Dear all, 

I am trying to compute Evapotranspiration (Eto)

According to instructions it is that the three components of the total ETo are as follows:

- variable "Evaporation from bare soil" ,
- variable "Evaporation from open water surfaces excluding oceans,
- variable "Evaporation from vegetation transpiration",

So, to compute ETo I am adding the 3 components. 

I have a mix of negative and positive values, and I thought ETo should be 0 - 1 

Am I missing something

Would appreciate a reply asap

Many Thanks for the attention

Kind Regards

Joana