Cannot obtain CAM monthly history files with more than one time entry

[BenT]

I'm running a basic F2000climo in 2.1.5, just trying to get the output configured.

In order to get some monthly variables, and write more than one month in a single NetCDF file, I have added the following to my user_nl_cam file:

&cam_history_nl
nhtfrq = 0, 0
mfilt = 1, 120
avgflag_pertape = 'A', 'A'
fincl2 = 'PRECL','PRECC','PRECT','PRECTMX','TREFHT','TREFHTMX','TREFHTMN',
'TS','TSMX','TSMN','PSL','RELHUM','CLDTOT','CLDLOW','CLDMED',
'CLDHGH','FSNS','FLNS','FSNT','FSNTOAC','FLNT','LHFLX','SHFLX','TAUX','TAUY',
'FSDS','FSDSC','SST','OMEGA','ZBOT'
/

This is reflected in the ./run/atm_in.

&cam_history_nl
avgflag_pertape = 'A','A'
fincl2 = 'PRECL', 'PRECC', 'PRECT', 'PRECTMX', 'TREFHT', 'TREFHTMX', 'TREFHTMN', 'TS', 'TSMX', 'TSMN', 'PSL', 'RELHUM',
'CLDTOT', 'CLDLOW', 'CLDMED', 'CLDHGH', 'FSNS', 'FLNS', 'FSNT', 'FSNTOAC', 'FLNT', 'LHFLX', 'SHFLX', 'TAUX',
'TAUY', 'FSDS', 'FSDSC', 'SST', 'OMEGA', 'ZBOT'
mfilt = 1,120
nhtfrq = 0,0
/

However, when I run for 100 days, I have not been able to obtain output history files with more than a single sample entry (i.e. a single month). Output is (3) single monthly h1 files.

What am I doing wrong? Thanks!

 

[BenT]

Since it appears I was doing nothing "wrong" and I wasted a whole bunch of time on this, I'll answer my own question.

I was confident that I had made a simple formatting error, but Claude (after getting it wrong twice) and I eventually figured out apparently monthly files are hard coded to a single time step. So, it appears that mfilt is ignored where nhtfrq = 0. My goodness what a ridiculous "feature" without documentation.

CAM and CLM output frequency

 

[slevis]

Looking into this a bit, I get the sense that you can modify mfilt in the land model, even for primary monthly history files. See this example:

1.2.3. Customizing CLM's namelist — ctsm release-clm5.0 documentation

I ran a test to confirm, which worked.

 

[BenT]

Ok, good to know, thanks. I can work with lots of monthly files but it is frustrating the guidance does not note the apparent deficiency with CAM. Indeed, the tutorial below even highlights the importance of setting mfilt to an appropriate value, without noting that the frequency of monthly data cannot be changed. I get that this is more important for higher frequency data, but anyway...
Customize CAM output — CESM Tutorial