Clear-Sky Aerosol Optical Depth

[phoenix2@illinois_edu]

I'm trying to find the CAM5 variable that correspond to clear-sky (clouds excluded) aerosol optical depth. There are a few variables which I think it could be but am not sure. There are AODVIS, AODMODE(1-7) and AODABS, but I'm not really sure what the differences are between these variables. Also, is there any documentation online that gives more detail to what the CAM variables are besides what is given on the CESM Master List?
Thanks,Dan

 

[tilmes]

Hi Dan,AODVIS is the atmospheric optical thickness due to ambient aerosol in the wavelength of the visible light. This wavelenghts is around 500nm.AODABS is the atmospheric absorption optical thickness due to abient aerosol in the wavelength of 550nm, I think. So this variable only includes the absorbing part of the optical thickness.AODMODE(1-7) I am not sure, so I hope others can help here,
Cheers, Simone 

 

[phoenix2@illinois_edu]

Hi Simone, Thank you, this was helpful! Dan

 

[thibaut_lurton@cnrs-orleans_fr]

Hello to all,

To follow up on this thread... I'm a bit confused about the optical depths output variables given by WACCM.

We are currently using an FSDWSF compset, which I believe induces a bulk aerosol model. As I understand it, this bulk mode leads to the output of an "AEROD_v" variable representing the total aerosol optical depth in the visible band (this variable would be called "AODVIS" with MAM).

I also found an output variable PURSULOD, which I reckon means "pure sulfate optical depth".

Now, when comparing the values of AEROD_v and PURSULOD, I would have expected to have a total aerosol optical depth greater than PURSULOD, since the latter is part of the former (I'm assuming it is also calculated in the visible band).
Surprisingly, it turns out that PURSULOD can give higher numbers... Also, its features seem more convincing (with respect to our scientific results expectations) than AEROD_v, which is a bit random.

Would anyone have a precise definition of what these two variables represent, and how they can match/differ/be put in relation?

Additionally, is there such a thing as the "AODABS" variable (discussed above) in BAM mode too?

Thanks.

Thibaut.