This webinar will cover a brief explanation of some simplified evaporation and evapotranspiration (ET) calculation methods, followed by the FAO method with a demonstration of 1 or more of these and show how they can be applied in a real application to calculate water demand. Methods likely included in this webinar:

Time series input

Seasonal adjustments using a lookup table

Harmon Evaporation Calculation

Hargreaves Samani ET

Reference ET (from FOA publications)

Below is a video recording of the webinar presentation:

Download the example models used for this presentation:

Thanks for commenting! I want to make sure I understand the meanings of some definitions. PET is potential evapotranspiration, or the amount of water that could in theory be removed due to ET, correct? And the Pan coefficient is what we use as a multiplier to convert evaporation measured in a pan to evaporation that occurs on the water surface of a lake, correct?

I still need to watch the video again to see if perhaps I created some confusion around those definitions. I'm curious to see what you think.

Thanks for your response. Yes, that is correct. In this video on 22mm 48ss, I noted that you transformed ET into PET with a Pan coefficient. Nth is major. I just want to confirm this. Many thanks

## Comments

4 comments

Hi Jason,

One quick question, what is the equation you use to transform evaporatration into PET? I am thinking just to multiply by Pan coefficient?

Thanks for commenting! I want to make sure I understand the meanings of some definitions. PET is potential evapotranspiration, or the amount of water that could in theory be removed due to ET, correct? And the Pan coefficient is what we use as a multiplier to convert evaporation measured in a pan to evaporation that occurs on the water surface of a lake, correct?

I still need to watch the video again to see if perhaps I created some confusion around those definitions. I'm curious to see what you think.

Hi Jason,

Thanks for your response. Yes, that is correct. In this video on 22mm 48ss, I noted that you transformed ET into PET with a Pan coefficient. Nth is major. I just want to confirm this. Many thanks

I watched that part and remembered what I did there.

PET = Evapotranspiration / Pan_Coefficient

PET stands for "pan evapotranspiration", which is often what we might find in a time series record of measured data.

I can't remember how I obtained the Pan_Coefficient, though.

Does this help?

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