Microphysical properties of stratocumulus clouds

Data collected in situ with the Meteo-France Merlin-IV instrumented aircraf t during the EUCREX mission 206 are analyzed to document cloud properties t hat are relevant to the calculation of cloud radiative properties. Ascents and descents through the cloud layer reveal that most of the vertical profi les of liquid water content (LWC) and droplet sizes are close to adiabatic profiles. Analysis of horizontal legs shows that sub-adiabatic regions are characterized by reduced droplet concentrations, while droplet sizes remain close to their adiabatic values at that level. Statistics of LWC, droplet concentration and droplet mean volume radius normalized by their adiabatic values are presented for four distinct regions of the cloud layer. This inf ormation is provided for tests of a parameterization of optical thickness b ased on the adiabatic model. (C) 2000 Elsevier Science B.V. All rights rese rved.