fix forcing nc files left unclosed

modules/data_processing/forcings.py

@@ -223,7 +223,12 @@ def compute_zonal_stats(
             concatenated_da.to_dataset(name=variable).to_netcdf(forcings_dir/ "temp" / f"{variable}_{i}.nc")
         # Merge the chunks back together
         datasets = [xr.open_dataset(forcings_dir / "temp" / f"{variable}_{i}.nc") for i in range(len(time_chunks))]
-        xr.concat(datasets, dim="time").to_netcdf(forcings_dir / f"{variable}.nc")
+        result = xr.concat(datasets, dim="time")
+        result.to_netcdf(forcings_dir / f"{variable}.nc")
+        # close the datasets
+        result.close()
+        _ = [dataset.close() for dataset in datasets]
+
         for file in forcings_dir.glob("temp/*.nc"):
             file.unlink()
         progress.remove_task(chunk_task)
@@ -237,6 +242,7 @@ def compute_zonal_stats(
     )
     write_outputs(forcings_dir, variables)
 
+
 def write_outputs(forcings_dir, variables):
 
     # start a dask cluster if there isn't one already running
@@ -289,9 +295,9 @@ def write_outputs(forcings_dir, variables):
     final_ds["Time"].attrs["epoch_start"] = "01/01/1970 00:00:00" # not needed but suppresses the ngen warning
 
     final_ds.to_netcdf(output_folder / "forcings.nc", engine="netcdf4")
-    # delete the individual variable files
-    for file in forcings_dir.glob("*.nc"):
-        file.unlink()
+    # close the datasets
+    _ = [result.close() for result in results]
+    final_ds.close()
 
 
 def setup_directories(cat_id: str) -> file_paths: