Repository: ESMValGroup/ESMValCore

Issue:
New custom variable for tos uncertainty
For updating the ESACCI-SST dataset I would like to add the sea surface temperature uncertainty (tosStderr) as custom variable. 


Discussion:
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All modified and coverable lines are covered by tests :white_check_mark:
> Project coverage is 94.62%. Comparing base [(`d472381`)](https://app.codecov.io/gh/ESMValGroup/ESMValCore/commit/d472381e30a101ada18b617baca082abbaeb7d21?dropdown=coverage&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ESMValGroup) to head [(`cdf9fbc`)](https://app.codecov.io/gh/ESMValGroup/ESMValCore/commit/cdf9fbc26b4f6f18b03df53d2476cebc180c1158?dropdown=coverage&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ESMValGroup).

<details><summary>Additional details and impacted files</summary>


```diff
@@           Coverage Diff           @@
##             main    #2470   +/-   ##
=======================================
  Coverage   94.62%   94.62%           
=======================================
  Files         247      247           
  Lines       14055    14055           
=======================================
  Hits        13299    13299           
  Misses        756      756           
```

</details>

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Patch:
diff --git a/esmvalcore/cmor/tables/custom/CMOR_tosStderr.dat b/esmvalcore/cmor/tables/custom/CMOR_tosStderr.dat
new file mode 100644
index 000000000..31756d4cd
--- /dev/null
+++ b/esmvalcore/cmor/tables/custom/CMOR_tosStderr.dat
@@ -0,0 +1,26 @@
+SOURCE: CMIP5
+!============
+variable_entry:    tosStderr
+!============
+modeling_realm:    ocean
+!----------------------------------
+! Variable attributes:
+!----------------------------------
+standard_name:
+units:             K
+cell_methods:      time: mean
+cell_measures:     area: areacello
+long_name:         Sea Surface Temperature Error
+comment:           
+!----------------------------------
+! Additional variable information:
+!----------------------------------
+dimensions:        longitude latitude time
+out_name:          tosStderr
+type:              real
+valid_min:         0
+valid_max:
+ok_min_mean_abs:   0
+ok_max_mean_abs:
+!----------------------------------
+!


Test patch:
diff --git a/tests/integration/cmor/test_table.py b/tests/integration/cmor/test_table.py
index 385869bc5..680e5b4c0 100644
--- a/tests/integration/cmor/test_table.py
+++ b/tests/integration/cmor/test_table.py
@@ -477,7 +477,7 @@ class TestCustomInfo(unittest.TestCase):
         self.assertEqual(var.units, 'K')
 
     def test_get_variable_ch4s(self):
-        """Get tas variable."""
+        """Get ch4s variable."""
         CustomInfo()
         var = self.variables_info.get_variable('Amon', 'ch4s')
         self.assertEqual(var.short_name, 'ch4s')
@@ -485,6 +485,15 @@ class TestCustomInfo(unittest.TestCase):
                          'Atmosphere CH4 surface')
         self.assertEqual(var.units, '1e-09')
 
+    def test_get_variable_tosStderr(self):
+        """Get tosStderr variable."""
+        CustomInfo()
+        var = self.variables_info.get_variable('Omon', 'tosStderr')
+        self.assertEqual(var.short_name, 'tosStderr')
+        self.assertEqual(var.long_name,
+                         'Sea Surface Temperature Error')
+        self.assertEqual(var.units, 'K')
+
 
 @pytest.mark.parametrize(
     'project,mip,short_name,frequency',