ASIM User Forum - [temperature interpolation function]

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From: laila bahgat
Date: 01/26/2004

I'll very much appreciate any clarification about the
following issue:
In model ASM3 copy published in Wat. Res. Vol.39, No.1, PP.
183-193, 1999.
Gujer et al., provided a temperature interpolation function
to interpolate the values of model parameters at any given
temperature using the default values given in this paper for
the parameters at 10 and 20 degrees centigrade.
However when I tried to compute parameter values at
temperature = 15, I got unrealistic values, probably due to
some mistake in computing the term theta.
I think this term should be computed using the relation
given in the paper as: ln(k(T1)/k(T2))/T1-T2
Then the main function is:
k(T) = k(20c).exp(theta.(T-20))

i.e. I understood k(T1) as the parameter value at T1= 10 and
k(T2) as the parameter value at T2=20.
Example: for a paramter whose values at temperatures= 10, 20
respectively = 0.05	0.1	
theta would be 13.86294361	
k(15)= 7.88861E-32
This I think is not correct.
So what went wrong in my computations?
Thank you.

Reply #1
From: laila bahgat
Date: 01/27/2004
Please don't bother responding to the earlier message. The
erroneous results were due to a trivial mistake in coding
theta in Excel.
Thank you.

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