I decided to also look at what happens when you plot with contourf. In this case both the plot of the original data and the interpolated data have a white line at the central longitude, but the interpolated data also has white lines at the poles:

Original MPI-ESM

Interpolated MPI-ESM

Here's the code that produced the plots:

```python import xarray as xr import matplotlib.pyplot as plt import cartopy.crs as ccrs

cesm2_waccm = xr.open_dataset('pr_day_CESM2-WACCM_ssp245_r2i1p1f1_gn_20750101-20841231.nc') mpi = xr.open_dataset('pr_day_MPI-ESM1-2-LR_ssp245_r1i1p1f1_gn_20750101-20941231.nc')

cesm2_waccm_subset = cesm2_waccm.sel(time=slice('2075-01-01', '2075-12-31')).mean(dim='time') mpi_subset = mpi.sel(time=slice('2075-01-01', '2075-12-31')).mean(dim='time')

map_proj = ccrs.PlateCarree()

Now this also produces a white line.

plot = mpi_subset.pr.plot.contourf(subplot_kws={'projection': map_proj}) plot.axes.coastlines() plt.show()

mpi_interp = mpi_subset.interp(lat=cesm2_waccm_subset['lat'], lon=cesm2_waccm_subset['lon'])

Has a white line at the central longitude.

plot = mpi_interp.pr.plot.contourf(subplot_kws={'projection': map_proj}) plot.axes.coastlines() plt.show() ```