You also may want to try using procedures defined by FAO's Irrigation and Drainage Paper No. 56 at:
http://www.fao.org/docrep/X0490E/x0490e07.htm#solar%20radiation
Regards,
Curt
***********************************************
Curt Reynolds, Ph.D.
Crop Analyst for sub-Saharan Africa
U. S. Department of Agriculture (USDA), Foreign Agricultural Service (FAS)
Production Estimates & Crop Assessment Division (PECAD)
USDA South Building, Mail Stop 1045, Room 6547
1400 Independence Ave, SW, Washington DC 20250 USA
Tel: 202-690-0134, FAX: 202-720-8880
e-mail: [log in to unmask]
************************************************
-----<[log in to unmask]>@inter2@FASNJAU wrote: -----
To: [log in to unmask]@inter2@FASNJAU
From: <[log in to unmask]>@inter2@FASNJAU
Date: 10/26/2006 12:40PM
Subject: Re: Sunshine hours - solar radiation
Dear Rolf,
I would appreciate your sending me the EXCEL spread sheet for converting
sunshine hours to solar radiation.
Thanks and regards
Bijay
------------------------------------------
Bijay Singh
FNA, FNAAS, FISSS
ICAR National Professor
Department of Soils
Punjab Agricultural University
Ludhiana 141 004, Punjab
India
Tel: +91 161 2401960 Ext. 317 (Work)
+91 161 2429796 (Home)
+91 98155 69369 (Mobile)
Fax: +91 161 2400945
Email: [log in to unmask]
-------------------------------------------------------------
----- Original Message -----
From: "Rolf Sommer" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 26, 2006 8:31 PM
Subject: Re: Sunshine hours - solar radiation
> 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
>
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