Optimal metadata for a daytime maximum

[gavinevans]

As a developers, we need to have a clear way of recording that the contents of a file is a "daytime maximum", so that this can be differentiated from other files.

For calculating a daytime maximum screen temperature, it is necessary to take files over a period e.g. 09Z to 21Z and calculate the maximum. Currently the only knowledge that a daytime maximum has been calculated is within the filename, for example:

temperature_at_screen_level_daytime_max / (K) (time: 1; percentile: 1; index: 121)
     Dimension coordinates:
          time                                     x              -         -
          percentile                               -              x         -
          index                                    -              -         x
     Auxiliary coordinates:
          forecast_period                          x              -         -
          altitude                                 -              -         x
          latitude                                 -              -         x
          longitude                                -              -         x
     Scalar coordinates:
          forecast_reference_time: 2017-10-13 04:00:00
          height: 1.5 m
     Cell methods:
          weighted_mean: model

The fact that a maximum has been calculated is typically recorded in the cell method. However, it is not clear how to specify the time period over which the maximum has been calculated.