Research On Microphysics Parameters Of Cloud Based On Multiple Scattering Properties

Cloud is an important factor affecting atmospheric radiation transmission,which has important effects on the balance of radiation budget of the terrestrial atmosphere system.Hence,many researchers have used different kinds of passive and positive detection ways to study cloud microphysical properties.As liquid water content and cloud droplet effective radius are important parameters affecting this process,it is essential to measures these two parameters.Under the development of scattering theory,several researchers propose that cloud microphysical parameters can be measured based on multiple-scattering theory.It is because that the cloud has shorter free-path,which may cause multiple scattering more easily.As multiple scattering have great relationship with the concentration of particle in medium,so cloud microphysical properties can be studied with the aid of multiple scattering.The scattering characteristic of cloud is calculated based on Monte Carlo simulation and an algorithm to retrieve liquid water content and cloud droplet effective radius was proposed.A multiple-field-of-view lidar system was constructed based on simulation results with it being used to observe liquid cloud in the north suburb of Nanjing.These two parameters were retrieved combining observation data with proposed algorithm.This algorithm was verified by comparing the retrieve results with GPM satellite product under the aid of theoretical research.Also,the polarization characteristic of liquid cloud was studied based on Monte Carlo simulation and the relationship between degree of polarization and multiple-scatter factor were studied.Based on simulation result,we find that sensibility of polarization decreases as multiple scattering enhances,which means that degree of polarization will be saturated under certain condition and saturated value varies with field of view.A multiple field of view polarization lidar system was constructed and its calibration parameter was determined to observe depolarization characteristic of cloud.Based on our analysis,the observed data has good agreement with simulated one.Finally,the driving factors(aerosol and water vapor)of liquid cloud nucleation and water source dynamics and its retrieve method was studied.An improved method was used to retrieve the data from dual wavelength and dual Raman lidar system.Aerosol profiles from near-ground to the bottom of stratosphere and water vapor profiles from near-ground to 12 km were obtained,which provides accumulation of raw data for studying liquid cloud nucleation and water source dynamics...