The Coastal Waves 96 field program made an extensive set of lidar measurements of the marine atmospheric boundary layer off the coast of California using the NCAR Scanning Aerosol Backscatter Lidar (SABL). The majority of the measurements are of stable conditions over the cool upwelling waters. SABL provides an exceptionally high spatial resolution of 3.75m in the vertical by approximately 5m in the horizontal; these measurements are ideally suited for the study of boundary layer top, cloud top, and entrainment zone structure under stable conditions, where turbulent motions are expected to be small in scale. The vast majority of previous studies of entrainment zone structure have focused on convective conditions, and there are few published measurements for the stable case.

A Haar wavelet covariance transform is used to determine the boundary-layer top from the lidar backscatter profile. This paper will present measurements of the structure of the entrainment zone for both cloud-topped and cloud-free cases within the stable marine atmospheric boundary layer, and compare those results with previous studies for convective conditions.

A companion poster presentation (Finding Boundary Layer Top for the Stable Layer: Application of a Haar Wavelet Covariance Transform to Lidar Observations) will examine technical aspects of the application of the algorithm to non-ideal data.