O3 and CO2 in radiation computations

[swahl@geomar_de]

Dear all

sorry for asking another question, but the following came up today in a discussion and it's essential for us to know for planning future experiments with CESM 1.2.0
We currently have a setup with the B_1955-2005_WACCM_CN compset. Questions:
- How is the O3 (ozone) dealt with in the radiation (camrt) code. Is the 3D structure from the MOZART chemistry used in the radiation calculations or are they any simplifications applied before doing the radiative transfer calculations? We looked extensively at the source code and came to the conclusion that the full 3D ozone information is used in the radiation calculation. Can someone confirm this?
- Is the a difference between upper (WACCM) and lower atmosphere (CAM) on how ozone is treated in the radiation?
- How does it work with the CO2? As the above compset contains a carbon cycle we do have 3D CO2 distribution which is reduced to (lat,lon) via " call calc_col_mean(state, co2, co2_col_mean)" in radiation.F90. So does the real 3D structure go into the radiation? (Or is just the value from the external GHG forcing file used (e.g. CO2 from ghg_rcp45_1960clim_c110503.nc in case one uses "climatological" CO2)?)
A simple yes/no answer is sufficient as we just want to make sure we got everything right.

 

[santos]

I have moved this to the WACCM forum, as it is more likely to be noticed there.

 

[santos]

I have moved this to the WACCM forum, as it is more likely to be noticed there.

 

[mmills]

WACCM uses the calculated, 3D O3 and CO2 fields in the radiation calculation. Below ~65 km, radiation is done by CAMRT. Above that altitude, WACCM does its own radiation calculations to account, among other things, for non-instantaneous/non-local thermalization of absorbed short-wave radiation, and for non-LTE effects in the long-wave calculation.More details are available in section 5.6.6 Radiation of the CAM5 Scientific Description. A talk presented by Andrew Conley at the February 2011 Whole Atmosphere Working Group Meeting includes some helpful plots. Another talk he gave at the 2011 CESM workshop might also be helpful. 

 

[mmills]

WACCM uses the calculated, 3D O3 and CO2 fields in the radiation calculation. Below ~65 km, radiation is done by CAMRT. Above that altitude, WACCM does its own radiation calculations to account, among other things, for non-instantaneous/non-local thermalization of absorbed short-wave radiation, and for non-LTE effects in the long-wave calculation.More details are available in section 5.6.6 Radiation of the CAM5 Scientific Description. A talk presented by Andrew Conley at the February 2011 Whole Atmosphere Working Group Meeting includes some helpful plots. Another talk he gave at the 2011 CESM workshop might also be helpful. 

 

[mmills]

I should add that CESM1.2 has no scientifically validated configurations. If you wish to publish science from your model output, you should use CESM1.0.5, which has the same climate as our published CMIP5 runs. Otherwise, if you publish results using CESM1.2, you should validate the model yourself by comparison to our CMIP5 runs.

 

[mmills]

I should add that CESM1.2 has no scientifically validated configurations. If you wish to publish science from your model output, you should use CESM1.0.5, which has the same climate as our published CMIP5 runs. Otherwise, if you publish results using CESM1.2, you should validate the model yourself by comparison to our CMIP5 runs.