Aerosol Parameter Estimation Method Utilizing Solar Direct and Diffuse Irradiance Measuring Instrument without Sun Tracking Mechanics

Abstract

Estimation method of aerosol parameter by means of solar direct and diffuse irradiance measurements with the proposed instrument of fiber-ball radiometer without sun tracking mechanics is proposed. Sky-radiometer and aureole-meter is well known instrument which allows measurements of solar direct and diffuse irradiance for estimation of aerosol parameter. The proposed fiber-ball radiometer also allows solar direct and diffuse irradiance measurements and is comparatively light as well as is composed without any mechanics so that it is portable and is enable to bring anywhere you want including test sites for field campaigns. Meanwhile, it is not always that the fiber-ball instrument points to the sun due to the error of the sun ephemeris calculations as well as sun track do not match to the actual one. Influence due to pointing error on aerosol parameter estimation error is clarified. Possible maximum pointing error may cause some error on aerosol parameter estimation. Experimental results show that 0.43%, 42.23%, 2.12% root mean square errors are suspected for real and imaginary part of refractive index and Junge parameter as of 1.747, 0.0056 and 3.0 of typical case of atmosphere.