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WRF-LES with CBMZ/MOSAIC aerosol chemistry?


New member
Hi everyone. I am attempting to run the idealized LES test case "test/em_les" (WRF v4.4.1) with both gas and aerosol phase chemistry. Previously, I have successfully run LES simulations with CBMZ gas phase species (chem_opt = 6). However, when I switch to using one of the coupled CBMZ/MOSAIC sectional chemistry options (e.g., chem_opt = 7) I encounter segmentation faults that occur as soon as the simulation initializes. Note that the simulation only encounters a fatal error when I turn aerosol chemistry on (aerchem_onoff = 1), things run fine without the MOSAIC aerosol chemistry active.

I wanted to ask whether this is due to user error (perhaps incorrectly configured namelist parameters - please see the attached file) or whether this is a limitation of WRF-LES in terms of representing MOSAIC aerosol chemistry?

I've also included an example rsl.error output - this particular situation was run on 24 cores, but I have also tried running with 64 cores.

Thank you for your help!


  • namelist.input
    11.9 KB · Views: 8
  • rsl-error.txt
    7.7 KB · Views: 3
I believe I have found an answer to my own question. A similar issue was encountered by a user in the forum post Possible Bug with MOZART-MOSAIC scheme while writing output. The recommended solution was to set mozart_ph_diag = 1 under the &chem namelist section. The issue appears to be due to an issue with incorrect handling of pH related diagnostic data.

I've tested adding mozart_ph_diag = 1 for simulation runs using a variety of chemical mechanism options, some of which don't include MOZART however benefit from the specified parameter value.

Below is a list of chemical mechanisms which ran successfully after setting mozart_ph_diag = 1. Note that the photolysis driver for all simulations was phot_opt=1.

Chemical Mechanism
7: CBMZ/MOSAIC, 4 sectional bins
8: CBMZ/MOSAIC, 8 sectional bins
9: CBMZ/MOSAIC, 4 sectional bins, aqueous chem
10: CBMZ/MOSAIC, 8 sectional bins, aqueous chem
170: CBMZ Chemistry with MOSAIC aerosols using KPP library
201: MOZART/MOSAIC, 4 sectional bins, VBS
202: MOZART/MOSAIC, 4 sectional bins, VBS, aqueous chem