Concentrations and Source Areas of Ice Nuclei in the Alaskan Atmosphere

Abstract

Atmospheric ice nucleus concentrations were measured by the filter method daily for ten months at three ground sites in Alaska to determine the influence of long-range nucleus sources on the concentrations. The results indicate a seasonal variation in nucleus concentration with a winter minimum and a north-to-south trend in the increasing average concentration. Some episodes of high concentrations were correlated with 500 mb isobaric transport from Eurasia and 700 mb cyclogenesis over Alaska. These results suggest that local nucleus sources play a dominant role in the seasonal variation, while some individual episodes are caused by external or regional influences.