Diag_manager_mod documentation PR

[mp586]

Documentation for diag_manager_mod focusing mostly on how to save Isca output ( at different frequencies ) and including a list of standard diagnostic variables.

[rosscastle]

Hi Marianne, sorry this took me so long to get round to! I think this is really great, there's not much I can think to improve really. A few very minor stylistic points:

• I think it could be made a bit clearer how often you can output all the data on multiple timescales (e.g. all data hourly, daily, monthly) for 1 run. I think it would help if you explain what each of the 'module, name, time_avg, files' are - importantly make it clear that 'files' refers to the 'atmos_monthly' etc. Also you could make it clear that you only need 1. In the second sentence of the second paragraph I think it would make more sense if you started with 'If you only wanted specific variables saved on at a particular output frequency(cies), then you can...'
• I think it would look a little neater if in the text the namelist options (e.g. true/false/none/123) were also formatted. E.g. line 81: ' If files = None ' could be ' If files = None '.
• In the output field table, the unit for relative humidity has a \ (slash) in it.
• Line 57, I think it would be helpful (although hopefully obvious) to point out that examples of a diag script are in those example runscripts near the top.

[rosscastle]

RC's changes made with MPs permission.