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CCN and cloud droplet concentrations at a remote ocean site
Author(s) -
Hudson James G.,
Noble Stephen
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl038465
Subject(s) - cloud computing , environmental science , geology , meteorology , oceanography , remote sensing , computer science , geography , operating system
Extensive aircraft measurements over the mid Pacific displayed unexpectedly high overall average concentrations of condensation nuclei (CN) of 379 cm −3 , cloud condensation nuclei (CCN) at 1% supersaturation (N CCN ) of 301 cm −3 , and total cloud droplets (N c ) of 139 cm −3 . Factor of two variations in average N CCN and N c among 11 flights produced a positive correlation coefficient (R) of 0.81. Updraft velocity (W) was also positively correlated with N c but with lower R. Comparisons with a more traditionally maritime project (RICO), which had higher average W clearly demonstrated the role of W in determining N c . Correlations of N CCN with concentrations of larger droplets were negative but the R switched back to positive for concentrations of largest cloud droplets with N CCN . The explanation offered for this double reversal of R for N CCN with droplet concentrations greater than various sizes suggests yet another influence of the aerosol on cloud microphysics.