Dear Arnold,
estimating solar radiation is a quite common issue, and you can find a number of publications providing guidelines how to best proceed.
E.g.
Hunt, L.A., L. Kuchar, C. J., Swanton 1998. Estimation of solar radiation for use in crop modeling. Agricultural and Forest Meteorology 91, 149-300.
Rivington, M., Matthews, K. B., and Buchan, K. A. 2002 comparison of methods for providing solar radiation data to crop models and decision support systems. http://www.wca-infonet.org/servlet/BinaryDownloaderServlet?filename=1065620840070_wdds25.pdf&refID=113918
This one might also be interesting for you:
Aggarwal, P.K. 1995. Uncertainties in crop, soil and weather inputs used in growths models: implications for simulated outputs and their applications. Agricultural Systems 48:361-383.
I used the Bristow-Campbell model myself, and it produced some reasonable values, though not as reliable as for instance using extra-terrestrial radiation estimates in combination with sunshine hours.
As far as I remember (did this some years back) you need some calibration data sets for the Bristow-Campbell model.
You could use for instance the RadEst software (if you can find it in the www). This is quite straight forward and should enlighten you how to derive the b and c coefficients.
On the other hand, you say you need these data for province level. Can't you find any weather station nearby that recorded solar radiation?
Regards,
Rolf
==============================================
Dr. Rolf Sommer
Agro-Ecosystem Modeling
Current Address:
International Center for Agricultural Research
in the Dry Areas (ICARDA)
P.O. Box 5466, Aleppo, Syria
Tel 00963 21 2691 590
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==============================================
> -----Original Message-----
> From: DSSAT - Crop Models and Applications
> [mailto:[log in to unmask]] On Behalf Of Arnold Salvacion
> Sent: Thursday, August 14, 2008 05:37
> To: [log in to unmask]
> Subject: Estimation of solar radiation
>
> Dear Colleagues,
>
>
>
> I am currently modeling the impact of climate change in the
> Philippines. I have only had monthly values of rainfall, tmax (maximum
> temperature) and tmin (minimum temperature). Thus, I still need to
> estimate
> solar radiation data for each province. Can anyone help me or have an
> idea on
> how to estimate solar radiation data from these available datasets? I
> am
> thinking to use the Bristow-Campbell model but I do not know how to
> compute for
> the b and c coefficient of the model.
>
>
>
> Best regards,
>
>
>
> Arnold
>
>
>
> Arnold R. Salvacion
> ___________________
> M.Sc. Environmental Science Student
> School of Environmental Science and Management
> University of the Philippines, Los Baņos
> College 4031, Laguna, PHILIPPINES
> Telefax: 049.536.2381
> E-mail: [log in to unmask]
> [log in to unmask]
>
>
>
>
>
>
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