Open AccessCloud condensation nuclei spectra and polluted and clean clouds over the Indian Ocean
Author(s) -
Hudson James G.,
Yum Seong Soo
Publication year - 2002
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001jd000829
Subject(s) - cloud condensation nuclei , adiabatic process , environmental science , entrainment (biomusicology) , atmospheric sciences , liquid water content , condensation , cloud physics , cloud computing , meteorology , physics , aerosol , thermodynamics , rhythm , acoustics , computer science , operating system
Cloud condensation nuclei (CCN) and cloud microphysics measurements with various levels of pollution over the Indian Ocean showed roughly linear relationships. Estimates of adiabatic cloud droplet concentrations make more useful comparisons than average droplet concentrations, which are reduced by entrainment and averaging artifacts. Adiabatic cloud droplet estimates indicate higher cloud supersaturations. As predicted, the supersaturations were suppressed by higher CCN and cloud droplet concentrations. However, the actual suppression of cloud supersaturations was not as great as these comparisons indicated because many small cloud droplets were below the detection limit of the Forward Scattering Spectrometer Probe (FSSP), especially in the polluted air. Predictions of droplet concentrations based on CCN spectra and updraft velocities matched estimates of adiabatic cloud droplet concentrations in the clean air but overpredicted adiabatic estimates of polluted cloud droplet concentrations largely because of the undercounting of smaller droplets in polluted air masses. Thus, when all things were considered, a reasonable level of closure was found between predictions of droplet concentrations and adiabatic estimates of cloud droplet concentrations.