Added new example recipe to demonstrate the use of variable groups

Author: schlunma

esmvaltool/recipes/examples/recipe_concatenate_exps.yml

@@ -1,4 +1,17 @@
+# recipe_concatenate_exps.yml
 ---
+documentation:
+
+  description: |
+    Example recipe to demonstrate concatenation of different experiments.
+
+  authors:
+    - schl_ma
+
+  projects:
+    - crescendo
+
+
 datasets:
   - {dataset: CanESM2}
   - {dataset: GFDL-ESM2M}

esmvaltool/recipes/examples/recipe_variable_groups.yml

@@ -0,0 +1,61 @@
+# recipe_variable_groups.yml
+---
+documentation:
+
+  description: |
+    Example recipe to demonstrate grouping of variables in the diagnostic
+    section.
+
+  authors:
+    - schl_ma
+
+  projects:
+    - crescendo
+
+
+preprocessors:
+
+  mask:
+    mask_landsea:
+      mask_out: sea
+
+
+ARBITRARY_YAML_ANCHOR: &datasets
+  - {dataset: CanESM2}
+  - {dataset: IPSL-CM5A-LR}
+  - {dataset: MIROC5}
+  - {dataset: MPI-ESM-LR}
+  - {dataset: NorESM1-M}
+
+
+diagnostics:
+
+  diag_variable_groups:
+    description: Demonstrate the use of variable groups.
+    variables:
+      tas_1: &variable_settings
+        short_name: tas
+        project: CMIP5
+        mip: Amon
+        field: T2Ms
+        exp: historical
+        ensemble: r1i1p1
+        start_year: 2000
+        end_year: 2005
+        tag: TAS1
+        additional_datasets: *datasets
+      tas_2:
+        <<: *variable_settings
+        preprocessor: mask
+        tag: TAS2
+        additional_datasets:
+          - {dataset: ERA-Interim, project: OBS, type: reanaly, version: 1, tier: 3}
+      tas_3:
+        <<: *variable_settings
+        exp: rcp45
+        start_year: 2020
+        end_year: 2025
+        tag: TAS3
+        additional_datasets: *datasets
+    scripts:
+      null