[RegCNET] idirect

[Fabien Solmon]

Hi Prodromos !

idirect=1 = aerosol without climatic feedback BUT radiative forcing 
calculated .
the radiative forcing is calculated on line , passing 2 times in the 
clear sky radiative transfer routine
idirect=2 allows the aerosl to feedback on the radiative tendencies ;
in this case the radiative forcing calculated  accounts implicitely for 
atmosphere feedback  ( so it is not a radiative forcing stricto sensu )
idirect = 0 : no radiative forcing is calculated so you save a bit of 
time if you just want to do transport of aerosols ; for example if a 
French nuclear power plant explodes , you are first more concerned by 
the transport than the climatic impact ..

the TOA radiative forcing is calculated  by the difference of top of 
atmosphere net clear sky SW flux ( which is equivqlent to mqke the 
difference between outgoing SW flux) between no and with aerosol .. same 
for the surface forcing ...


climate impact = idirect =2 - idirect=1 or idirect=0 ...

hope it helps

cheers

fabien