Atmospheric Conditions Flashcards
Approx 50% of SR reaching the surface is absorbed and re-emitted as IR radiation. The energy is therefore
Effectively recycled from the surface to the atmosphere, then back to the surface, therefore being trapped, thus raising the temperature.
The atmosphere traps energy at the surface,
About 20% of SR and 90% of IR is absorbed by the atmosphere.
In a steady state, the
Inflow and outflow are equal for a specific quantity, the amount of that quantity remains constant.
The dry adiabatic lapse rate, DALR, is
9.8 ‘C km ^-1
The saturated adiabatic lapse rate, SALR, depends on
The amount of water vapour present.
When dry air in the atmosphere has a larger ELR than DALR,
It is unstable.
A slight change, caused by moving or heating air, leads
To a continued motion.
If heating / movement leads to suppression of motion,
It is stable.
For convection to occur:
There must be a downwards motion of air to accompany the rising of warm air.
As a parcel of air rises in an unstable situation, it’s
Temperature drops, but by a smaller amount than that of the air surrounding it.
Negative feedback is a change in
The relative amounts of incoming and outgoing energy, which returns Earths atmosphere to a new steady state.
Positive feedback is when a change in the system
Doesn’t help the system to return to a steady state, instead it pushes it further away from a steady state.
