ERROR: map algo copy is not supported

[Yuan Sun]

What version of the code are you using?
ctsm5.3.024


Describe every step you took leading up to the problem:
Hi all,

CTSM provides a tbuildingmax time-varying input and a global mesh at 1°. For my high-resolution regional simulation, I generated stream input with a regional mesh file instead of using the default coarse stream data.

I set urbantvmapalgo = 'copy', but it returns error: ERROR: ERROR: map algo copy is not supported. The model runs with my regional stream inputs under urbantvmapalgo = 'nn'.

In the CTSM/bld/namelist_files/namelist_definition_ctsm.xml
<entry id="urbantvmapalgo" type="char*256" category="datasets"
group="urbantv_streams" valid_values="bilinear,nn,nnoni,nnonj,spval,copy" >
Mapping method from urban time varying input file to the model resolution
bilinear = bilinear interpolation
nn = nearest neighbor
nnoni = nearest neighbor on the "i" (longitude) axis
nnonj = nearest neighbor on the "j" (latitude) axis
spval = set to special value
copy = copy using the same indices
</entry>

I am wondering if only nn works? Thanks for any comments.

Best,
Yuan

 

[oleson]

It does look like the list of available options for mapalgo (for any stream, not just urbantv) has changed. Per the latest CDEPS documentation (2. Input Streams — CDEPS main documentation):

mapalgo
Specifies spatial interpolation algorithm to map stream data on stream mesh to stream data on model mesh. The used interpolation algorithm is based on the ones that are provided by ESMF library. Valid values are:

redist = Redistributes data from source mesh to destination mesh

nn = In this version of nearest neighbor interpolation each destination point is mapped to the closest source point. A given source point may go to multiple destination points, but no destination point will receive input from more than one source point.

bilinear = Bilinear interpolation. Destination value is a linear combination of the source values in the cell which contains the destination point. The weights for the linear combination are based on the distance of destination point from each source value.

consd = First-order conservative interpolation. The main purpose of this method is to preserve the integral of the field between the source and destination. Tt uses destination area normalization (ESMF_NORMTYPE_DSTAREA). Here the weights are calculated by dividing the area of overlap of the source and destination cells by the area of the entire destination cell.

consf = Same with consd but in this case it uses fraction area normalization (ESMF_NORMTYPE_FRACAREA). Here in addition to the weight calculation done for destination area normalization the weights are also divided by the fraction that the destination cell overlaps with the entire source grid.

There is a CTSM issue that has yet to be implemented regarding this newer list:

List of mapalgo options for streams is different for MCT than NUOPC, currently we are using the MCT list · Issue #1912 · ESCOMP/CTSM

Brief summary of bug The list of options for the mapalgo namelist fields in CTSM is the list for MCT, rather than NUOPC. Since, we are moving to NUOPC we should update it to the NUOPC list and remo...

github.com

I'm not sure what redist does exactly, but note there is another issue associated with using anything other than "nn", specifically associated with urbantvmapalgo:

Adds a broadcast of the namelist value 'urbantvmapalgo' by briandobbins · Pull Request #2534 · ESCOMP/CTSM

Adds a broadcast of the namelist value (urbantvmapalgo) after reading it in so it is consistent across all ranks when not using the default value ('nn'). Description of changes Simple one-l...

github.com

 

[Yuan Sun]

Hi Keith,

Thanks for clarifying this point. Since it is still under development using ESMF, I will use 'nn' so far.

Best,
Yuan