Cloud condensation nucleus (CCN) spectral data are presented for the A
rctic in spring, which considerably augment the existing meager CCN da
tabase for the Arctic. Concurrent measurements of sulfate mass suggest
that most of the CCN were commonly not sulfate. Sulfate was more clos
ely associated with particles below the CCN size range. Some measureme
nts of the microphysical structure of Arctic stratus clouds are also d
escribed.