The uncertainties of the experimental data and the predicted data are investigated.
For these experimental data,the sources of uncertainty include the accuracy of the sensor and the error due to the set up of the sensor.
The total uncertainty of the measured data is estimated from the root sum square of all bias uncertainties associated with the measurement.
The root sum square of the sensor errors (i.e. non-linearity, temperature dependence of sensitivity, tilt error, directional error and zero offset of the pyranometer) as published by the manufacturer are used to calculate the uncertainty due to sensor errors.
The uncertainty due to the sensor errors (CM 6B and CMP 6) is estimated to be about ±8.1% of the measured solar radiation.