Community Support
Hello Pierre,
I have a feature request: could you include Penman-Monteith evapotranspiration under the derived (calculated) data? Currently I'm using an Excel sheet where I manually enter the observations of my Weatherflow station to calculate PM evapotranspiration. I use it to estimate irrigation requirements for my orange trees. It would be wonderful if Weather Station could do the calculations for me 🙂
The calculation is a bit complex and is described at https://en.wikipedia.org/wiki/Penman%E2%80%93Monteith_equation and http://www.fao.org/3/X0490E/x0490e06.htm. There is a step-by-step recipe described in https://edis.ifas.ufl.edu/pdffiles/AE/AE45900.pdf (that's the one I'm using in my Excel sheet).
BTW, I saw that evapotranspiration is already mentioned in the handbook, am I correct that it needs a soil sensor?
Kind regards,
Ruud.
Hello Ruud!
Wow that's a fucking equation... and a nice idea 😉 I will see if I can add it to my backlog during my holidays (not a promise, but I will try).
For the current evapotranspiration, you're unfortunately right, you need a soil sensor, sorry...
If you like Weather Station, please consider to make a review to help make it known. That would be the best way to thank me...
Hello Pierre,
Thanks for your immediate and positive reply 🙂 The guys at University of Florida (third link) broke the formula down into a series of steps that make it a lot easier to implement in code (or Excel sheets). I'm happy to share my sheet, by the way.
Of course I understand that you can't make any promises (and holidays are usually better spent at other places than sitting behind a screen). Thanks for making such a wonderful plug-in!
Kind regards,
Ruud.
Hi there and excuse me for the intromission. A short approach for Evapotranspiration is to use Hargreaves-Samani ET computation, that's a lot more simplified that uses mean air temperature and solar radiation (if you don't have a solar radiometer, you can compute from max and min temperature + use Solar constant for your latitude).
But I know that Penman-Monteith is the "holy grial" for agronomical sciences, and the best ET estimate.
Best regards.
David.
David Aguilera-Riquelme (@davidagriq).
https://redmeteo.cl - an Open Chilean hobbyist weather network