DOI: 10.14489/td.2017.01.pp.040-043

Abdulov R. N., Abdullaev N. A., Eminov R. A., Asadov H. H.
THE METHOD FOR TWO WAVELENGTHS CALIBRATION OF SUN PHOTOMETERS UPON TWO OPTICAL AIR MASSES
(pp. 40-43)

Abstract. It is noted that the major method used for calibration of sun photometers is still the method of Langley. The major shortage of the method of Langley is temporal instability of drawn graphical diagrams caused by instability of optical depth of atmospheric aerosol. The temporal instability of atmospheric aerosols optical depth leads to change of steepness of drawn up diagrams and as a result to random shifts of graphically calculated calibration quantity. Another significant shortage of Langley method is lack of fully analytical formula for calculation of calibration quantity and necessity to draw the graphics. There are some modifications of the Langley method, for example an analytical method which makes it possible to calculate analytically the calibration quantity upon two optical masses, where the instability of basic method remains. The two wavelength methods for calibration of sun photometers upon two optical masses suggested in this article make it possible to remove the impact of atmospheric conditions on results of calibration inherent for known one wavelength method realized upon two optical masses. The suggested method make it possible to increase the accuracy of sunphotometric measurements of atmospheric trace gases and aerosol.

Keywords: sun photometer, calibration, optical air mass, error, aerosol, atmosphere.