloroplasts
specialized cell organelles which are located in mesophyll and palisade cells in leaves
Law of diminishing returns
when you increase the limiting factor (co2), the short term plant response will likely saturate
