aerodynamic parameter error in UrbanFluxes

[raeder]

I'm running CAM4 in data assimilation mode, so it's a series of 12 hour forecasts,
started from the result of the previous forecast. The series has finished 27 days,
but on the 28th I got this error message in the printed output in the 2nd timestep:
--------------
(GETFIL): using /fis/cgd/cseg/csm/inputdata/lnd/clm2/surfdata/surfdata_0.9x1.25_simyr2000_c091006.nc
Successfully read monthly vegetation data for
month 9

aerodynamic parameter error in UrbanFluxes
h_u - z_d

 

[oleson]

This error means that the forcing height at the lowest atmospheric level in CAM is less than the sum of roughness length plus displacement height. The roughness length and displacement height look reasonable but the forcing height must be negative for some reason. This is passed to CLM from CAM. If you have CLM history file output you could look at "ZBOT" which is the forcing height to see how it is evolving in your simulation. Or look at the CAM history file.

Kevin, you can stop by my office and we can talk about this further if you want.

Keith Oleson

 

[raeder]

Thanks Keith,

I'll try to generate some more diagnostics before taking your time.
It's a big help to know which variables to follow, without having to
trace it through the code.

Kevin

 

[raeder]

I found that my scripts were choosing CLM restart files which were 12 hours earlier
than they should have used. I believe that the inconsistency between the radiation
fields of the CLM and atmosphere caused this error message, but that's just a guess.

Kevin

 

[mburt@atmos_colostate_edu]

I am trying to run PORT as well and received the same error message: aerodynamic parameter error in UrbanFluxes  30: h_u - z_d

 

[joakim_langner@smhi_se]

I have exactly the same problems trying to run PORT using CESM 1.2. I use an F compset. If you find a solution please let me know./Joakim

 

[apgrass]

I had a similar problem and got it to work by setting the compset to CAM with all other components stubs. See my comment here: https://bb.cgd.ucar.edu/comment/1007794#comment-1007794