Net radiation, radiative forcing and Earth's sensitivity Flashcards
The energy balance can be described via net radiation
This is…
the balance between the incoming and outgoing radiation for the planet- measured at the tropopause.
What can cause a temperature change?
A perturbation (such as a change in GHG concentration) can drive a change in net radiation, temporarily disturbing the balance
What is radiative forcing?
A change in net radiation driving a temperature change- not necessarily a change in radiation—e.g., incoming solar—but a change that affects net radiation.
What happens in negative radiative forcing?
- Less solar energy in (e.g change in solar constant )
- Overall reduction of energy in system
- Over time, temperature decreases
- Over time, emissions decrease to reach new balance
What happens in positive radiative forcing?
- No change in radiation in but a temporary decrease in radiation out (more absorbing in troposphere)
- Temperature increases over time as a result
over time - Earth’s IR emissions adjust to restore balance
What is climatic sensitivity?
The response of the Earth system to the overall radiative forcing.
What comes in (solar) =
what goes out (IR emissions)
If no change to incoming radiation or to atmosphere, Earth’s temperature is (on average)…
constant and warmer than it would be with no GHG-containing atmosphere.
If incoming radiation changes, there is a…
temporary disequilibrium.
The earth warms or cools, and outgoing radiation adjusts to regain equilibrium.
If atmospheric composition changes, outgoing radiation
progresses differently through the troposphere, also causing a…
temporary disequilibrium and also causing temperature to change.
Subsequently outgoing radiation adjusts to restore equilibrium.
This does not happen instantaneously.
