Field studies of the effect of entrainment upon the structure of clouds at Great Dun Fell

Abstract

A description is given of experiments and calculations performed to investigate the effect of the entrainment of undersaturated air upon the microphysical structure of cap clouds at Great Dun Fell, Cumbria. Three case studies are presented: in I the properties of the cloud were essentially adiabatic; I1 provided evidence for mixing intermediate between the homogeneous and extreme inhomogeneous types ; in 111 the mixing was extremely inhomogeneous. Consistent with this picture, the time constant for turbulent erosion of the entrained parcels of air is significantly greater in 11 than in 111. Spectral changes observed in I1 and I11 agree well with predictions from a diffusive model of mixing (Baker and Latham 1982).High frequency acoustic sounders. Atmos. Envir., 13, 347- 350. Microphysics of Clouds and Precipitation, D. Reidel (pub.). The measurement of cloud droplet spectra. Znt. Con/. Cloud Phys., Boulder, Colorado, 576-580. A field study of nocturnal stratocumulus: 111. High resolution radiative and microphysical observations. Quart. J. R. Met. SOC., 108, 145-166. An asymptotic theory of incompressible boundary-layer flow over a small hump. J. Fluid Mech., 101, 647-670.

Cloud Adiabaticity and Its Relationship to Marine Stratocumulus Characteristics Over the Northeast Pacific Ocean

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Investigation of the adiabatic assumption for estimating cloud micro- and macrophysical properties from satellite and ground observations

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