Μελέτη των οπτικών και φυσικών ιδιοτήτων των αιωρούμενων σωματιδίων με μεθόδους τηλεπισκόπησης laser

Abstract

The object of this Thesis is the study of the aerosol optical and microphysical properties derived by using remote sensing techniques. For this aim a lidar [= light detection and ranging] system is used which is located at the LaboratoryThe motivation and the objectives of this thesis are given in the first chapter.The description of the system, the basic definitions of parameters and data analysis methods with which it deals this thesis constitute the second chapter.The experimental determination of overlap function is also presented in the frame of the second chapter.In the third chapter we present the statistical analysis of the lidar-derived aerosol optical properties observed at Thessaloniki from 2000 up to 2007.Concretely, we study extinction coefficient, backscatter coefficient, lidar ratio and Ångström exponent of aerosol particles. The mean optical depth for the period of study of is in the order of 0.6, while the contribution of particles of free troposphere in the total optical depth exhibits variability from 2% to 84%.We have found that optical depth presents two distinct maxima one during Spring time and one during Summer months. To investigate this seasonality we have used additional synergistic tools such as DREAM model to identify the cases where aerosols from Saharan dust are observed and satellite data to identify those cases that biomass burning aerosols are observed. We have associated characteristics signatures for each source of aerosols using lidar ratio and Ångström exponent values. par mol par mol z par Ra mol Ra z Ra Ra z Ra Ra par mol z