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Hi

I have implemented time varying pressure in Telemac2D (v8p0r2), and is working fine. I see small changes in the free surface compared to tide only runs.

But could some please clarify the units of atmospheric pressure.

In the manual (v8p0) the keyword AIR PRESSURE has a default value of 10,000 Pa. Whereas, in the T2D example waq2d_thermic, the meteo file has values of 1000 mbar. Again, when using the scripts convert_ECMWF.py the values of pressure in the binary meteorological files are on the order of 10,000 Pa.

So which is the correct unit? or is it specific depending on the wind file option 2 or 3 etc?

Many thanks

David

Hello David,

The correct unit for atmospheric pressure is Pa.

Nevertheless, if coupling with WAQTEL or WIND = YES, and also use ASCII ATMOSPHERIC DATA FILE at the same time, the expected unit for pressure in the ASCII ATMOSPHERIC DATA FILE is mbar (= hPa) as you wrote.
For the latter, the choice was done because meteo data for pressure are often given with this format.

Hope this helps,

Chi-Tuan

Thank you Chi-Tuan, that's much clearer.

David

Hi Chi-Tuan,
is this rule valid also for a binary atmospheric data file?
Should I define the atmospheric pressure in hPa in my selafin file?
Thank you.
Kind regards,
Francesco

Hello Francesco,

Which release do you use?
For what purpose? Water quality/thermic modelling? Storm surge?

If using a release up to release v8p5r1, if you want to use an atmospheric data file, pressure has to be given in hPa. If you want to use for storm surge modelling (and no thermic module), pressure has to be given in Pa.
If you want to model both, there are inconsistencies.

From release 9.0 (coming very soon...) you will have a new keyword PRESSURE UNIT to decide in which unit is defined pressure (default = Pa).

Hope this helps,

Chi-Tuan

Hi Chi-Tuan,
thank you for your reply. It's all clear.
I am currently using the release v8p4r0.
I am modelling a storm surge with no thermic model, so there is no risk of inconsistencies.
Kind regards,
Francesco