Portugal Current 
The prevailing southward flow off the Atlantic coasts of Spain and 
Portugal is known as the Portugal Current and is part of the general 
clockwise circulation in the North Atlantic Ocean. It is a slow-moving 
current that averages only about 0.5 knot during both winter and summer; 
maximum speed seldom exceeds 2.0 knots north of 4O°N and 2.5 knots south 
of 4OON. 
The current is easily influenced by winds. An interesting relation- 
ship based on almost 25,000 surface current drift observations is shown 
in Table 12. The table compares wind and current observations in the 
region between 35° and 45°N, and between 5° and 10°W within the limits 
of the current shown in Figure 1; it shows the wind and current to be 
most constant during summer, when both set in the same general direction 
at least 50 percent of the time. The higher percent of observations of 
south sets during summer probably indicates that the current is at 
strength during this period and less influenced by short-period changes 
in the wind. The percent of observations in other directions is some- 
what less than in winter and indicates that the wind may cause the 
current to set in any direction for short periods at any time of the 
year and that the flow may even reverse during persistent southerly winds. 
During winter the current still shows a prevailing south set but 
with a smaller proportion of observations; the percent distribution in 
the other directions based on 8 points of the compass ranges between 8 
and 13 percent, with the higher percentages north of 40°N. 
19 
