Comparison of experiment and simulation of range (time)-resolved laser multiple scattering in cloud

Laser multiple scattering phenomena occurring inside a cloud were experimentally confirmed by showing the spread of the scattered laser light as a two-dimensional spatial distribution image. By changing the gate delay time of a CCD camera, range-resolved scattering images were obtained with a gate time width of 100 ns, which corresponds to a resolution of 15 m cloud depth. The size of the scattering area enlarged just after the laser pulse hit the cloud, and gradually decreased as the beam went deeper inside the cloud where extinction overcame the multiple scattering. An extinction coefficient of 3.62x102 [ m-1] was calculated from the laser beam transmission. The particle size distribution of the cloud was derived to fit the obtained extinction coefficient. A Monte Carlo simulation using the new distribution function reproduced the experimental scattering image very well. This new experimental and simulation method to show the multiple scattering as a spread image will provide informative knowledge for cloud lidar observations.