Output time stamps

[dprincz]

@o-sha:
I am comparing some hourly output with observed data. When MESH has hourly output, for example 2022-01-01 2:00 AM, is this output at the end of the 2 AM hour (just before 3 AM), or at beginning of the 2 AM hour?

MESH hours run from 00:00 to 23:00. After 23:00 has elapsed, it resets to 00:00 and the day is incremented by +1. A frame marked 02:00 (2 AM) contains values calculated in the time-step starting after 02:00 and ending before 03:00.

This can be in contrast to some forcing and/or analysis datasets, particularly those that count "hours into the future" as opposed to incremental days. It's done by design to be able to easily mask all hours corresponding to a particular day, where if it ran from 01:00 to 24:00, most interpreters would mark the frame 24:00 as belonging to the next date (e.g., 00:00 of day+1) and the time-series of sub-daily records corresponding to a run would appear to start with a day of 23 hours and end with a day of only 1 hour.

[dprincz]

Important

MESH has no awareness of seasonal time shifts (e.g., daylight savings) or time zones. Care might have to be taken when comparing simulated outputs to observations that haven't been converted to standard time.