An Initial Application of Polarization Lidar for Orographic Cloud Seeding Operations

Abstract

Ground-based polarization lidar measurements have been obtained in conjunction with a commercial cloud seeding program to evaluate the potential of pulsed laser remote sensing techniques for increasing the effectiveness of orographic cloud seeding operations. The lidar measurements, supplemented by microwave radar cloud top and rawinsonde data, are shown to aid in the determination of seeding criteria. Our real-time seed, no-seed decisions based on lidar polarization measurements of cloud ice-water balance compare favorably with the declarations issued locally by the project meteorologists. Moreover, the lidar has detected changes in cloud layer structure and ice-water balance brought about by aerial seeding operations which are quite distinct from the background conditions, indicating that lidar observations may also find application as part of a physical evaluation method of seeding effects. It is concluded that despite the range limitations of lidar, the application of the remote sensing techniques can make important contributions to orographic cloud seeding operations and research.