Ground-based lidar measurement of liquid water content and effective droplet diameter in water clouds: instrumentation, retrieval method and results

摘要

Lidar probing of dense water clouds gives rise to significant multiple scattering contributions. Instead of trying to mitigate the effect, we have developed methods to collect and angularly resolve the multiple scattering returns. The proposed retrieval method combines these measurements with a rapid semi-empirical computation method of the lidar multiple scattering contributions. Solutions are calculated for the extinction coefficient, tlie effective droplet diameter, the liquid water content and the rain rate. The paper reviews the main measurement methods, discusses briefly the concept and implementation of the retrieval technique, presents validation results obtained from Monte Carlo simulations, and compares lidar solutions for liquid water content and effective droplet diameter with in-cloud aircraft measurements. Good correlation is demonstrated for both simulation and field data. We conclude that multiple-scattering lidar is a practical option for the remote sensing of water cloud microphysical parameters up to the lidar penetration depths of typically 200 m.