Lidar-Based Characterization of the Geometry and Structure of Water Clouds

Abstract

Abstract Lidar remote sensing measurements of low-level water clouds in the form of vertical soundings and instantaneous (∼1 min) azimuth-over-elevation scans are reported. Retrievals are made of the liquid water content and effective droplet diameter at the same range, time, and angular resolutions as those of the measurements. The results are presented as time–height plots and two-dimensional horizontal maps of the retrieved parameters. The cloud structure is resolved by calculating histograms, spatial autocorrelation functions, and power spectra. The distribution of the horizontal inhomogeneities is characterized over the size range from 10 to ∼1000 m. The Kolmogorov −5/3 power-law dependence is verified in all cases, but the −5/3 regime is broken into two subregimes that are separated by a sudden increase in the energy density level. The results illustrate how lidars can contribute meaningful information on cloud structure at high spatial and temporal resolutions, in near–real time, and over extended periods of time.