fix radius scaling tests

Author: rajeeja

test/core/test_vector_calculus.py

@@ -152,11 +152,14 @@ def test_gradient_scales_by_radius(self, gridpath, datasetpath):
         grad_unit = uxds["gaussian"].gradient(scale_by_radius=False)
 
         nt.assert_allclose(
-            grad_scaled["zonal_gradient"], grad_unit["zonal_gradient"] / radius
+            grad_scaled["zonal_gradient"],
+            grad_unit["zonal_gradient"] / radius,
+            equal_nan=True,
         )
         nt.assert_allclose(
             grad_scaled["meridional_gradient"],
             grad_unit["meridional_gradient"] / radius,
+            equal_nan=True,
         )
 
 
@@ -554,7 +557,7 @@ def test_curl_scales_by_radius(self, gridpath, datasetpath):
         curl_scaled = u_component.curl(v_component)
         curl_unit = u_component.curl(v_component, scale_by_radius=False)
 
-        nt.assert_allclose(curl_scaled, curl_unit / radius)
+        nt.assert_allclose(curl_scaled, curl_unit / radius, equal_nan=True)
 
     def test_curl_units_and_attributes(self, gridpath, datasetpath):
         """Test that curl preserves appropriate units and attributes"""

uxarray/core/dataarray.py

@@ -1418,7 +1418,7 @@ def gradient(self, scale_by_radius: bool = True, **kwargs) -> UxDataset:
         Parameters
         ----------
         scale_by_radius : bool, default=True
-            Scale derivatives by ``uxgrid.sphere_radius``.
+            Divide unit-sphere derivatives by ``uxgrid.sphere_radius``.
 
         Returns
         -------
@@ -1474,7 +1474,7 @@ def curl(
             represent the meridional (v) component, while self represents the
             zonal (u) component.
         scale_by_radius : bool, default=True
-            Scale derivatives by ``uxgrid.sphere_radius``.
+            Divide unit-sphere derivatives by ``uxgrid.sphere_radius``.
         **kwargs : dict
             Additional keyword arguments (currently unused, reserved for future extensions).