Dear Constanze,

Not being able to tell you more about how the weatherman software processes
sunshine hours - but why don't you do the calculations yourself? This can be
done in a simple MS-Excel spreadsheet using text-book knowledge. (If you
want, I can send you my version.) Then you can also play around with some
driving variables (e.g. albedo) yourself and do some site-specific
calibration.

Regards,
Rolf

> -----Original Message-----
> From: DSSAT - Crop Models and Applications
> [mailto:[log in to unmask]] On Behalf Of Constanze Böhmel
> Sent: Thursday, October 26, 2006 14:17
> To: [log in to unmask]
> Subject: Sunshine hours - solar radiation
>
> Hello,
>
> I am about to model maize yields in Southern Germany. Unfortunately the
> available weather data contains only sunshinehours. Although the
> weatherman
> in DSSAT v4.0.2.0 converts sunshinehours into solar radiation, the
> result is
> not satisfying at all. The calculated values for the solar radiation are
> too
> low.
> My questions are if you can tell me, how the weahterman converts the
> sunshinehours into solar radiation and which experiences you have made
> with
> this function.
>
> Constanze Böhmel
> ________________________________________________________
>
> Constanze Böhmel
>
> University of Hohenheim
> Institute for Crop Production and Grassland Research
> Fruwirthstraße 23
>
> 70599 Stuttgart, Germany
>
> Tel.: ++49 711-459 22380
>
> Fax: ++49 711-459 22297
>
> E-Mail: [log in to unmask]
> www.uni-hohenheim.de/pflanzenbau