METEOROLOGY AND ATMOSPHERIC CHEMISTRY 



83 



».-i^ 



Fig. 6 SEAREX atmospheric sampling tower in operation on Bolcandretolc Island in 1979. 



approach 1 mg m" up to several meters downwind from 

 the surf line (Duce and Woodcock, 1971). Samples of 

 atmospheric salt collected from the top of the tower at 

 Enewetak were not affected by the surf zone, as the high 

 concentrations produced on the shoreline were carried 

 beneath the top of the tower by the strong trade winds. 

 Thus the atmospheric salt concentrations measured on the 

 tower were representative of concentrations expected over 

 the open ocean at that elevation (18 m) above the sea sur- 

 face. 



Measured 18-meter-high salt concentration at Enewetak 

 ranged from about 15 fiq m~'^ at winds of 5 to 6 ms~' to 

 about 30 fiQ m^"^ at winds of 10 ms~' (McDonald et al., 

 1982). The higher winds result in more wave and whitecap 

 activity and thus higher atmospheric salt concentrations. 



The mass median radius of the sea salt collected on 

 the tower was 3 to 4 /zm at the mean observed relative 

 humidity of 80%, and generally 90% or more of the salt 

 was present on particles with radii greater than 1 nm. 

 McDonald et al. (1982) showed that the rate of deposition 



