Changing dtsub in CLM4

[macarew]

Hello,

I am developing a CONUS variable-resolution simulation with CLM4. When setting the recommended time step for the CONUS grid, ATM_NCPL = 384 (dtime = 225), I get the following error in the lnd.log file:
dtime_sync= 225 dtime_clm= 225 mod = 0
ENDRUN:HydrologyTracer: non integer substeps
ERROR: Unknown error submitted to shr_sys_abort.

I realize that this is because in the clm/src_clm40/biogeophys/HydrologyTracer.F90 file, dtime = 225 is not evenly divisible by dtsub = 6:
! Assign a timestep for substepping.
dtsub = dtime
! dtsub = dtime/4. ! match with flim
! dtsub = 600. ! 10 min
! dtsub = 180. ! 3 min
! dtsub = 60. ! 1 min
! dtsub = 30. ! 30 sec
dtsub = 6. ! 6 sec
if (mod(dtime,dtsub) /= 0) call endrun('HydrologyTracer: non integer substeps')
nsub = nint(dtime/dtsub)

I have removed the error by setting dtsub = 5. However, are there any other concerns/issues with setting dtsub = 5 in CLM4?

Thank you,
Sophia

 

[oleson]

I don't see the HydrologyTracer.F90 file in either the release version of cesm or the development version. And CLM4 itself is no longer supported.
Are you using some other version of the model, e.g., the isotope enabled CESM?

 

[macarew]

Yes, sorry I forgot to mention that. I am using this code base for iCESM: GitHub - NCAR/iCESM1.3_iHESP_hires: Isotope-enabled version of CESM1.3 that matches the iHESP code base.
The HydrologyTracer.F90 file I am referring to can be found here on Cheyenne: /glade/work/macarew/iCESM1.3_iHESP_hires_092222/components/clm/src_clm40/biogeophys/HydrologyTracer.F90

 

[oleson]

I'm not familiar with that code, sorry. I guess you could contact Jiang Zhu as suggested on the github site. And/or post on one of the other Forums that have answered iCESM questions in the past (i.e., search for iCESM in the Forums).