Greenhouse effect and climate sensitivity Flashcards
Why is the sun unusual?
Sun has an incredibly high temperature (~6000oC), sending out intense radiation in the small wavelengths.
The earth (recieving sunlight) has a much lower surface temperature than the sun, but nevertheless…
It has a temperature and the Earth itself emits radiation, at a level coordinating with it’s temperature (~15oC)
If everything is in equilibrium (no change in heat from the sun, no change in distances)
The earth and the moon will reradiate an equivalent amount of radiation to maintain a constant temperature.
The earth is interestingly warmer than the moon, relationship between radiational heat and gases…
What gases do and don’t take up heat?
O2 and N2 by and large don’t take up heat but CO2 and H2O do.
Flexible vs non flexible bonds
Flexible can change the orientation of the atoms that make up the molecule
In doing so temporarily absorbing extra energy which is then remitted
Absorption capacity of atmosphere depends on:
Amount of each type of molecule present
Absorption spectrum of each type of molecule
Why are generalisations of absorption often inaccurate?
To assume everything is absorbed and reemitted is wrong- there are clear window where no absorption occurs.
Where is energy exchange usually measured?
The GHGs lose heat at the top of the troposhere.
What is lapse rate?
The rate at which air temperature falls with increasing altitude.
Currently on Earth the more molecules of GHG added…
The more interception and re-radiation.
Adding GHGs is an ongoing process there is currently a disequilibrium.
Heat loss from the upper troposphere is not keeping up with heat gain via increased GHGs.
