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Runoff Units

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Hi All,

I'm investigating the hydrological performance of CLMv4 using the WRF-CLM modeling suite. And, I'm running into issues with some of the variables, like the following:

The units for runoff (variable name: SRFOFF) using CLM are listed as [mm], but the values seem too small. In the land surface model code (~/WRFV3/phys/module_sf_clm.F), the variables that account for total runoff (i.e., qflx_surf, and others) have units of [mm H2O /s]. These units seem more appropriate for the values of runoff that are produced by the model. I'm curious whether the SRFOFF variable could be mislabeled.

Does anyone have any experience with this? Is this as simple as an error in unit labeling? Is there any conversion done in writing the model output? Can anyone confirm/deny my suspicions about the units?

I believe the variable in question "SRFOFF" must come from the Community Land Model side, as it's not a variable listed in the WRF code. You may need to contact someone in the development/support group for them to get an answer to this question.
Hi kwerner,

Do you have a suggested contact? I've reached out to the CLM group in the past, and they said that they do not maintain the wrf version of CLM, and that there are differences between the WRF version and the CESM version. Do you know who develops and maintains CLM in WRF?


I apologize for the delay. I asked our physics specialist about a contact, but they responded with:
Is it always increasing with time?
It looks like it should be an accumulated value (qsfxy) in the code

I can relay the answer back to them and see if they are able to help any further.