INFORMATION CONTENT OF MULTIWAVELENGTH LIDAR DATA ON THE BASE OF EIGENVALUES ANALYSIS

摘要

Multiwavelength Raman lidar technique in combination with sophisticated inversion algorithms has been recognized as a new tool to derive information about microphysical properties of atmospheric aerosols. The optical input parameter sets, which are provided by respective aerosol Raman lidars, are at the theoretical lower limit at which these inversion algorithms work properly. For that reason there is ongoing intense discussion on the accuracy of the inversion methods used for the retrieval of the microphysical parameters, and the possibility of the simultaneous retrieval of the particle size distribution and the complex refractive index. In our presentation we use eigenvalue analysis to study the information content of multiwavelength lidar data. Such an analysis provides us, on a rather mathematical base, more insight on the limitations of these inversion algorithms, it allows us to determine the range of particle microphysical parameters within which the complex refractive index can be derived with sufficient accuracy, and to estimate corresponding uncertainties. It furthermore shows the importance of the simultaneous use of backscattering and extinction coefficients for the retrieval of microphysical parameters.