added possibility to merge monthly distributed thicknesses

oggm/sandbox/distribute_2d.py

@@ -460,8 +460,12 @@ def merge_simulated_thickness(gdirs,
         Default is gridded_simulation_merged{simulation_filesuffix}.
     simulation_filesuffix : str
         the filesuffix of the gridded_simulation file
-    years_to_merge : list | None
-        If not None, only the years in this list are merged. Default is None.
+    years_to_merge : list | xr.DataArray | None
+        If not None, and list of integers only the years at month 1 are
+        merged. You can also provide the timesteps as xarray.DataArray
+        containing calendar_year and calendar_month as it is the standard
+        output format for gridded nc files of OGGM.
+        Default is None.
     keep_dem_file
     interp
     add_topography
@@ -523,21 +527,33 @@ def _calc_bedrock_topo(fp):
 
         # then the simulated thickness files
         if years_to_merge is None:
-            # open first file to get the years
+            # open first file to get all available timesteps
             with xr.open_dataset(
                     gdirs[0].get_filepath('gridded_simulation',
                                           filesuffix=simulation_filesuffix)
             ) as ds:
-                years_to_merge = ds.time.values
+                years_to_merge = ds.time
+
+        for timestep in years_to_merge:
+            if isinstance(timestep, int):
+                year = timestep
+                month = '1'
+            elif isinstance(timestep, xr.DataArray):
+                year = int(timestep.calendar_year)
+                month = int(timestep.calendar_month)
+            else:
+                raise NotImplementedError('Wrong type for years_to_merge! '
+                                          'Should be list of int or'
+                                          'xarray.DataArray.')
 
-        for yr in years_to_merge:
             workflow.merge_gridded_data(
                 gdirs,
                 output_folder=output_folder,
-                output_filename=f"{output_filename}_{yr}",
+                output_filename=f"{output_filename}_{year}_{month:02d}",
                 input_file='gridded_simulation',
                 input_filesuffix=simulation_filesuffix,
-                included_variables=[('simulated_thickness', {'time': [yr]})],
+                included_variables=[('simulated_thickness',
+                                     {'time': [timestep]})],
                 preserve_totals=preserve_totals,
                 smooth_radius=smooth_radius,
                 use_glacier_mask=use_glacier_mask,

oggm/tests/test_models.py

@@ -5858,3 +5858,27 @@ def test_merge_simulated_thickness(self):
             ds_merged_selected_years = ds
         assert_allclose(ds_merged_selected_years.simulated_thickness.values,
                         ds_merged.loc[{'time': years_to_test}].simulated_thickness.values)
+
+        # test merging of monthly distributed data
+        workflow.execute_entity_task(run_random_climate, gdirs, y0=2014,
+                                     halfsize=5, nyears=2, seed=0,
+                                     output_filesuffix='_random_short',
+                                     store_fl_diagnostics=True)
+        workflow.execute_entity_task(
+            distribute_2d.distribute_thickness_from_simulation,
+            gdirs,
+            input_filesuffix='_random_short',
+            add_monthly=True,
+        )
+        distribute_2d.merge_simulated_thickness(
+            gdirs,
+            simulation_filesuffix='_random_short',
+            reset=True)
+        files_to_open_monthly = glob.glob(
+            os.path.join(cfg.PATHS['working_dir'],
+                         'gridded_simulation_merged_random_short*'))
+        assert len(files_to_open_monthly) == 26
+        with xr.open_mfdataset(files_to_open_monthly) as ds:
+            ds_merged_monthly = ds
+
+        assert len(ds_merged_monthly.time) == 25