Measurements of atmospheric /sup 222/Rn at San Nicolas Island and over nearby California coastal areas during CEWCOM-78. Memorandum report

Shipboard and island measurements show that clean maritime air prevailed over San Nicolas Island, California, for two periods of a day or more each during the twelve days of data collection and moderately continental air prevailed for the remainder of the time. Moderately continental air was encountered out to 200km from shore on 8 and 9 May on a dogleg course from Monterey to the San Nicolas Island area. Maritime air was encountered throughout the direct return trip along the coast, showing that the relative continental/maritime nature of the air at a given location in the area is more dependent upon prevailing winds than on distance from land. Radon measurements at the NRL tower site on San Nicolas Island were in good agreement with shipboard data throughout the area, suggesting a relatively uniform distribution of air over a large area, whether it be maritime or moderately continental. The moderately continental conditions prevailing at San Nicolas Island are not unlike those previously encountered for one or more days in remote Pacific areas in air of Asian origin.