Cosine function for variation of precipitation

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ghassemi
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Joined: Fri May 17, 2019 3:21 pm
Location: Canada

Cosine function for variation of precipitation

Post by ghassemi » Wed Jun 12, 2019 9:08 pm

Hello,

Variations in potential evaporation and transpiration during the day can be generated with HYDRUS-1D using a sinusoidal shape function proposed by
Fayer (2000). Similarly, variation of precipitation can also be approximated in HYDRUS-1D using a cosine function.
I appreciate if anyone could help me to find the original reference for the cosine function.

Thank you,
Ali

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

Re: Cosine function for variation of precipitation

Post by Jirka » Wed Jun 12, 2019 11:00 pm

The reference is given in the HYDRUS-1D manual. J.

ghassemi
Posts: 5
Joined: Fri May 17, 2019 3:21 pm
Location: Canada

Re: Cosine function for variation of precipitation

Post by ghassemi » Thu Jun 13, 2019 3:21 pm

Hi Jirka,

Thank you for your quick reply.
Fayer (2000)'s paper only describes the variations in potential evaporation and transpiration during the day.
I am looking for a rational explanation for cosine distribution of daily precipitation as considered in HYDRUS-1D.

Thank you,
Ali

Jirka
Posts: 4714
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Cosine function for variation of precipitation

Post by Jirka » Thu Jun 13, 2019 4:40 pm

It is some 20 years since I implemented this, so I do not remember all the details. I can see in the HYDRUS manual that I do not clearly reference this to Fayer (2000). Perhaps check the source code of the program that Fayer (2000) documents. If it is not there, then it may be only my modification. J.

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