[Bug]: Regrid2Regridder yields NANs

[ShihengDuan]

Originally discussed here: #598

What happened?

Initially I have a problem with Regrid2Regridder since it shows NANs: Regrid2Regridder.

When I try to create an example, I found that if the target_grid only has one variable, it works well. I'm not sure if this is related to this.

Code:

import xarray as xa
import xcdat as xc
from xcdat.regridder.regrid2 import Regrid2Regridder
from xcdat.regridder.xesmf import XESMFRegridder
from matplotlib import pyplot as plt

print(xc.__version__)
ua = xc.open_dataset('UA_swe.nc')
vic_ele = xc.open_dataset('vic_elev.nc')
vic_grid = xc.open_dataset('/p/lustre1/shiduan/HydroSimulation/VIC/VIC/samples/domain.vic.WUS.0625deg.nc')
print(vic_grid)
vic_ele.lat.attrs['standard_name'] = 'Y'
vic_ele.lon.attrs['standard_name'] = 'X'
vic_grid.lat.attrs['standard_name'] = 'Y'
vic_grid.lon.attrs['standard_name'] = 'X'
ua.lat.attrs['standard_name'] = 'Y'
ua.lon.attrs['standard_name'] = 'X'
regrid2_gridder_single = Regrid2Regridder(ua, vic_ele)
regrid2_gridder_all = Regrid2Regridder(ua, vic_grid)

regrid2_swe_single = regrid2_gridder_single.horizontal("SWE", ua)
regrid2_swe_single.SWE.isel(time=10).plot()
plt.show()

regrid2_swe_all = regrid2_gridder_all.horizontal("SWE", ua)
regrid2_swe_all.SWE.isel(time=10).plot()
plt.show()

vic_ele is the elevation data extracted from vic_grid.

2024-02-02 17:38:17,872 [WARNING]: dataset.py(open_dataset:128) >> "No time coordinates were found in this dataset to decode. If time coordinates were expected to exist, make sure they are detectable by setting the CF 'axis' or 'standard_name' attribute (e.g., ds['time'].attrs['axis'] = 'T' or ds['time'].attrs['standard_name'] = 'time'). Afterwards, try decoding again with `xcdat.decode_time`."
2024-02-02 17:38:17,872 [WARNING]: dataset.py(open_dataset:128) >> "No time coordinates were found in this dataset to decode. If time coordinates were expected to exist, make sure they are detectable by setting the CF 'axis' or 'standard_name' attribute (e.g., ds['time'].attrs['axis'] = 'T' or ds['time'].attrs['standard_name'] = 'time'). Afterwards, try decoding again with `xcdat.decode_time`."
2024-02-02 17:38:17,898 [WARNING]: dataset.py(open_dataset:128) >> "No time coordinates were found in this dataset to decode. If time coordinates were expected to exist, make sure they are detectable by setting the CF 'axis' or 'standard_name' attribute (e.g., ds['time'].attrs['axis'] = 'T' or ds['time'].attrs['standard_name'] = 'time'). Afterwards, try decoding again with `xcdat.decode_time`."
2024-02-02 17:38:17,898 [WARNING]: dataset.py(open_dataset:128) >> "No time coordinates were found in this dataset to decode. If time coordinates were expected to exist, make sure they are detectable by setting the CF 'axis' or 'standard_name' attribute (e.g., ds['time'].attrs['axis'] = 'T' or ds['time'].attrs['standard_name'] = 'time'). Afterwards, try decoding again with `xcdat.decode_time`."
0.6.1
<xarray.Dataset>
Dimensions:   (lon: 312, lat: 264, bnds: 2)
Coordinates:
  * lon       (lon) float64 -123.0 -122.9 -122.8 -122.8 ... -103.7 -103.6 -103.5
  * lat       (lat) float64 32.53 32.59 32.66 32.72 ... 48.78 48.84 48.91 48.97
Dimensions without coordinates: bnds
Data variables:
    elev      (lat, lon) float64 ...
    mask      (lat, lon) int32 ...
    frac      (lat, lon) float64 ...
    area      (lat, lon) float64 ...
    lon_bnds  (lon, bnds) float64 -123.0 -122.9 -122.9 ... -103.6 -103.6 -103.5
    lat_bnds  (lat, bnds) float64 32.5 32.56 32.56 32.62 ... 48.94 48.94 49.0
Attributes:
    title:         VIC domain data
    Conventions:   CF-1.6
    history:       created by shiduan, 2023-11-14 11:56:44.828806
    user_comment:  VIC domain data
    source:        generated from VIC North American 1/16 deg. model paramete...

What I get:

What did you expect to happen? Are there are possible answers you came across?

No response

Minimal Complete Verifiable Example (MVCE)

No response

Relevant log output

No response

Anything else we need to know?

Example files:
UA_swe.nc
domain.vic.WUS.0625deg.nc
vic_ele.nc

Environment

INSTALLED VERSIONS

commit: None
python: 3.9.15 | packaged by conda-forge | (main, Nov 22 2022, 08:45:29)
[GCC 10.4.0]
python-bits: 64
OS: Linux
OS-release: 4.18.0-513.9.1.1toss.t4.x86_64
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: 1.12.1
libnetcdf: 4.8.1

xarray: 2023.1.0
pandas: 1.5.3
numpy: 1.26.3
scipy: 1.12.0
netCDF4: 1.5.8
pydap: None
h5netcdf: None
h5py: None
Nio: None
zarr: None
cftime: 1.6.3
nc_time_axis: 1.4.1
PseudoNetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: None
dask: 2022.6.1
distributed: 2022.6.1
matplotlib: 3.3.2
cartopy: 0.21.0
seaborn: None
numbagg: None
fsspec: 2023.12.2
cupy: None
pint: None
sparse: 0.15.1
flox: None
numpy_groupies: None
setuptools: 69.0.3
pip: 23.3.2
conda: None
pytest: None
mypy: None
IPython: 8.12.0
sphinx: None

[pochedls]

I can't reproduce this (datasets aren't readable/publicly accessible with full path names).

This may not be the issue, but have you tried calling the regridder as is shown in the docs?

[ShihengDuan]

xcdat-test.zip
It seems I cannot upload nc files directly but this should work.

[lee1043]

The above is what I am getting when running @ShihengDuan's code above with the latest main branch after #533 being merged. @ShihengDuan Does this look reasonable to you?

[ShihengDuan]

Yes I think this makes sense to me. Thanks!

[lee1043]

@ShihengDuan thanks for confirming! I am closing this issue but please feel free to reopen when you have any further issue.