diff --git a/mlair/data_handler/data_handler_wrf_chem.py b/mlair/data_handler/data_handler_wrf_chem.py
index 736a1753d964fbcc1a07e15940d1bfa4a2fe12ae..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
 
@@ -321,7 +322,7 @@ class SingleGridColumnWrfChemDataLoader(BaseWrfChemDataLoader):
         # set geoinfo data set
         self._geo_infos = xr.Dataset({'dist': dist, 'bearing': bearing})
 
-        # set sectors
+        # set wind_sectors
         # initialize WindSector() providing helper methods for wind sector calculations
         ws = WindSector()
 
@@ -620,17 +621,17 @@ class DataHandlerSectorGrid(DataHandlerSingleGridColumn):
     # _requirements2 = remove_items(inspect.getfullargspec(DataHandlerSingleGridColumn).args, ["self", "station"])
     _requirements = DataHandlerWRF.requirements()
 
-    def __init__(self, *args, radius=None, sectors=None, wind_sector_edge_dim_name=None,  **kwargs):
+    def __init__(self, *args, radius=None, wind_sectors=None, wind_sector_edge_dim_name=None,  **kwargs):
         if radius is None:
             radius = 100  # km
         self.radius = radius
-        if sectors is None:
-            sectors = WindSector.DEFAULT_WIND_SECTORS
-        self.sectors = sectors
+        if wind_sectors is None:
+            wind_sectors = WindSector.DEFAULT_WIND_SECTORS
+        self.wind_sectors = wind_sectors
         if wind_sector_edge_dim_name is None:
             wind_sector_edge_dim_name = 'edges'
         self.wind_sector_edge_dim_name = wind_sector_edge_dim_name
-        self.windsector = WindSector(wind_sectors=self.sectors,
+        self.windsector = WindSector(wind_sectors=self.wind_sectors,
                                      wind_sector_edge_dim_name=self.wind_sector_edge_dim_name)
         self._added_vars = []
         self.wind_dir_name = None