CLOUD CONDENSATION NUCLEI ASSOCIATED WITH ARCTIC HAZE

Measurements are reported of the cloud condensation nucleus spectrum of Arctic haze from which it has been possible to deduce that a large fraction of the cloud active nuclei are soluble salts. On the basis of these findings, maximum supersaturation during the formation of Arctic stratiform clouds is expected to be around a third of a percent (for updrafts of 10cm s** minus **1). Soluble nuclei down to 3 minus 4 multiplied by 10** minus **6 radius would be nucleated under these conditions. These inferences suggest that clouds forming in polluted Arctic air may contain relatively small (i. e. 10-30 cm** minus **3) cloud droplet concentrations.