Hi all,

two very common things that users will want to do in ESMValTool are:

1. Compare single model ensemble means.
   For instance, I have a HadGEM2-ES 4 member ensemble and UKESM 12 member ensemble. I want to make some time series plots showing the time development of the two single-model ensemble means.
   How do I do that? Is there a way to use the multi_model_statistics preprocessor so that it only compares single models? Or perhaps we need a single_model_ensemble_statistics preprocessor?

2. Calculate the differences between two specific time periods in the preprocessor stage.
   For instance, I want to look at average surface temperature in the years 1975-2000 minus the average surface temperature between 1875-1900.
   I don't know of a way to do this in the preprocessor, it seems to be such a common job that it would be great to get it as a preprocessor instead of in the diagnostic stage.

Any ideas?

Lee