Fix CORDEX ALADIN53 tas coordinates

esmvalcore/cmor/_fixes/cordex/cnrm_cerfacs_cnrm_cm5/aladin53.py

@@ -4,6 +4,8 @@
 
 from typing import TYPE_CHECKING
 
+import iris.coord_systems
+
 from esmvalcore.cmor.fix import Fix
 
 if TYPE_CHECKING:
@@ -30,3 +32,25 @@ def fix_metadata(self, cubes: Sequence[Cube]) -> Sequence[Cube]:
             cube.units = "deg_C"
             cube.convert_units(self.vardef.units)
         return cubes
+
+
+class AllVars(Fix):
+    """Fixes for all variables."""
+
+    def fix_metadata(self, cubes: Sequence[Cube]) -> Sequence[Cube]:
+        for cube in cubes:
+            if self.extra_facets.get("domain") == "EUR-11":
+                # Set false_easting and false_northing to 0.0, as odd values
+                # have been observed in some files.
+                coord_system = iris.coord_systems.LambertConformal(
+                    central_lat=49.5,
+                    central_lon=10.5,
+                    secant_latitudes=(49.5,),
+                )
+                for coord_name in [
+                    "projection_x_coordinate",
+                    "projection_y_coordinate",
+                ]:
+                    if cube.coords(coord_name):
+                        cube.coord(coord_name).coord_system = coord_system
+        return cubes

esmvalcore/cmor/_fixes/cordex/cordex_fixes.py

@@ -12,6 +12,7 @@
 import iris.coords
 import iris.cube
 import iris.exceptions
+import iris.util
 import numpy as np
 import pyproj
 from cf_units import Unit
@@ -293,6 +294,18 @@ def _use_standard_lambert_conformal_grid(
         )
         y_coord.guess_bounds()
 
+        # If the original coordinate was not monotonic, it has been downgraded
+        # to an auxiliary coordinate, so promote it back to a dimension
+        # coordinate.
+        iris.util.promote_aux_coord_to_dim_coord(
+            cube,
+            "projection_x_coordinate",
+        )
+        iris.util.promote_aux_coord_to_dim_coord(
+            cube,
+            "projection_y_coordinate",
+        )
+
         # Define the transformation from projection coordinates to
         # geographic coordinates.
         transformer = pyproj.Transformer.from_crs(

tests/integration/cmor/_fixes/cordex/test_cnrm_cerfacs_cnrm_cm5.py

@@ -1,8 +1,10 @@
 """Tests for the fixes for driver CNRM-CERFACS-CNRM-CM5."""
 
 import iris
+import iris.coord_systems
 import iris.coords
 import iris.cube
+import numpy as np
 import pytest
 
 from esmvalcore.cmor._fixes.cordex.cnrm_cerfacs_cnrm_cm5 import (
@@ -90,6 +92,60 @@ def test_fix_aladin53_ts() -> None:
     assert result.units == "K"
 
 
+def test_fix_aladin53_tas() -> None:
+    fixes = Fix.get_fixes(
+        "CORDEX",
+        "ALADIN53",
+        "day",
+        "tas",
+        extra_facets={
+            "driver": "CNRM-CERFACS-CNRM-CM5",
+            "domain": "EUR-11",
+        },
+    )
+    assert isinstance(fixes[0], aladin53.AllVars)
+    wrong_coord_system = iris.coord_systems.LambertConformal(
+        central_lat=49.5,
+        central_lon=10.5,
+        secant_latitudes=(49.5,),
+        false_easting=400000.0,
+        false_northing=-100000.0,
+    )
+    cube = iris.cube.Cube(
+        np.array([0, 1.0]).reshape(1, 2),
+        var_name="tas",
+        units="K",
+        aux_coords_and_dims=[
+            (
+                iris.coords.AuxCoord(
+                    [0.0],
+                    standard_name="projection_y_coordinate",
+                    units="m",
+                    coord_system=wrong_coord_system,
+                ),
+                (0,),
+            ),
+            (
+                iris.coords.AuxCoord(
+                    [0.0, 1.0],
+                    standard_name="projection_x_coordinate",
+                    units="m",
+                    coord_system=wrong_coord_system,
+                ),
+                (1,),
+            ),
+        ],
+    )
+    (result,) = fixes[0].fix_metadata([cube])
+    assert result.coord_system() == iris.coord_systems.LambertConformal(
+        central_lat=49.5,
+        central_lon=10.5,
+        secant_latitudes=(49.5,),
+        false_easting=0,
+        false_northing=0,
+    )
+
+
 @pytest.mark.parametrize("short_name", ["pr", "tas"])
 def test_get_aladin63_fix(short_name):
     fix = Fix.get_fixes(

tests/integration/cmor/_fixes/cordex/test_cordex_fixes.py

@@ -298,8 +298,12 @@ def test_lambert_conformal_grid_fix(use_standard_grid: bool) -> None:
                 ),
                 1,
             ),
+        ],
+        aux_coords_and_dims=[
+            # If the x coordinate is not monotonic, it may be demoted to an
+            # auxiliary coordinate on load.
             (
-                iris.coords.DimCoord(
+                iris.coords.AuxCoord(
                     np.arange(0, 453),
                     var_name="projection_x_coordinate",
                     standard_name="projection_x_coordinate",
@@ -308,8 +312,6 @@ def test_lambert_conformal_grid_fix(use_standard_grid: bool) -> None:
                 ),
                 2,
             ),
-        ],
-        aux_coords_and_dims=[
             (
                 iris.coords.AuxCoord(
                     np.ones((453, 453)),
@@ -344,8 +346,8 @@ def test_lambert_conformal_grid_fix(use_standard_grid: bool) -> None:
     ]:
         assert len(result.coords(coord_name)) == 1
 
-    x_coord = result.coord("projection_x_coordinate")
-    y_coord = result.coord("projection_y_coordinate")
+    x_coord = result.coord("projection_x_coordinate", dim_coords=True)
+    y_coord = result.coord("projection_y_coordinate", dim_coords=True)
     assert x_coord.units == "m"
     assert y_coord.units == "m"
     assert x_coord.points.dtype == np.float64

tests/integration/cmor/_fixes/test_fix.py

@@ -10,6 +10,9 @@
 from esmvalcore.cmor._fixes.cmip5.canesm2 import FgCo2
 from esmvalcore.cmor._fixes.cmip5.cesm1_bgc import Gpp
 from esmvalcore.cmor._fixes.cmip6.cesm2 import Omon, Tos
+from esmvalcore.cmor._fixes.cordex.cnrm_cerfacs_cnrm_cm5.aladin53 import (
+    AllVars as Aladin53AllVars,
+)
 from esmvalcore.cmor._fixes.cordex.cnrm_cerfacs_cnrm_cm5.aladin63 import (
     Tas,
 )
@@ -53,7 +56,7 @@ def test_get_grid_fix_cordex():
         "tas",
         extra_facets={"driver": "CNRM-CERFACS-CNRM-CM5"},
     )
-    assert fix == [AllVars(None), GenericFix(None)]
+    assert fix == [Aladin53AllVars(None), AllVars(None), GenericFix(None)]
 
 
 def test_get_fixes_with_replace():