TOA vs Top of model

[kruss@wisc_edu]

Hi.  What is the difference between top-of-atmosphere (TOA) and top-of-model (T) in CCSM3 (and probably more recent models)?  For example, there is a choice for net solar flux (FSN) that is FSNTOA or FSNT.  On the other hand, there is no similar choice for upwelling longwave flux... it just offers the top-of-model version, FLUT.Thanks in advance...

 

[hannay]

The top of the model in CAM is 3.64mb so it is not the top opf the atmosphere. 

WACCM has a higher top

 

[alcide_zhao@ed_ac_uk]

Hi Kare,I wonder if you have found the right diagnostics for longwave radiations at TOA?Cheers, Alcide 

 

[kruss@wisc_edu]

Hi Alcide,I went with the top-of-the model (TOM) variables, because the TOM had all the variables that I needed.  Since the top of the model is very close to the top of the stratosphere, this should be OK for my purposes.  Also, the "Description of the NCAR Community Atmosphere Model (CAM 3.0) ", 2004, states on p. 113 that "…solar fluxes are calculated… for the top of model (TOM) at layer 1 and the top of atmosphere (TOA)  corresponding to layer 0.  The TOM fluxes are used to compute the model energetic balance, and the TOA fluxes are output for diagnostic comparison against satellite measurements."

 

[alcide_zhao@ed_ac_uk]

Hi Kare,Thanks a lot for getting back to me. Your comments help a lot. I believe it is alos useful for other users!Cheers, Alcide