Method for Aerosol Parameter Estimation Error Analysis - Consideration of Noises Included in the Measured Solar Direct and Diffuse Irradiance

Method for error analysis of aerosol parameter estimation with assumed noises which are included in the measured solar direct and diffuse irradiance is proposed. The noises included in the measured solar direct and diffuse irradiance are assumed to be Chi-Square probability density function due to the fact that the measured irradiance is represented as output power which is square of output voltage which corresponds to the measured irradiance which is assumed to be normal distribution of probability density function. Aerosol parameters (refractive index which consists of real and imaginary parts, size distribution which is represented by Junge parameter) are estimated with the measured solar direct and diffuse irradiance which corresponds to the acquired output power of the measuring instrument which allows measurement of solar direct and diffuse irradiance. Through experiments with the measured solar direct and diffuse irradiance, it is found that the estimation accuracy of imaginary part of aerosol refractive index is the most sensitive to the added noises followed by size distribution of Junge parameter and real part of aerosol refractive index. Keywords—Aerosol; Atmospheric optical depth; Solar irradiance; Solar direct; Solar diffuse; Aereole; Junge parameter; Size distribution; Real and imaginary parts of refractive index