Hi,

I am calculating a mean for Van Genuchten parameters, from 5 samples of the same soil using RETC.

I want to compare the RMSE from some Hydrus simulations (inverse modeling) with RMSE from RETC. I think RETC do not provide RMSE directly.

So I ask:

Should I use the sum of squares to do it?

This RMSE from weighted value the best way to compare with the RMSE provided from Hydrus output? (the Hydrus inverse modeling was made just with water content values. No pressure values)

As example, I have this:

Should I do this?

RMSE (Ret) = (1/500 * (0.05232))^0.5 = 0.01

RMSE (Cond) = (1/500 * (0.01584))^0.5 = 0.005

RMSE (All) = (1/1000 * (0.06816))^0.5 = 0.008

(500 data points input on retention data and more 500 on conductivity data.)

And use the RMSE (All)?

Thanks a lot.

## RMSE on RETC

### Re: RMSE on RETC

What you suggest makes sense for retention and conductivity data (if you use unweighted SSQ). I do not think that it make sense for "all" data, since each has different units. This is how these values are calculated:

SSQ1=0.0

SSQ2=0.0

SSQW1=0.0

SSQW2=0.0

do 84 i=1,NWC

R(i)=Y(i)-F(i)

SSQ1=SSQ1+R(i)**2 ! unweighted retention data

SSQW1=SSQW1+(R(i)*W(i))**2 ! weighted retention data

84 continue

do 88 i=NWC1,NOB

R(i)=Y(i)-F(i)

SSQ2=SSQ2+R(i)**2 ! unweighted conductivity data

SSQW2=SSQW2+(R(i)*W(i))**2 ! weighted conductivity data

88 continue

SSQ=SSQ1+SSQ2 ! unweighted all data

SSQW=SSQW1+SSQW2 ! weighted all data

I do not think that HYDRUS and RETC are using weights in the same way and thus I would not try to compare weighted SSQ.

J.

SSQ1=0.0

SSQ2=0.0

SSQW1=0.0

SSQW2=0.0

do 84 i=1,NWC

R(i)=Y(i)-F(i)

SSQ1=SSQ1+R(i)**2 ! unweighted retention data

SSQW1=SSQW1+(R(i)*W(i))**2 ! weighted retention data

84 continue

do 88 i=NWC1,NOB

R(i)=Y(i)-F(i)

SSQ2=SSQ2+R(i)**2 ! unweighted conductivity data

SSQW2=SSQW2+(R(i)*W(i))**2 ! weighted conductivity data

88 continue

SSQ=SSQ1+SSQ2 ! unweighted all data

SSQW=SSQW1+SSQW2 ! weighted all data

I do not think that HYDRUS and RETC are using weights in the same way and thus I would not try to compare weighted SSQ.

J.

### Re: RMSE on RETC

Thanks a lot for the answer. It helped me a lot.