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The microstructure of hill cap clouds
Author(s) -
Carruthers D. J.,
Choularton T. W.
Publication year - 1986
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.49711247107
Subject(s) - cloud base , coalescence (physics) , liquid water content , atmospheric sciences , environmental science , meteorology , turbulence , cloud computing , airflow , radiative transfer , cloud condensation nuclei , microstructure , radiative cooling , mechanics , condensation , humidity , entrainment (biomusicology) , materials science , physics , thermodynamics , optics , aerosol , computer science , astrobiology , rhythm , acoustics , operating system , metallurgy
A cloud microphysical model and a model of airflow over hills are used to examine the microstructure of hill cap clouds. The lifetime of the clouds and the distance travelled by the clouds are both assumed to be sufficiently small so that condensation alone is considered to be important; the coalescence of drops is neglected. The effects of changing (i) the height of cloud base, (ii) humidity fluctuations below cloud base and (iii) incloud turbulence, are described. Process (i) is found to be important, its effect on the cloud microstructure being as great as the effect of changes in the CCN distribution or in the mean wind. Droplet loss to ground, radiative cooling at cloud top and entrainment of dry air are also discussed; these processes may all significantly affect the cloud droplet distribution.