Abstract
Lidar measurements of the thickness of the atmospheric entrainment zone are presented. The measurements were obtained in central Illinois during 6 days of clear-air convection.
A new method was developed to monitor the potential temperature jump across the entrainment zone. A single early morning temperature sounding and continuous lidar measurements of the mixed-layer height provide potential temperature jump values which agree well with in situ observations.
Lidar measurements of the thickness of the entrainment zone normalized by mixed-layer depth are presented as a function of a ‘convective’ Richardson number; these values show reasonable agreement with published laboratory results. The lidar observations span a wider range of mixed-layer depths and contain higher values of the normalized entrainment rate (dh/dt)/w * than those observed in tank studies. Both lidar and tank results show that simple parcel theory does not properly predict entrainment-zone thickness. During this experiment which examined mostly high entrainment conditions, the normalized entrainment-layer thickness was linearly dependent on entrainment rate.
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Boers, R., Eloranta, E.W. Lidar measurements of the atmospheric entrainment zone and the potential temperature jump across the top of the mixed layer. Boundary-Layer Meteorol 34, 357–375 (1986). https://doi.org/10.1007/BF00120988
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DOI: https://doi.org/10.1007/BF00120988