Theoretical background on pwsFWI: Difference between revisions

The whole process of evaporation and drying is implicit. I will not try to quantify the waterbalance exactly which would result in a quantification of the [[Charts_-_Misc_charts#Daily_EVT_.28Evapotranspiration.29|Evapotranspiration]]. Evaporation is an extremely complex process, Seetoo much for this wiki page, see some pages on the wikiwikipedia <ref>[https://en.wikipedia.org/wiki/Evaporation Evaporation], [https://en.wikipedia.org/wiki/Hydrology_(agriculture) Hydrology (agriculture)] and the [http://www.fao.org/3/X0490E/x0490e00.htm FAO Irrigation and drainage paper 56].</ref>, which is far beyond the scope of a fire weather index. EvenBut even for professionals it is a complex professionallyphenomenon, as it is influenced by vegetation, crop, soil etc… In short, the whole environment. That would be a bit too much although I think in principle it can be done.

So, relative humidity (fraction), wind (in km/h) and temperature (in °C) are the measurements used for the daily calculation as shown above. Furthermore the effect of the duration of dry and (possibly windy) weather needs to be taken into account and that is done through a process of testing and adjusting (a kind of calibration) until the output delivers consistent warning levels comparable with experience and existing fire weather indices.