Bug report for the unreasonable land co2 level when using B20TRC5 compsets

[zhu467@purdue_edu]

Hi All, I find a bug when running B20TRC5 with CESM1.2.2. I use the default setup but when I looked into lnd.log file I find the first year's  CO2 volume mixing ratio is 355 umol/mol. Since this compsets is running from 1850, the co2 level should have a lower value about 285ppm. I think there must be something wrong with the data transfering between the components.The information in the lnd.log file is as the follwoing: atmospheric forcing data is from cesm atm model
 Restart parameters:
    restart pointer file directory     = .
    restart pointer file name          = rpointer.lnd
 Large file support for output files is ON
 model physics parameters:
    CO2 volume mixing ratio   (umol/mol)   =    355.000000000000   

 

[klindsay]

Hi,The value reported on the line 'CO2 volume mixing ratio' is misleading when co2_type is diagnostic. There is a variable in the CLM output named PCO2. It is the CO2 value used by the land model, in units of Pa. CO2 in ppmv is 1e6*PCO2/PBOT. This expression is consistent with co2 passed by CAM.Keith