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RE: which sort of time is influenced by time zone?

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which sort of time is influenced by time zone?
time zone
Answer (Unmark)
6/28/17 3:43 AM
Hi there,

Recently when I run a small model, I met an problem relating with time zone setting.

To illustrate my problems, I'm going to take a model with one river boundary upstream and one open sea boundary as an example. The time zone is set to 8.

At river boundary, set the time-series discharge data starts from 2016/11/09 17:00:00 and the model start time is 2016/11/10 00:00:00 ( time zone 8). When run model, the errors occur. Diagnose file suggests EC-module errors and I found the error occurs when interpolating time-series boundary conditions to model time steps.

Then we extend the discharge data one hour forward, say starting from 2016/11/09 16:00:00 (just 8 hrs before model start time), the model can run without error. So, it seems that the time specified in time-series boundary conditions doesnot refer to the time zone 8, but the UTC. Is it true?

To my experience from D3D, once the time zone specified in mdf, the times used in boundary conditions all refer to that. Only the metero data can have its own time zone. Obviously, DflowFM is not.

So, it turns out to another similar question: in Dflow FM, which times are influenced by time zone and which are not? I have looked up the manual. unfortunately it is not clear on this.

Thanks!

Peng
RE: which sort of time is influenced by time zone?
Answer (Unmark)
6/30/17 5:13 PMas a reply to peng yao.
Dear Peng,

First of all, your observation is correct that time zones in boundary conditions in DflowFM are treated differently from D3D.

This can be the case when the boundary time series are provided in the BC-format. In that format, the time-variable has a unit that is expressed as a UDUNIT-string, from which the time zone of the data is extracted. The difference in time zone between data and model is also taken into account by DflowFM. Please check the time zone in BC-file, which works similar to the time zone in netcdf-files for meteo.

Kind regards,
Jing Zhao

Deltares
RE: which sort of time is influenced by time zone?
Answer (Unmark)
7/2/17 11:50 AMas a reply to Jing Zhao.
Hi Jing,

Thanks very much for the reply.
Then I know how the bc-file works. Another little question is how to set a time zone in bc-file?
I attached an example of bc-file which is generated by DelftShell:
...................................................................
[forcing]
Name = rivbnd_0001
Function = timeseries
Time-interpolation = linear
Quantity = time
Unit = seconds since 2016-11-01 00:00:00
Quantity = dischargebnd
Unit = m³/s
723600 4920
727200 5000
730800 4520
734400 2060
738000 2520
741600 476
745200 -880
748800 -1380
......................

I didnot find a time zone setting here in the Unit row. Maybe I have to attach a string in Unit row manually, that is: Unit = seconds since 2016-11-01 00:00:00 +8:00:00, if I want to set "2016-11-01 00:00:00" to time zone 8. Am I right? Thanks!

Peng
RE: which sort of time is influenced by time zone?
Answer (Unmark)
7/3/17 3:50 PMas a reply to peng yao.
Dear Peng,

Your solution is correct.

Cheers,
Jing Zhao

Deltares