User documentation

Author: NParsonsMO

doc/source/user_guide/esmvaltool_branches.rst

@@ -0,0 +1,23 @@
+.. (C) Crown Copyright 2026, Met Office.
+.. The LICENSE.md file contains full licensing details.
+
+Using a branch of ESMValTool
+============================
+
+.. include:: ../common.txt
+
+
+Branches
+--------
+
+By default, |CMEW| will use a released version of ESMValTool such as v.2.13.0.
+
+There may be circumstances where it is desirable instead to use a different branch, for example,
+a CMEW user may have their own recipes and diagnostic scripts available in a branch of ESMValTool,
+or they may wish to use a new diagnostic which is in main but not yet in a release.
+
+This functionality is controlled by two variables in the `rose-suite.conf` file.
+e.g. to use the branch "main" one would set the following::
+
+    USE_ESMVALTOOL_BRANCH=true
+    ESMVALTOOL_BRANCH="main"

doc/source/user_guide/index.rst

@@ -12,4 +12,5 @@ User Guide
    quick_start
    workflow
    Configuring datasets <configuring_datasets>
-   Reusing raw data  <reusing_raw_data>
+   Reusing raw data <reusing_raw_data>
+   ESMValTool branches <esmvaltool_branches.rst>