dear Rolf
 
Is this PAR or total short wave? High for both I think. What does a stochastic generator say - ie LARS WG??
 
John R Porter
 
Professor Dr John R Porter
Department of Agriculture and Ecology
Faculty of Life Sciences
University of Copenhagen
Hoejbakkegaard Alle 9
2630 Taastrup DENMARK

Omnes vulnerant, ultima necat...tempus fugit
 
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>>> "Sommer, Rolf (ICARDA)" <[log in to unmask]> 06/07/2010 14:40 >>>
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

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==============================================