open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello all,
I am trying to couple waqtel with the T3D model.

Same as the example heat exchange model we need to have hourly Nebulocity.
I tried to download historical data from Environment Canada website. But not sure which parameter needs to be looked at as Nebulacity. In the downloaded data the WEATHER column shows N/A.
So my questions are :
1- which parameter I should look at?
2- What do you suggest in case of unavailability of Nebulacity.
3- Nebulocity value should be a number from 0 to 9? and O corresponds to clear and 9 corresponds to Highly cloudy weather?


Thanks in advance,
SANAZ

Hello Sanaz,

2: if you do not have nebulosity data, you can still use ATMOSPHERE-WATER EXCHANGE MODEL = 1 (i.e. the linearised formula at the free surface) which only needs wind velocity and air temperature contrary to the model with complete balance = 2).
A bug was recently raised by IMDC in the calcs3d_thermics subroutine for this linearised formula with missing brackets:
A=(4.48D0+0.049D0*TREEL)+2021.5D0*C_ATMOS*(1.D0+WW)*
& (1.12D0+0.018D0*TREEL+0.00158D0*TREEL**2)/LAMB
should be replaced by:
A=(4.48D0+0.049D0*TREEL+2021.5D0*C_ATMOS*(1.D0+WW)*
& (1.12D0+0.018D0*TREEL+0.00158D0*TREEL**2))/LAMB
It was fixed in the trunk in r13473.

3: expected nebulosity/cloud cover by TELEMAC-3D using WAQTEL and the 1 or 2 option for ATMOSPHERE-WATER EXCHANGE MODEL should be in octas (between 0 and 8).
If you can read French, I can suggest you to read www.meteofrance.fr/publications/glossaire/152825-nebulosite
or en.wikipedia.org/wiki/Okta is OK.

Hope this helps,

Chi-Tuan

Thank you so much.It was very comprehensive.

Hello dear Chi-Tuan,
I was able to launch the simulation coupling with waqtel. However it seems the free surface temperature stays equal to the air temperature we specified as 15c.
Please have a look at our meta data.
I added below keywords in telemac cas file:
/************************************
/ WATER QUALITY
/************************************
COUPLING WITH = 'WAQTEL'
WAQTEL STEERING FILE = 'waq_steer.cas'
WATER QUALITY PROCESS = 11
RAIN OR EVAPORATION = no
WIND = YES
COEFFICIENT OF WIND INFLUENCE VARYING WITH WIND SPEED = YES

Please have a look at the graph attached. The green line shows temperature at the surface over time (1 day simulation).and red line is the bottom layer temperature.


I am just wondering if the solar radiation is taking into account.
I should mention that as I did not have hourly temperature file I put constant value of 15c. Surface temperature should change day vs night. Do you think that causes this constant temperature at the surface layer?

Thanks in advance,
Sanaz

Dear Sanaz,

No, radiation is not take into account with:
ATMOSPHERE-WATER EXCHANGE MODEL= 1

You must use 2.

You can try, but if you have dry zones, option 2 is not robust (in versions < v8p0).

Best regards
J

Thanks a mil.
Sanaz