Compatibility of CMAQv5.5 with WRFv4 and Different MCIP Versions

CMAQ
1

Hi everyone,
I have two questions regarding the compatibility of CMAQv5.5 with different MCIP versions and the impact of WRF vertical coordinate systems on CH4 simulations.

  1. Compatibility of CMAQv5.5 with MCIPv4.5
    Is CMAQv5.5 compatible with WRFv4 using the traditional terrain-following (non-hybrid) vertical coordinate system and MCIPv4.5?
    I am considering using MCIPv4.5 because it allows vertical layer reduction, which could significantly reduce the computational cost of CMAQ simulations. Are there any known compatibility issues or potential impacts on simulation accuracy when using MCIPv4.5 with CMAQv5.5?
  2. Impact of WRF vertical coordinates on CH4 simulations
    I have also noticed substantial differences in simulated CH4 concentrations when using CMAQv5.5 + MCIPv5.5 with WRF configured with either traditional terrain-following or hybrid vertical coordinates.
    Specifically, compared with the traditional terrain-following coordinate system, the hybrid coordinate system produces higher CH4 concentrations in the upper layers but lower concentrations in the lower layers. In some cases, the differences can exceed 100 ppb.
    Given these substantial differences, I would like to know which vertical coordinate system is generally more appropriate or recommended for regional CH4 simulations using CMAQv5.5.
    I would greatly appreciate any suggestions or experiences regarding these two issues.
    Thank you very much for your help!