This study investigates the impacts of meteorological data sources on a cropping systems simulation models estimate of crop yield, and quantifies the uncertainty that arises when site-specific weather data are not available.
The impacts of using on-site observed precipitation and temperature with estimated solar radiation, and off-site entirely observed meteorological data was tested on the models yield estimates.
The analysis indicates that neighbouring meteorological stations can often be an inappropriate source of data.
This study is an investigation into the sources of crop model errors and biases. As such it was not designed to model crop responses specifically, therefore the model estimates are of general interest only.
Models that represent multiple entities with complex biophysical interactions between them therefore require meteorological data that maintains appropriate values and correlations between variables.
Inappropriate choices of data source can have significant impacts on model estimates (Rivington et al., 2002), introducing uncertainties which manifest themselves as incorrect estimations of magnitudes, absolute values, relative timing and synchronisation.
References:
Rivington, M., Matthews, K.B., Buchan, K., 2002. A comparison of methods for providing solar radiation data to crop models and decision support systems. In: Proceedings of the International Environmental Modelling and Software Society, Lugano, Switzerland, 24–27 June, vol 3, pp. 193–198.
The study was undertaken in the United Kingdom using the following locations (values in brackets are the number of years of weather data available, second value is elevation m asl).
This study used the CropSyst cropping systems model.
Observed precipitation maiximum and minimum temperature, solar radiation and / or sunshine duration data from 24 meteorological stations in the UK were used as input to the CropSyst model.
For sites where solar radiation data was not available, serveral methods were used to estimate it: Campbell-Donatelli, Donatelli-Belllocchi methods using maximum and minimum temperature, and conversion of sunshine duration using the 'Johnson-Woodward' method (See Rivington et al 2005).
