Conservative interpolation using grid-box-average #33
Description
What happened?
I'm trying to interpolate healpix512 data conservatively using the MARS language, which uses MIR in the backend to interpolate.
However, our mars-client doesn't seem to recognize some of the interpolation strategies mentioned in the documentation.
I'm wondering if there's a way to directly do conservative interpolation if we clone the repository and use the MIR binary. In the past, we've done interpolations using the MIR_BINARY we have available like this:
$MIR_BINARY --grid=0.25/0.25 --intgrid=F90 --truncation=179 --area=90/0/-90/360 "$INPUT_FILE" "$OUTPUT_FILE"
What would the command look like when we want to perform conservative interpolations using an H512 input grib file instead?
As a side note, is there a way to change the MIR binary a given mars-client uses?
What are the steps to reproduce the bug?
This error occurs with a local mars client on MN5. The mars request we use to retrieve the data from the FDB looks like this:
retrieve,
class=d1,
dataset=climate-dt,
activity=HighResMIP,
experiment=cont,
date=19920101/to/19920103,
generation=1,
realization=1,
model=IFS-NEMO,
expver=a1yv,
stream=clte,
levelist=5/10,
levtype=pl,
param=129,
resolution=high,
target=input_n320.grib,
grid=N320,
time=0000/to/2300/by/0800,
type=fc,
interpolation=grid_box_average
The interpolation method will fail if it is not linear, which makes me think our MIR version may be out of date or incomplete. At least the one our MARS client is using. We run it on the supercomputer MareNostrum5 with this bash script:
#!/bin/bash
module purge
module load intel/2024.2 mkl/2024.2
MARS_CLIENT=/gpfs/projects/ehpc01/dte/mars/versions/7.0.2.8/bin/mars-client
export FDB_HOME=/gpfs/scratch/ehpc01/experiments/a1yv/fdb
N320_request=./n320_mars_request.mars
$MARS_CLIENT $N320_requestPlease note that the ordering of the retrieved H512 data is nested, which MIR seems to modify to ring.
Version
1.23.1
Platform (OS and architecture)
Red Hat Enterprise Linux 9.2 (Plow)
Relevant log output
mars - EROR - 2025-06-12 19:30:59 Exception: UserError: TypeEnum[name=interpolation]: cannot expand 'grid_box_average' Request starting line 1
mars - EROR - 2025-06-12 19:30:59 Exception: UserError: UserError: TypeEnum[name=interpolation]: cannot expand 'grid_box_average' Request starting line 1 request=retrieve,class=d1,dataset=climate-dt,activity=HighResMIP,experiment=cont,date=19920101/to/19920103,generation=1,realization=1,model=IFS-NEMO,expver=a1yv,stream=clte,levelist=5/10,levtype=pl,param=129,resolution=high,target=input_n320.grib,grid=N320,time=0000/to/2300/by/0800,type=fc,interpolation=grid_box_average, expanded=retrieve,class=d1,dataset=climate-dt,activity=highresmip,experiment=cont,date=19920101/19920102/19920103,generation=1,realization=1,model=ifs-nemo,expver=a1yv,stream=clte,levelist=5/10,levtype=pl,param=129,resolution=high,target=input_n320.grib,grid=N320,time=0000/0800/1600,type=fc
mars - EROR - 2025-06-12 19:30:59 ** UserError: UserError: TypeEnum[name=interpolation]: cannot expand 'grid_box_average' Request starting line 1 request=retrieve,class=d1,dataset=climate-dt,activity=HighResMIP,experiment=cont,date=19920101/to/19920103,generation=1,realization=1,model=IFS-NEMO,expver=a1yv,stream=clte,levelist=5/10,levtype=pl,param=129,resolution=high,target=input_n320.grib,grid=N320,time=0000/to/2300/by/0800,type=fc,interpolation=grid_box_average, expanded=retrieve,class=d1,dataset=climate-dt,activity=highresmip,experiment=cont,date=19920101/19920102/19920103,generation=1,realization=1,model=ifs-nemo,expver=a1yv,stream=clte,levelist=5/10,levtype=pl,param=129,resolution=high,target=input_n320.grib,grid=N320,time=0000/0800/1600,type=fc Caught in (/gpfs/projects/ehpc01/dte/MarsClient-7.0.2.8-Source/eckit/src/eckit/runtime/Tool.cc:31 start)
mars - EROR - 2025-06-12 19:30:59 ** Exception terminates mars-clientAccompanying data
No response
Organisation
Barcelona Supercomputing Center