Abstract
In-situ instrument calibration has been assessed at Mt. Waliguan Observatory, China based on continuous CE-318 sunphotometer measurements. The calibration procedure was introduced and calibration results were analyzed. From the analysis results, the measurement data obtained during airmass between 2.0 and 6.0 at AM are suitable for Langley method calibration. The final instrument calibration coefficients were achieved based on more than 10 plot curves with the criteria of relative standard deviation (RSD) less than 0.5% for infrared and visible wavelengths and 1.0% for UV wavelengths, respectively. The in-situ calibration coefficients differed less than 0.5% for infrared and visible wavelengths and 1.0% for UV wavelengths from inter-comparison calibration ones. Based on the analysis results, Mt. Waliguan Observatory is possible for the calibration of sunphotometer, especially in autumn and winter seasons.
