Two-Color Dual-Polarization Pulsed Bistatic Lidar for Measuring Water Cloud Droplet Size

The concept of a pulsed bistatic lidar for measuring water cloud particle size is presented. The method uses a two-color laser and a receiver with a polarization analyzer located at a suitable scattering angle. The dependence of Mie scattering on scattering angle, wavelength, and polarization is used to derive water cloud droplet size. The measurement was simulated for the C₁ and C₂ clouds, and the technique for determining mode radius was studied. The result shows the lidar system with a two-wavelength laser (1064 nm and 532 nm) and a dual-polarization receiver fixed at a scattering angle of around 178 deg can be used to measure a cloud particle size (mode radius) of 4 to 12 μm. Evaluation of the effect of multiple scattering showed that the method can be applied not only for the measurement at the cloud base but also in the cloud where multiple scattering is not negligible.