Opened 4 months ago

Closed 3 months ago

#3248 closed help (answered)

Error making vegfrac ancillary

Reported by: anmcr Owned by: um_support
Component: UM Mesoscale Keywords: Ancillary generation
Cc: Platform: Monsoon2
UM Version: 11.1

Description

Hello Helpdesk,

My job is u-bt436, running on Monsoon 2. It is a nested suite over a region of Antarctica, with domains at 4 km, 1.5 km, and 333 m. The model runs fine if I run with only the 4 and 1.5 km domains. However, when I add the 333 m domain, it is unable to generate the vegfrac ancillary. The error given is:

NO DATA FROM WHICH TO SET UNRESOLVED POINTS

*ERROR: No source data available in target domain

I'm afraid that I don't know how to get around this.

I did think that I could perhaps take the vegfrac ancillaries that were successfully made for the 1.5 km domain, and interpolate them to the 333 m domain, and with the aid of Xancil make the actual ancillaries.

Many thanks for your help,

Andrew

Change History (6)

comment:1 Changed 4 months ago by grenville

Hi Andrew

You can let the reconfiguration regrid the vegfrac ancillaries from the 1.5km dump — it's not clear how to do that in one step with the nesting suite.

It might be simplest to run MAKE_ANCILS_ONLY first to generate the 333m ancils (except vegfrac), then, tell the 333m task to get pre-generated ancils, and reconfigure the vegfrac from the 1.5k. I think this can be done through options files, but have not done it - does this make sense?

Grenville

comment:2 Changed 3 months ago by anmcr

Dear Grenville,

Thanks for looking at this.

I followed your advice. I thought that it was done by editing ~/app/um/rose-app.conf and changing source=3 to source=1 where appropriate, which I think instructs it to use the reconfigure from the 1.5 km ancils. But the error persisted.

However, I also edited rose cylc in /um/namelist/reconfiguration and ancillary control/configure ancils and initialise dump fields - which I used to 'set fields to zero'. I thought this would work as presumably it doesn't require any source data. But the error again persisted.

Thanks

Andrew

comment:3 Changed 3 months ago by grenville

Andrew

Your changes only apply to tasks that run after the ancil file has been created. The failure is in the generation of the ancil file. On reflection, your idea to create the 333m veg ancil appears the best - modifying the suite.rc files to apply options to a particular parameterized task looks quite ugly. If you run the suite to create ancils only (barring the veg file), you can add your file and run with the "use ancils on disk" option.
I have not tried to understand why the veg file was not created.

Grenville

comment:4 Changed 3 months ago by anmcr

Hi Grenville,

I got it to work. As I thought, it was possible to get the model to use the ancillaries successfully created at 1.5 km as input/source for the ancillaries at 333 m that were not being made (specifically qrparm.soil). However, I had to ask Stu Webster's advice to get it to work. For completeness in case anyone else runs into this problem I have copied his email/answer to me below. So please close this ticket.

Many thanks for your help,

Andrew

Andrew,

I’d just set the soil (and vegfrac if necessary) ancillaries to source=1 for the 500 m model reconfiguration. This will then mean it picks up the 1.5 km ancillary data, which is more than good enough given the errors/approximations in the source data.

Assuming you are using the same science configuration for all three resolutions then you could copy to that configuration to the expt1. i.e. copy app/um/opt/rose-app-ra1m.conf (or whatever config you’re using) to app/um/opt/rose-app-expt1.conf . Then add the ancil code from the app/um/rose-app.conf to the end of expt1.conf file, so for the latest version of the suite this is
[namelist:items(4c515841)]
ancilfilename='$UM_ANCIL_VEGFRAC_DIR/$UM_ANCIL_VEGFRAC_FILE'
domain=1
!!interval=1
l_ignore_ancil_grid_check=.true.
!!netcdf_varname='unset'
!!period=1
source=2
stash_req=216
update_anc=.false.
!!user_prog_ancil_stash_req=
!!user_prog_rconst=0.0

[namelist:items(884a098e)]
ancilfilename='$UM_ANCIL_SOIL_DIR/$UM_ANCIL_SOIL_FILE'
domain=1
!!interval=1
l_ignore_ancil_grid_check=.false.
!!netcdf_varname=10*'unset'
!!period=1
source=2
stash_req=40,41,43,44,46,47,48,207,220,223
update_anc=.false.
!!user_prog_ancil_stash_req=
!!user_prog_rconst=0.0

And change the source=2 to source=1.

Then in the 500m model configuration window make sure your change the ra1m in the drop down menu to expt1.

That should do it – although there might be more ancils you need to downscale from the 1.5 km model start dump.

So the main thing is that you have enough 500 m model ancils as it is and you just rely on the reconfiguration to pull in what the CAP could probably have given you anyway (given the 1.5 km model is comparable resolution to the source data and given the source data is likely rubbish sub-optimal!

Cheers

Stu


comment:5 Changed 3 months ago by grenville

Hi Andrew

Thanks for forward this - glad its working.

Grenville

comment:6 Changed 3 months ago by grenville

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