Microphysical characterization of mixed-phase clouds

Abstract

A detailed study of mixed-phase clouds associated with frontal systems obtained from a large dataset collected by the Convair 580 aircraft of the National Research Council (NRC) of Canada is presented. The total length of analysed in-cloud legs having total-water content (TWC) > 0.01g m-3 was about 44 × 103 km. The ice-water fraction (μ3 = ice-water content/TWC) had a minimum in the range 0.1 < μ3 < 0.9, and two maxima for liquid clouds (μ3 < 0.1) and ice clouds (μ3 > 0.9). The concentration of particles in glaciated clouds was found to be nearly constant at 2-5 cm-3 for temperatures -35 °C < T < 0°C. The concentration of droplets in liquid clouds decreased with decreasing temperature. The mean volume diameter of particles in ice clouds varied between 20 μm and 35 μm, and in liquid clouds between 10 μm and 12 μm. Both ice- and liquid-water content decreased with decreasing temperature. The results of this study may be used for validation of remote-sensing retrievals, and for weather- and climate-models.