diff --git a/mlair/data_handler/data_handler_wrf_chem.py b/mlair/data_handler/data_handler_wrf_chem.py
index dbbbcd992b40f93268094ed223dbdda1a279c714..fd126129a577f6b24200c55b088dd29cc58b0069 100644
--- a/mlair/data_handler/data_handler_wrf_chem.py
+++ b/mlair/data_handler/data_handler_wrf_chem.py
@@ -118,9 +118,10 @@ class BaseWrfChemDataLoader:
 
     @TimeTrackingWrapper
     def open_data(self):
-        # logging.debug(f'open data: {self.dataset_search_str}')
+        # see also https://github.com/pydata/xarray/issues/1385#issuecomment-438870575
         data = xr.open_mfdataset(paths=self.dataset_search_str, combine='nested', concat_dim=self.time_dim_name,
-                                 parallel=True)
+                                 parallel=True, decode_cf=False)
+        data = xr.decode_cf(data)
         self._data = data
 
     def assign_coords(self, coords, **coords_kwargs):
@@ -292,7 +293,7 @@ class SingleGridColumnWrfChemDataLoader(BaseWrfChemDataLoader):
         if self.external_coords_file is not None:
             self._apply_external_coordinates()
         self.apply_staged_transormation()
-        self.rechunk_data(self.rechunk_values)
+        #self.rechunk_data(self.rechunk_values)
         self._set_geoinfos()
         return self