Introduction of Turbulence Index

improver/api/__init__.py

@@ -120,6 +120,7 @@
     "TemporalInterpolation": "improver.utilities.temporal_interpolation",
     "Threshold": "improver.threshold",
     "TriangularWeightedBlendAcrossAdjacentPoints": "improver.blending.blend_across_adjacent_points",
+    "TurbulenceIndexAbove1500m_USAF": "improver.turbulence",
     "VerticalUpdraught": "improver.wind_calculations.vertical_updraught",
     "VirtualTemperature": "improver.temperature.virtual_temperature",
     "VisibilityCombineCloudBase": "improver.visibility.visibility_combine_cloud_base",

improver/cli/turbulence_index_above_1500m_usaf.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+# (C) Crown Copyright, Met Office. All rights reserved.
+#
+# This file is part of 'IMPROVER' and is released under the BSD 3-Clause license.
+# See LICENSE in the root of the repository for full licensing details.
+"""Script to create Turbulence Indices above 1500 meters from multi-parameter datasets."""
+
+from improver import cli
+
+
+@cli.clizefy
+@cli.with_output
+def process(*cubes: cli.inputcube, model_id_attr: str = None):
+    """
+    From the supplied set of cubes at two, presumable adjacent, pressure levels, calculate the
+    Turbulence Index above 1500 m based on Ellrod 1997.
+    Values are typically small on the order of 1e-7 and are in units of 1/second^2 (i.e., s-2).
+    The returned Cube will have a long name beginning with "TurbulenceIndexAbove1500m" and
+    concatenated with a string representing the pressure level of the calculations in millibars.
+        E.g., name="TurbulenceIndexAbove1500m550mb"
+    The calculations are performed on the greater pressure level (lowest altitude) provided.
+
+    Args:
+        cubes (list of iris.cube.Cube):
+            Cubes to be processed.
+        model_id_attr (str):
+            Name of the attribute used to identify the source model for
+            blending.
+
+    Returns:
+        iris.cube.Cube:
+            Cube of Turbulence Index calculated at greatest provided pressure level in units of 1/second^2.
+    """
+    from iris.cube import CubeList
+
+    from improver.turbulence import TurbulenceIndexAbove1500m_USAF
+
+    result = TurbulenceIndexAbove1500m_USAF()(CubeList(cubes), model_id_attr=model_id_attr)
+
+    return result