1) Hardware calculation I'm now curious if this price range system is providing ET. As the owner of this system, I leave that to you to investigate further and let us know. Is there reference in the system manual, website, display, or other?
2) ET - EvapoTranspiration ET is defined as the amount of evaporation that would occur if a sufficient water source were available. That is, EvapoTranspiration is considered the net result of atmospheric demand for moisture from a surface and the ability of the surface to supply moisture. Surface, air temperatures, insolation, humidity and wind all affect ET. A dryland is a place where annual potential evaporation exceeds annual precipitation (ie, ET is "an inverse" of rain). - Davis Instruments derived weather variables (PDF): https://www.davisinstruments.com/product_documents/weather/app_notes/AN_28-derived-weather-variables.pdf - Step by Step Calculation of the Penman-Monteith Evapotranspiration; Lincoln Zotarelli et others, University of Florida [2018]: https://edis.ifas.ufl.edu/ae459 - Guidelines for computing crop water requirements - FAO Irrigation and drainage; FAO - Food and Agriculture Organization of the United Nations [1998]: http://www.fao.org/3/x0490e/x0490e00.htm As a "newer" weather derived variable, for most of us ("weather enthusiasts") still a curiosity, but getting much traction as it continues to be further adopted to hardware and software. Most indeed, for those in irrigation, drainage and agriculture. As "reverse rain", to note that the units of measurement in "mm/in". X -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/6979e1f8-92dc-454e-9294-5c688454f959%40googlegroups.com.
