Broadband radiation methods to determine aerosol optical depth and imaginary part of its refractive index and their applications

摘要

Two broadband radiation methods are developed to determine aerosol optical depth and the imaginary part of its refractive index. One is broadband extinction method to determine aerosol optical depth by using hourly/daily accumulated pyrheliometer data. Another is broadband solar radiation method to retrieve the aerosol imaginary part from joint pyrheliometer/paranometer data. Furthermore, aerosol optical depths over 11 meteorological observatories in China during 1980-2000, the aerosol imaginary parts and its single scattering albedoes in Beijing and Shenyang during 1 1993-2000 are retrieved from pyrheliometer/paranometer data by using the methods. Based on the retrieval results, the variation trends of the aerosol optical depths and its imaginary parts, the effects of Pinatubo eruption in 1991, sand-dust event and fossil fuel burning on them are empirically analyzed.