Dear Sridhar,

thanks also to you for the fast reply!

However, I am not sure, whether your assumption is correct that the
MT-CLIM software needs tweaking in the sourcecode to produce reliable
estimates.
If I am not mistaken, the beauty of this model lies in its quite
"universal" approach.
Rosalind et al. (2004 Agron. J. 96:391-397) for instance state: "The
more complicated approach of the Bristow-Campbell model used in the TR
model was successful in eliminating the need for site-specific
calibration of coefficients, as required by other forms of the
Bristow-Campbell model."

Have you used the MT-CLIM software yourself?

Regards,
Rolf


> -----Original Message-----
> From: Sridhar Gummadi [mailto:[log in to unmask]]
> Sent: Tuesday, July 06, 2010 16:01
> To: Sommer, Rolf (ICARDA)
> Subject: Re: solar radiation prediction with MT-CLIM
>
> Dear Rolf,
>
>   You need to adjust the parameters according to the study area, as
> the source code is provided you can play around with the constants
> used in the program and check the literature too for these parameters
> for your study area.  Alt +f11, to see the program source code and the
> constants used.
>
> Thanks
> Sridhar
>
>
>
>
> On Tue, Jul 6, 2010 at 1:40 PM, Sommer, Rolf (ICARDA)
> <[log in to unmask]> wrote:
> > Dear all,
> >
> >
> >
> > I am using MT-CLIM for Excel (0.4 beta;
> >
http://www.ntsg.umt.edu/models/bgc/index.php?option=com_weblinks&catid=1
> > 8&Itemid=32) to estimate solar radiation and humidity from daily
Tmax,
> > Tmin and precipitation. (This is based on the improved
Bristow-Campbell
> > model invented by Thornton and Running in 1999.)
> >
> > However, I am getting somewhat confused by the magnitude of the
results
> > produced:
> >
> > MT-CLIM predicted solar radiation in summer often exceeds 500
Watt/m2
> > (daily average ...I assume...), i.e. 40 MJ/m2/day, whereas
corresponding
> > observed data never surpass 31 MJ/m2/day.
> >
> > Same problem (much too high predicted solar radiation) with the
default
> > data set that is included in the Excel version of the model, meaning
> > that the problem does not lie in my data, but in my apparently
limited
> > ability to make sense out of the results.
> >
> > Anybody who could solve this mystery?
> >
> >
> >
> > Best regards,
> >
> > Rolf
> >
> > ==============================================
> >
> > Dr. Rolf Sommer
> >
> > Soil Fertility and Agro-Ecosystem Modeling
> >
> > International Center for Agricultural Research
> >
> > in the Dry Areas (ICARDA)
> >
> > www.ICARDA.org
> >
> > P.O. Box 5466, Aleppo, Syria
> >
> > Tel 00963 21 2691 2545
> >
> > P Help save paper - do you really need to print this email?
> >
> > ==============================================
> >
> >
> >