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A Model of Drizzle Growth In Warm, Turbulent, Stratiform Clouds
Author(s) -
Nicholls S.
Publication year - 1987
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49711347805
Subject(s) - drizzle , turbulence , liquid water content , coalescence (physics) , settling , drop (telecommunication) , cloud physics , mechanics , turbulent diffusion , radiative transfer , environmental science , physics , meteorology , statistical physics , atmospheric sciences , precipitation , thermodynamics , cloud computing , telecommunications , quantum mechanics , astrobiology , computer science , operating system
A model to describe the growth of precipitation sized drops in layers of warm, stratiform cloud is developed which combines the effects of stochastic turbulent diffusion with explicit microphysical calculations. the representation of diffusion is consistent with measured turbulence statistics, reproduces standard results and is used to define an ensemble of Lagrangian trajectories within which the effects of phase change, stochastic coalescence and vertical exchange due to gravitational settling can be calculated. Mean drop size distributions are predicted as functions of height within the cloud. The inclusion of realistic levels of turbulence is found to produce greatly increased numbers of larger ( r >100 μm) drops throughout the depth of the cloud. the modelled steady‐state drop size distributions show good agreement with corresponding aircraft measurements in a case study. the effects of changing the turbulence intensity, cloud depth and liquid water content on the distribution of larger drops are investigated and implications for the cloud layer water balance and the cloud radiative properties are also considered.