WW3 History Output

[anton-seaice]

There are a few limitations in the WW3 output we will need to look into at some point:

• There is no time_bounds or time_period information with the output, so there is no record of what time average (except nuopc.runconfig) has been applied to the data. (i.e. is it daily/monthly or something else).
• History output can only be saved at one time frequency (i.e. we can't have both monthly and daily in the same experiment).
• The output is timestamped at the end of the time interval, which makes it appear like its the next day (i.e. 1900-01-01 is timestamped as '1900-01-02T00:00:00.000000000'

[anton-seaice]

[anton-seaice]

We will resolve this through #152