Merge pull request #1742 from MetOffice/1738_dialy_min_temperature_difference

Add spatial difference for min temperature

Author: daflack

src/CSET/cset_workflow/meta/diagnostics/rose-meta.conf

@@ -941,7 +941,20 @@ description=IMPACT-BASED DIAGNOSTIC.
 help=This diagnostic identifies the daily minimum temperature at each grid point.
 type=python_boolean
 compulsory=true
-sort-key=dw9
+sort-key=dw12
+
+[template variables=DAILY_09_MINIMUM_TEMPERATURE_SPATIAL_DIFFERENCE]
+ns=Diagnostics/Derived/Daily
+title=Daily minimum temperature: spatial difference
+description=IMPACT-BASED DIAGNOSTIC.
+            Determines the daily minimum temperature defined between 0900 UTC
+            and 0900 UTC the following day and takes the difference between
+            two models. Requires temperature_at_screen_level with cell_method
+            of minimum.
+help=This diangostic identifies the daily minimum temperature at each grid point.
+type=python_boolean
+compulsory=true
+sort-key=dw13
 
 ###################################
 # Aviation

src/CSET/cset_workflow/rose-suite.conf.example

@@ -21,6 +21,7 @@ CSET_MODEL_COUNT=1
 DAILY_09_MAXIMUM_TEMPERATURE_SPATIAL_PLOT=False
 DAILY_09_MAXIMUM_TEMPERATURE_SPATIAL_DIFFERENCE=False
 DAILY_09_MINIMUM_TEMPERATURE_SPATIAL_PLOT=False
+DAILY_09_MINIMUM_TEMPERATURE_SPATIAL_DIFFERENCE=False
 DETERMINISTIC_PLOT_CAPE_RATIO=False
 DETERMINISTIC_PLOT_INFLOW_PROPERTIES=False
 EXTRACT_MLEVEL_TRANSECT=False

src/CSET/loaders/spatial_difference_field.py

@@ -246,6 +246,24 @@ def load(conf: Config):
                 aggregation=False,
             )
 
+    # Daily minimum temperature.
+    if conf.DAILY_09_MINIMUM_TEMPERATURE_SPATIAL_DIFFERENCE:
+        base_model = models[0]
+        for model in models[1:]:
+            yield RawRecipe(
+                recipe="daily_09_minimum_temperature_spatial_difference.yaml",
+                variables={
+                    "BASE_MODEL": base_model["name"],
+                    "OTHER_MODEL": model["name"],
+                    "SUBAREA_TYPE": conf.SUBAREA_TYPE if conf.SELECT_SUBAREA else None,
+                    "SUBAREA_EXTENT": conf.SUBAREA_EXTENT
+                    if conf.SELECT_SUBAREA
+                    else None,
+                },
+                model_ids=[base_model["id"], model["id"]],
+                aggregation=False,
+            )
+
     # Create a list of case aggregation types.
     AGGREGATION_TYPES = ["lead_time", "hour_of_day", "validity_time", "all"]
 

src/CSET/recipes/derived_diagnostics/daily_weather/daily_09_minimum_temperature_spatial_difference.yaml

@@ -0,0 +1,44 @@
+category: Daily Weather
+title: "Daily minimum temperature at 0900 UTC\nDifference ($BASE_MODEL - $OTHER_MODEL)"
+description: |
+  Extracts and plots the daily minimum temperature between 0900 UTC and 0900 UTC
+  the following day as per observation measurements and plots the difference. The minimum
+  is created from a rolling 24 h window, adds hour of day coordinate, and then
+  selects the 21 UTC hour from the rolling window as this represents the validity
+  time of the required range. The minimum temperature can occur any time in the 24
+  h window.
+
+steps:
+  - operator: read.read_cubes
+    file_paths: $INPUT_PATHS
+    model_names: [$BASE_MODEL, $OTHER_MODEL]
+    constraint:
+      operator: constraints.combine_constraints
+      varname_constraint:
+        operator: constraints.generate_var_constraint
+        varname: 'temperature_at_screen_level'
+      cell_methods_constraint:
+        operator: constraints.generate_cell_methods_constraint
+        cell_methods: ['minimum']
+        coord: 'time'
+        interval: '1 hour'
+    subarea_type: $SUBAREA_TYPE
+    subarea_extent: $SUBAREA_EXTENT
+
+  - operator: aggregate.rolling_window_time_aggregation
+    method: 'MIN'
+    window: 24
+
+  - operator: misc.difference
+
+  - operator: aggregate.add_hour_coordinate
+
+  - operator: filters.filter_multiple_cubes
+    constraint:
+      operator: constraints.generate_hour_constraint
+      hour_start: 21
+
+  - operator: plot.spatial_pcolormesh_plot
+
+  - operator: write.write_cube_to_nc
+    overwrite: True