WAC. CLIMATE FILE EMPTY CELL WARNING

[tuba]

Hello,
I am using WUFI PLUS in my thesis. WAC. I prepared a climate file in format. At the station where I got the weather data, some hours were not measured. I entered those cells as empty, but when exporting, an "empty cell" warning appeared. What should I do with those empty cells?
Another question I have is: I chose the cloud index unit octas and entered data between 0 and 8. Isn't that true?
And my last question: the station from which I got the weather data only measures the global solar radiation data. I know that global radiation is the sum of diffuse and direct solar radiation. But how can I calculate any of the diffuse and direct solar radiation? Do you have any suggestions?
Best regards
Tuğba Yıldız
M.Sc. student at Istanbul Technical University, Turkey

[Thomas]

At the station where I got the weather data, some hours were not measured. I entered those cells as empty, but when exporting, an "empty cell" warning appeared. What should I do with those empty cells?

Hi Tuğba Yıldız

simulation programs always need complete data for the climatic conditions. So please fill the empty cells with plausible values. Small gaps (an hour or a few hours) can be filled by linear interpolation, large gaps (a significant fraction of a day or more) can be filled with a copy of one of the neighboring days.

Another question I have is: I chose the cloud index unit octas and entered data between 0 and 8. Isn't that true?

That is what many meteorological stations are using, but the cloud index in a WAC file is specified as the cloud fraction and has therefore values between 0 and 1. Please divide the octas by eight. (And look out for possible values of -1 or 9 octa which are used by some meteorological stations to mean "not observed" or something similar. I'm usually replacing these by a cloud index = 0.5).

And my last question: the station from which I got the weather data only measures the global solar radiation data. I know that global radiation is the sum of diffuse and direct solar radiation. But how can I calculate any of the diffuse and direct solar radiation? Do you have any suggestions?

If you are simulating a flat roof (that is, a horizontal surface), global radiation is sufficient. In all other cases, diffuse radiation is needed, too. If only global radiation has been measured, it is possible to estimate the diffuse component from the global radiation. For this, we are using the method devised by R.R.Perez, but this is a somewhat complex procedure. If it's only one single file, we can do that for you if you attach the file to a forum posting.

Best regards,
Thomas

[tuba]

Thank you very much for your answers. I have attached the file for the diffuse and direct solar radiation data. Do you think everything is ok with other data?
Thanks in advance for your help.
Best regards
Tuğba

[Thomas]

(done by email - Thomas)