Add support for fx.zfull

src/access_moppy/derivations/__init__.py

@@ -7,6 +7,8 @@
     cl_level_to_height,
     cli_level_to_height,
     clw_level_to_height,
+    level_to_height,
+    load_zfull_resource,
 )
 from access_moppy.derivations.calc_land import (
     calc_carbon_pool_kg_m2,
@@ -65,7 +67,9 @@
     "cli_level_to_height": cli_level_to_height,
     "clw_level_to_height": clw_level_to_height,
     "cl_level_to_height": cl_level_to_height,
+    "level_to_height": level_to_height,
     "calculate_areacella": calculate_areacella,
+    "load_zfull_resource": load_zfull_resource,
     "isel": lambda x, **kwargs: x.isel(**kwargs),
     "calc_topsoil": calc_topsoil,
     "calc_landcover": calc_landcover,

src/access_moppy/derivations/calc_atmos.py

@@ -34,6 +34,8 @@
 
 # import click
 # import dask
+from importlib.resources import as_file, files
+
 import numpy as np
 import xarray as xr
 
@@ -178,6 +180,35 @@
 # ----------------------------------------------------------------------
 
 
+def level_to_height(ds):
+    """
+    Transform model level indices to height coordinates.
+
+    Converts from level dimension to height dimension by using stored height values
+    and updating dimension coordinates accordingly.
+
+    Parameters
+    ----------
+    ds : xarray.Dataset
+        Dataset with model level coordinates
+
+    Returns
+    -------
+    xarray.Dataset
+        Dataset with height coordinate dimension
+    """
+    # Handle level coordinate transformation
+    if "theta_level_height" in ds:
+        ds = (
+            ds.assign_coords({"lev": ds["theta_level_height"]})
+            .swap_dims({"model_theta_level_number": "lev"})
+            .drop_vars(
+                ["theta_level_height", "model_theta_level_number"], errors="ignore"
+            )
+        )
+    return ds
+
+
 def cli_level_to_height(ds):
     # Handle level coordinate transformation
     if "theta_level_height" in ds:
@@ -306,3 +337,31 @@ def calculate_areacella(nlat=145, nlon=192, earth_radius=6371000.0):
 
     # Return as Dataset for use in internal calculations
     return xr.Dataset({"areacella": areacella_2d})
+
+
+def load_zfull_resource():
+    """
+    Load zfull height coordinate from package resource file.
+
+    This function loads pre-computed height values for model levels that are
+    shipped with the package and applies the level_to_height transformation.
+    No model input is required.
+
+    Returns
+    -------
+    xarray.Dataset
+        Dataset containing zfull coordinate with dimensions (alevel, lat, lon)
+
+    Notes
+    -----
+    The resource file is typically named fx.zfull_ACCESS-ESM.nc and contains
+    height values above reference ellipsoid for each atmospheric model level.
+    The operation applies level-to-height coordinate transformation.
+    """
+    resource_file = files("access_moppy.ressources") / "fx.zfull_ACCESS-ESM.nc"
+    with as_file(resource_file) as path:
+        ds = xr.open_dataset(path)
+
+    # Apply level_to_height transformation
+    ds = level_to_height(ds)
+    return ds

src/access_moppy/mappings/ACCESS-ESM1.6_mappings.json

@@ -1532,6 +1532,21 @@
                 "type": "direct",
                 "formula": "fld_s05i206"
             }
+        },
+        "zfull": {
+            "dimensions": {
+                "alevel": "model_theta_level_number",
+                "lat": "lat",
+                "lon": "lon"
+            },
+            "units": "m",
+            "positive": null,
+            "model_variables": "fld_s15i101",
+            "calculation": {
+                "type": "internal",
+                "function": "load_zfull_resource"
+            },
+            "CF standard Name": "height_above_reference_ellipsoid"
         }
     },
     "land": {