SECT. 2] 



SOLUBLES 



309 



Fig. 5 illustrates one common type of variability of particle size and number 

 distribution with altitude over the sea. Similar distributions are found in 

 conditionally unstable oceanic air near Australia, Hawaii, the West Indies, 

 New England (U.S.A.) and over the central North Atlantic. The particles are 

 largely confined to the lower atmosphere which is convectively or frictionally 

 mixed or mixing. In stable air moving over colder water the ejected particles 



10^ 



mIO 



10- 



10' 



^;— I — I I I 1 1 III 1 — I 11 1 II 



-\ ALT. 



^•^t^Q 153 



10= k ->§.:s;-305 



— I I I Miiy 

 SEA-SALT 



16 9 

 12 3 



8.0 



4 



N 



■^; 





•^ 



305 

 \ 



5 

 T.°C 



-I 



•N* 



'.\ 



% 

 -^•j 



10^ 



10' 



10' 



10- 



SEA-SALT PARTICLE WEIGHTS 



Fig. 6. Example of the effects of the 

 surface cooling and stabilizing of 

 the lower air in confining the major 

 part of the salt aerosols to the 

 regions near the sea surface. April 

 30, 1948, 48° 18'N, 70° 50'W. Wind 

 SW, force 4. 



PARTICLE RADIUS AT 99% R.H. ( ji ) 

 51 no 237 511 



10° 10' lO' lO' 10* lO' 



WEIGHT OF SEA-SALT PARTICLES (jitiq) 



Fig. 7. Wind force effects upon the number 

 and the weight of sea-salt particles in 

 the sub-cloud layer of air over the 

 sea. Samples taken 100 m below base 

 altitudes of local cumulus clouds. 

 Curves read as follows : in force 5 

 wind, there are about 10^ particles 

 m~3 larger than 170 [i[ig or during 

 force 5 winds there are 900 particles 

 m~3 in the weight range of about 

 1100 to 4000 y.[ig. 



are confined to a relatively shallow layer of air near the sea surface, as shown in 

 Fig. 6. 



Fig. 7 shows the average numbers of salt particles associated with winds of 

 various forces in the sub-cloud layer over the sea. This relationship is probably 

 due in major part to the wind-produced "breaking" of waves and the con- 

 sequent trapping of air in the form of multitudes of small bubbles. (The effects 



