NORTH ATLANTIC 



73 



in the Equatorial Belt on the African side; considerably less often 

 low along the Northeast Trades; more commonly low, again, in the 

 latitudes of the Variables, as well as along the northeast coast of the 

 United States ; but less and less often so to the northward. And the 

 wave pattern, while somewhat skewed, is nearly enough latitudinal 

 for the following table to illustrate the south-to-north gradation in 

 the prevailing heights of the sea, at least in a rough way. 



Table 19. — Maximum, minimum, and mean percentages of low, medium, and high 

 seas in 5° squares for different latitudinal belts of the North Atlantic in August 



The contours for high seas and for low, in different frequencies, 

 as laid down in plates I and II, are self explanatory in most respects. 

 Attention should, however, be called to the prevailing smoothness of 

 the sea along the northeast bulge of South America in the Doldrum 

 Belt between the southern boundary of the Northeast Trades and the 

 northern boundary of the Southeast Trades, on the one side of the 

 ocean, and along the coast of equatorial West Africa from Cape 

 Palmas to the Gulf of Guinea on the opposite side, i. e., between the 

 Southeast Trades and the land. 



The increasing frequency with which seas higher than 3 feet 

 ("medium" according to the code adopted), and even higher than 8 

 feet (2 to 9 percent), are encountered, running out from the African 

 coast into the Southeast Trades (which reach north of the equator in 

 summer), is in line with common experience. 



The situation is similar along the axis of the Northeast Trades, from 

 the African coast between latitudes 20° and 35° N., right across to the 

 northern part of the Lesser Antillean chain, where the sea has been 

 reported in August as "medium" for about 65 percent of the time, 

 which accords with an average strength of about 14 to 16 knots for the 

 Trades, where best developed. In fact, the seas are seemingly more 

 uniform in height along this belt than they are anywhere else in the 

 North Atlantic at this season. Even so, the reports for August have 

 shown a considerable gradation from east to west along the Trades, 

 the sea being somewhat more often high (10 to 14 percent) on the 

 African side than to the westward and in the Caribbean (0 to 8 per- 



