Eastport 

 Portland 

 Boston 

 Newport 



Battery 

 Atlantic City 

 Hampton Roods 



Southport 



Charleston 

 Mayport 



Miami 

 Key West 



Tampa 

 Cedar Keys 

 Pensocolo 



Galveston 

 Port Isobel 



Figure 6. Observed monthly MSL at USC&GS Atlantic coast 

 tide stations, 1930-40 (Harris, 1963). 



datum (in use in 1963) for a period of 1 month. The local sea level has been established for 

 some earlier time periods as discussed in Section IV, and the sea is rising, relative to the 

 land, in this area. Thus, the mean of the observed record Ues sliglitly above the established 

 local MSL. The vertical bars plotted above the curves indicate months in which hurricanes 

 passed near the tide gage. In general, the official local sea level datum differs from the 

 NGVD (discussed later) and the observed MSL of the period shown in the figure. 



Perturbations in sea level with periods longer than 1 year are shown in Figure 7. A 

 general trend for rising sea levels, relative to the land, is clearly evident at Honolulu, Hawaii, 

 and Cristobal, Canal Zone ; a trend toward falling sea levels, relative to the land, is shown for 

 Yakutat, Alaska. The means for individual years meander above and below the trend Une in 

 an erratic fashion. The accepted explanations for the secular trends in sea level at these and 

 other tide stations are discussed in Section VI. 



The sample tide graphs presented in this section show a variety of phenomena that were 

 not well known to the scientists who developed the tidal theory (Sec. Ill) or the engineering 

 definitions (Sec. IV). These examples, however, give useful background information 

 concerning the phenomena which must be considered later in tliis report. 



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