MM5 and older MCIP

Hi Everyone,

I have some older MM5 and MCIP data (pre version 4) but would like to run the latest version of CMAQ. The information on MCIP alludes to the fact MCIP can be modified to read MM5 data but is not offered by CMAS. If so, does anyone have a current version of MCIP that does read older MM5 data? Or, alternatively, will the current version of CMAQ read older MCIP output or is this a hard no?

Cheers, and thanks,
David Lyder


The use of MM5 with MCIP and CMAQ was phased out several years ago. Although you can technically modify MCIP and reengineer the connections to MM5, I don’t necessarily advise doing so. The primary reason is that there have been advances made to the science (particularly in the PBL and land-surface models) that we like to keep consistent between the meteorology model and CMAQ. In the case of your MM5 data, you could logistically make the connections, but the science in CMAQ will have deviated from what you have in your older MM5 simulations.

I’m not sure if the current version of CMAQ will be able to use the older MCIP output that was based on MM5. While the file formats have not changed, the requirements for input variables are likely to have changed. In addition, the dry deposition velocities are now computed in CMAQ rather than in MCIP, and (off the top of my head) I am not sure if there is any issue with the really old MCIP output.

My suggestion is that (unless this is a project where you have to use these old MM5 data for some sort of comparison) you strongly consider obtaining meteorological data using a newer version of the WRF model…whether you or your group run WRF yourselves or leverage another group’s datasets. I think that’s a better use of time than reverse-engineering MCIP to try to use older MM5 data with inferior science.

Just my $0.02.

Hi Tanya,

Thank you for your very valuable $0.02. Yes, the use of the MM5 data does allow for continuity in the project that makes addressing some questions more straightforward but I would agree that WRF, particularly the latest versions of WRF, is providing superior mesoscale met data so is probably the better option.