sea breeze will be greater than if average wave conditions are high. A 

 sea breeze-generated wave will probably not appreciably alter the observed 

 height of swell when the height is 3 feet or greater. This is expected 

 from the form of equation (4). 



Table 4. Observed and approximated wave heights 

 for selected stations in July. 



Station 



Number^ 



Ob 

 Daily 

 (ft) 



serve 



d Mean 

 1600 h 

 (ft) 



ours 



Approximated^ 

 height 



25 



4.0 





4.1 





4.1 



19 



1.2 





1.3 





1.4 



11 



1.7 





1.8 





1.9 



2 



1.2 





1.3 





1.4 



1. Station locations, U.S. Coast Guard-COSOP 

 (Fig. 1) 



2. Assuming superimposed waves from a 10-knot 

 sea breeze with a 10-mile fetch occurring 

 40 percent of the time (see eq. 4). 



VII. COASTAL ENGINEERING APPLICATIONS 



This study indicates that a small but potentially significant 

 increase in average wave height occurs when a sea breeze is present; the 

 increase seems larger at stations in sheltered areas with poor exposure. 

 This effect should be considered in analysis and interpretation of 

 coastal and visual wave data. On the average the increase in height will 

 be slight, as shown by the above analysis, but on a given day this 

 increase may be important. 



The data in this paper show that the sea breeze effect on wave climate 

 varies with geographic region, coastal exposure, and time of year. This 

 information can affect coastal engineering design in the following ways: 



(a) Refining estimates of the amount of down time due to wave condi- 

 tions near the coast. Sea breeze affects wave climate, usually during the 

 summer in the later half of the daylight hours. This fact could improve 

 planning for work boat activity along the coast, especially small working 

 craft like survey launches which would be more affected by the short 

 period of the sea breeze-generated waves. 



(b) Improving the design of harbors. Many marinas and small-craft 

 harbors have large enclosed expanses of water over which sea breeze 

 could generate waves that damage small craft at their moorings. Consid- 

 eration of sea breeze effects in planning may result in harbor layouts 

 to reduce such effects. 



