Conditions to match ref.time & hist.time, and also ref.time.size & sim.time.size

CHANGELOG.rst

@@ -4,7 +4,7 @@ Changelog
 
 v0.54.0 (unreleased)
 --------------------
-Contributors to this version: Trevor James Smith (:user:`Zeitsperre`), Pascal Bourgault (:user:`aulemahal`).
+Contributors to this version: Trevor James Smith (:user:`Zeitsperre`), Pascal Bourgault (:user:`aulemahal`), Éric Dupuis (:user:`coxipi`).
 
 Breaking changes
 ----------------
@@ -17,6 +17,7 @@ Bug fixes
 Internal changes
 ^^^^^^^^^^^^^^^^
 * Changed french translations with word "pluvieux" to "avec précipitations". (:issue:`1960`, :pull:`1994`).
+* Using different time for `ref` and `hist` is now explicitly forbidden in many bias adjustment methods (e.g. `EmpiricalQuantileMapping`). (:issue:`1903`, :pull:`1995`)
 
 v0.53.2 (2024-10-31)
 --------------------

xclim/sdba/adjustment.py

@@ -207,6 +207,12 @@ def __convert_units_to(_input_da, _internal_dim, _internal_target):
             convert_units_to(inda, target, context="infer") for inda in inputs
         ), target
 
+    @classmethod
+    def _check_matching_time(cls, ref, hist):
+        """Raise an error ref and hist times don't match."""
+        if all(ref.time == hist.time) is False:
+            raise ValueError("`ref` and `hist` should have the same time arrays.")
+
     @classmethod
     def _train(cls, ref, hist, **kwargs):
         raise NotImplementedError()
@@ -258,6 +264,9 @@ def train(cls, ref: DataArray, hist: DataArray, **kwargs) -> TrainAdjust:
         else:
             train_units = ""
 
+        if cls._allow_diff_calendars is False:
+            cls._check_matching_time(ref, hist)
+
         ds, params = cls._train(ref, hist, **kwargs)
         obj = cls(
             _trained=True,
@@ -1737,6 +1746,8 @@ class MBCn(TrainAdjust):
     Only  "time" and "time.dayofyear" (with a suitable window) are implemented as possible values for `group`.
     """
 
+    _allow_diff_calendars = False
+
     @classmethod
     def _train(
         cls,