Add fix for iris longitude bug to ClimWIP

esmvaltool/diag_scripts/weighting/weighted_temperature_map.py

@@ -11,15 +11,12 @@
 import matplotlib.pyplot as plt
 import numpy as np
 from cartopy.mpl.ticker import LatitudeFormatter, LongitudeFormatter
-from climwip.io_functions import (
-    log_provenance,
-    read_model_data,
-)
+from climwip.io_functions import log_provenance, read_model_data
 
 from esmvaltool.diag_scripts.shared import (
-    run_diagnostic,
-    get_plot_filename,
     get_diagnostic_filename,
+    get_plot_filename,
+    run_diagnostic,
 )
 from esmvaltool.diag_scripts.weighting.plot_utilities import (
     calculate_percentiles,
@@ -30,6 +27,37 @@
 logger = logging.getLogger(os.path.basename(__file__))
 
 
+def set_antimeridian(dataarray, to: str):
+    """Flip the antimeridian (i.e. longitude discontinuity) between Europe
+    (i.e., [0, 360)) and the Pacific (i.e., [-180, 180)).
+
+    Parameters
+    ----------
+    - dataarray : xarray.DataArray
+    - to : string, {'pacific', 'europe'}
+      * 'europe': Longitude will be in [0, 360)
+      * 'pacific': Longitude will be in [-180, 180)
+
+    Returns
+    -------
+    dataarray : xarray.DataArray
+    """
+    lon = dataarray['lon']
+
+    if to.lower() == 'europe':
+        dataarray = dataarray.assign_coords(lon=lon % 360)
+    elif to.lower() == 'pacific':
+        dataarray = dataarray.assign_coords(lon=((lon + 180) % 360) - 180)
+    else:
+        errmsg = "to has to be one of ['europe', 'pacific'] not {}".format(to)
+        raise ValueError(errmsg)
+
+    idx = np.argmin(dataarray['lon'].values)
+    dataarray = dataarray.roll(lon=-idx, roll_coords=True)
+    dataarray['lon'].attrs = lon.attrs
+    return dataarray
+
+
 def mapplot(dataarray, cfg, title_pattern, filename_part, ancestors,
             **colormesh_args):
     """Visualize weighted temperature."""
@@ -44,6 +72,9 @@ def mapplot(dataarray, cfg, title_pattern, filename_part, ancestors,
     proj = ccrs.PlateCarree(central_longitude=0)
     figure, axes = plt.subplots(subplot_kw={'projection': proj})
 
+    dataarray = set_antimeridian(dataarray, cfg.get('antimeridian', 'pacific'))
+    dataarray = dataarray.dropna('lon', how='all').dropna('lat', how='all')
+
     dataarray.plot.pcolormesh(
         ax=axes,
         transform=ccrs.PlateCarree(),
@@ -104,7 +135,7 @@ def visualize_and_save_difference(temperature_difference, cfg: dict,
                                   ancestors: list):
     """Wrap mapplot: temperature difference between weighted and unweighted."""
     title_pattern = '\n'.join([
-        'Difference: weighted minus unweighted {metric} temperature',
+        'Weighted minus unweighted {metric} temperature',
         r'{period} ($\degree$C)',
     ])
     filename_part = 'temperature_change_difference_map'

esmvaltool/recipes/recipe_climwip_test_basic.yml

@@ -42,7 +42,7 @@ preprocessors:
     mask_landsea:
       mask_out: sea
     extract_region:
-      start_longitude: 0.0
+      start_longitude: -10.0
       end_longitude: 39.0
       start_latitude: 30.0
       end_latitude: 76.25
@@ -134,5 +134,5 @@ diagnostics:
         weights: 'weights.nc'
         # optional arguments
         model_aggregation: mean  # [ mean (default) | median | integer in (0, 100) ]
-        xticks: [0, 10, 20, 30, 40]  # if not given ticks will be set automatically
+        xticks: [-10, 0, 10, 20, 30, 40]  # if not given ticks will be set automatically
         yticks: [30, 40, 50, 60, 70, 80]