Vol. 18, issue 07, article # 6

Abstract:

The spectral dependence of aerosol extinction coefficient (AEC) for several hundred of thousands of stratospheric aerosol and PSC realizations has been calculated based on Mie-theory algorithms. The means and covariance matrices for different scenarios of PSC transformation have been constructed. It has been shown that it is possible to use only 4 eigenvectors of AEC covariance matrices for approximation of AEC spectral dependence with 5% accuracy in 0.29 to 1.56 mm spectral region. The possibilities of retrieving the size distribution function (SDF) and its moment from AEC measurements with 5-25% accuracy have been studied. The regression method makes it possible to decrease essentially the relative a priori uncertainty of SDF of combined ensemble for the size range of 0.06-2 mm. This decrease is maximal for the 0.5-0.7 mm size particles (from 400 to 60%). Absolute a priori uncertainty of SDF decreases (from 3.5 to 0.35 cm^-3) in the size range of about 0.3 mm. In the range of the uncertainty curve maximum (0.1mm), the absolute a priori uncertainty decreases from 7.6 to 3.8 cm^-3 at the 5% AEC error, and to 5.5 cm^-3 at 25%. Total cross-section area S is the best-determined value from all SDF moments. For combined ensemble, a priori uncertainty of S decreases by 4-5.5 times.