32 



Experience indicates that waves generated by sea breezes 

 have breaking heights averaging about 2 feet and periods of 

 about 5 seconds. They should reach their maximum development 

 at about 1500 or 1600 hours. Although some information can 

 be obtained on the fetches, durations, and velocities of sea 

 breeze situations, it is difficult and probably unwise to 

 interpret these data. In theory winds have to obtain an 

 average velocity of about 10 knots before they are able to 

 exert sufficient tractive force on the water surface to start 

 the growth of waves. Sea breezes, from observation, generally 

 have a velocity of about this order of magnitude. 



WATER TEMPERATURE 



Methods 



Temperature data have been collected using two methods. 

 The first is surveys of the area accomplished by traversing 

 a network of stations at cruising speeds making bathythermo- 

 graph casts at short intervals along each traverse line. In 

 this way it is possible to obtain water temperatures to a 

 depth of 200 feet throughout the bay in six or seven hours. 



The second method consisted of occupying a grid of hydro- 

 graphic stations and obtaining salinities as well as tempera- 

 tures at various depths in the water column using reversing 

 thermometers and Nansen bottles, or at the surface by bucket 

 samples. 



The bathythermograph grid is best adapted to a detailed 

 study of temperature conditions. Hydrographic stations are 

 required to obtain data on the various water masses and types. 



