cumulative integrate

test/test_cross_sections.py

@@ -226,3 +226,27 @@ def test_cross_section(gridpath, datasetpath):
         _ = uxds['RELHUM'].cross_section(start=(45, 45))
         _ = uxds['RELHUM'].cross_section(lon=45, end=(45, 45))
         _ = uxds['RELHUM'].cross_section()
+
+
+def test_cross_section_cumulative_integrate(gridpath, datasetpath):
+    uxds = ux.open_dataset(gridpath("scrip", "ne30pg2", "grid.nc"), datasetpath("scrip", "ne30pg2", "data.nc"))
+    cs = uxds['RELHUM'].cross_section(start=(-45, -45), end=(45, 45), steps=6)
+    cs = cs.assign_coords(distance=("steps", np.linspace(0.0, 1.0, cs.sizes["steps"])))
+
+    cs_ux = ux.UxDataArray(cs, uxgrid=uxds.uxgrid)
+
+    result = cs_ux.cumulative_integrate(coord="distance")
+    expected = cs.cumulative_integrate(coord="distance")
+
+    assert isinstance(result, ux.UxDataArray)
+    assert result.uxgrid == cs_ux.uxgrid
+    xr.testing.assert_allclose(result.to_xarray(), expected)
+
+
+def test_cumulative_integrate_requires_coord(gridpath, datasetpath):
+    uxds = ux.open_dataset(gridpath("scrip", "ne30pg2", "grid.nc"), datasetpath("scrip", "ne30pg2", "data.nc"))
+    cs = uxds['RELHUM'].cross_section(start=(-45, -45), end=(45, 45), steps=3)
+    cs_ux = ux.UxDataArray(cs, uxgrid=uxds.uxgrid)
+
+    with pytest.raises(ValueError, match="Coordinate .* must be specified"):
+        cs_ux.cumulative_integrate()

uxarray/core/dataarray.py

@@ -2,7 +2,7 @@
 
 import warnings
 from html import escape
-from typing import TYPE_CHECKING, Any, Hashable, Literal, Mapping, Optional
+from typing import TYPE_CHECKING, Any, Hashable, Literal, Mapping, Optional, Sequence
 from warnings import warn
 
 import numpy as np
@@ -513,6 +513,40 @@ def integrate(
 
         return uxda
 
+    def cumulative_integrate(
+        self,
+        coord: Hashable | Sequence[Hashable] | None = None,
+        datetime_unit: Optional[str] = None,
+    ) -> "UxDataArray":
+        """
+        Integrate cumulatively along the given coordinate using the trapezoidal rule.
+
+        Mirrors :py:meth:`xarray.DataArray.cumulative_integrate` while preserving
+        ``uxgrid`` on the result.
+
+        Parameters
+        ----------
+        coord : Hashable or sequence of Hashable
+            Coordinate(s) used for the integration. This must be provided.
+        datetime_unit : str, optional
+            Unit to use when integrating over datetime coordinates.
+
+        Returns
+        -------
+        UxDataArray
+            The cumulative integral along the specified coordinate.
+        """
+        if coord is None:
+            raise ValueError(
+                "Coordinate ('coord') must be specified for cumulative_integrate."
+            )
+
+        integrated = super().cumulative_integrate(
+            coord=coord, datetime_unit=datetime_unit
+        )
+
+        return UxDataArray(integrated, uxgrid=self.uxgrid)
+
     def zonal_mean(self, lat=(-90, 90, 10), conservative: bool = False, **kwargs):
         """Compute non-conservative or conservative averages of a face-centered variable along lines of constant latitude or latitude bands.