Improving the s-shape solar radiation estimation method for supporting crop models.
In line with the critical comments formulated in relation to the S-shape global solar radiation estimation method, the original formula was improved via a 5-step procedure. The improved method was compared to four-reference methods on a large North-American database. According to the investigated error indicators, the final 7-parameter S-shape method has the same or even better estimation efficiency than the original formula. The improved formula is able to provide radiation estimates with a particularly low error pattern index (PI(doy)) which is especially important concerning the usability of the estimated radiation values in crop models. Using site-specific calibration, the radiation estimates of the improved S-shape method caused an average of 2.72 ± 1.02 (α = 0.05) relative error in the calculated biomass. Using only readily available site specific metadata the radiation estimates caused less than 5% relative error in the crop model calculations when they were used for locations in the middle, plain territories of the USA.
Crop Modeling research group, Department of Environmental Informatics, Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, H-1022 Budapest, Hungary. fodornandor@rissac.hu
Nándor
N
Fodor
D000383:Agriculture / Q000379:methods*; D000465:Algorithms; D018533:Biomass; D002138:Calibration; D002980:Climate; D003198:Computer Simulation; D005583:Fourier Analysis; D015233:Models, Statistical; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012993:Solar Energy; D013696:Temperature; D014481:United States