implement create_subsets_emep in python

scripts/testdata-minimal/create_subsets_emep.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+from pathlib import Path
+
+import xarray as xr
+
+from tests.fixtures.mscw_ctm import EMEP_DATA_PATH
+
+SRC_DATA_PATH = Path("/lustre/storeB/project/fou/kl/emep/ModelRuns")
+SRC_DATA_PATH /= "2019_REPORTING/EMEP01_L20EC_rv4_33.2017"
+
+VARIABLES = ["SURF_ug_O3", "SURF_ppb_O3", "SURF_ug_PM10_rh50", "SURF_ug_PM25_rh50", "SURF_ug_NO2"]
+LAT, LON = slice(50, 52), slice(10, 12)
+
+PATHS = (
+    EMEP_DATA_PATH / "Base_day.nc",
+    EMEP_DATA_PATH / "Base_month.nc",
+    EMEP_DATA_PATH / "Base_fullrun.nc",
+)
+
+
+def reduce_dims(ds: xr.Dataset) -> xr.Dataset:
+    """crop domain and remove "unlimited" from time coordinate"""
+    del ds.encoding["unlimited_dims"]
+    return ds.isel(lon=LON, lat=LAT)
+
+
+def atomic_write(ds: xr.Dataset, path: Path, **kwargs) -> None:
+    """write dataset to a netcdf file atomically"""
+    tmp = path.with_suffix(".tmp")
+    try:
+        ds.to_netcdf(tmp, **kwargs)
+        tmp.rename(path)
+    finally:
+        tmp.unlink(missing_ok=True)
+
+
+def main():
+    for path in PATHS:
+        ds = xr.open_dataset(SRC_DATA_PATH / path.name)[VARIABLES].pipe(reduce_dims)
+        atomic_write(ds, path)
+
+
+if __name__ == "__main__":
+    main()