Splitting actual ET into E & T

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duminda
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Joined: Wed Feb 14, 2018 8:34 pm
Location: Canada

Splitting actual ET into E & T

Post by duminda » Thu Feb 15, 2018 3:11 pm

Hi all:
I'm new to Hydrus. I would like to know your comments /suggestions about how to input parameters of ET.
I know that in Hydrus, we have to introduce potential evaporation and potential transpiration as inputs separately. however, I have actual estimated ET from an eddy covariance. I was wondering if the splitting into E & T is the only mean in Hydrus or is there any alternative way to solve this.
Thank you
Duminda

Jirka
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Location: USA
Location: Riverside, CA

Re: Splitting actual ET into E & T

Post by Jirka » Thu Feb 15, 2018 4:13 pm

You can either separate potential ET into potential E and potential T externally and then enter these values as input into HYDRUS, or you can enter potential ET directly and provide information about LAI so that HYDRUS knows how to separate it internally. You can select the latter option by checking the “Input PET and LAI” checkbox. J.

ahughes7
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Joined: Tue Dec 18, 2018 7:21 pm
Location: Canada

Re: Splitting actual ET into E & T

Post by ahughes7 » Sun Jul 28, 2019 9:06 pm

Hello,

I have the same question. I have measured actual ET from an eddy-covariance system and would like to know how to split this into Ep and Tp. I do not know the Kc or the LAI. Even if I was able to find LAI values in the literature, how do I obtain ETp for input into HYDRUS?

Cheers and thanks in advance,

Alexandra

Jirka
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Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Splitting actual ET into E & T

Post by Jirka » Mon Jul 29, 2019 9:24 pm

Potential ET is usually evaluated using models such as Penman-Monteith, Hargreaves, etc, from measured meteo data. See references given in the HYDRUS-1D manual: Monteith, 1981; Monteith and Unsworth, 1990; FAO, 1990; Hargreaves, 1994; and Jensen et al., 1997.

J.

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