diff --git a/src/rook/utils/concat_utils.py b/src/rook/utils/concat_utils.py
index 1585da5..65e3357 100644
--- a/src/rook/utils/concat_utils.py
+++ b/src/rook/utils/concat_utils.py
@@ -89,7 +89,9 @@ def _calculate(self):
         datasets = []
         for ds_id in norm_collection.keys():
             ds = norm_collection[ds_id]
-            ds_mod = apply_decadal_fixes(ds_id, ds)
+            ds_mod = apply_decadal_fixes(
+                ds_id, ds, output_dir=self.params.get("output_dir", ".")
+            )
             datasets.append(ds_mod)
 
         dims = dimension_parameter.DimensionParameter(
diff --git a/src/rook/utils/decadal_fixes.py b/src/rook/utils/decadal_fixes.py
index 5dc6c5e..686f325 100644
--- a/src/rook/utils/decadal_fixes.py
+++ b/src/rook/utils/decadal_fixes.py
@@ -1,4 +1,6 @@
 import xarray as xr
+import os
+import tempfile
 
 from roocs_utils.xarray_utils.xarray_utils import open_xr_dataset
 
@@ -47,8 +49,8 @@ def get_decadal_model_attr_from_dict(ds_id, ds, attr):
     return value
 
 
-def apply_decadal_fixes(ds_id, ds):
-    ds_mod = decadal_fix_calendar(ds_id, ds)
+def apply_decadal_fixes(ds_id, ds, output_dir=None):
+    ds_mod = decadal_fix_calendar(ds_id, ds, output_dir=output_dir)
     ds_mod = decadal_fix_1(ds_id, ds_mod)
     ds_mod = decadal_fix_2(ds_id, ds_mod)
     ds_mod = decadal_fix_3(ds_id, ds_mod)
@@ -137,13 +139,16 @@ def decadal_fix_5(ds_id, ds):
     return ds_mod
 
 
-def decadal_fix_calendar(ds_id, ds):
+def decadal_fix_calendar(ds_id, ds, output_dir=None):
     # set proleptic_gregorian calendar to gregorian (standard).
     # the proleptic gregorian calendar extends the gregorin backward in time before 1582.
     calendar = ds.time.encoding.get("calendar", "standard")
     if calendar == "proleptic_gregorian":
         ds.time.encoding["calendar"] = "standard"
         # need to write and read file to rewrite time dimension for the standard calendar!
-        ds.to_netcdf("fixed_calendar.nc")
-        ds = open_xr_dataset("fixed_calendar.nc")
+        tmp_dir = tempfile.TemporaryDirectory(dir=output_dir)
+        fixed_nc = os.path.join(tmp_dir, "fixed_calendar.nc")
+        ds.to_netcdf(fixed_nc)
+        ds = open_xr_dataset(fixed_nc)
+        tmp_dir.cleanup()
     return ds