Gulf of California — Roden 
35 
northerly winds blowing into the Gulf of 
Tehuantepec. This gyre is strictly a winter 
phenomenon and ceases as soon as the winds 
in the Gulf of Tehuantepec change their 
direction. 
In July (Fig. 11) a current flows north along 
the coast of Mexico and enters the Gulf of 
California. The entire current pattern east of 
110°W is characterized by a slowly west to 
northwest moving water mass. West of this 
longitude the current is toward the south 
north of latitude 20°N and toward the west 
south of this latitude. 
The monthly average speeds of these cur- 
rents are low and lie almost entirely within 
5 cm/sec and 20 cm/sec. 
FRONTS IN THE VICINITY OF THE GULF 
In the following the term "front” will be 
used as suggested by Cromwell and Reid 
(1956), i.e., as a narrow band along the sea 
surface across which the density changes 
abruptly. The terms "temperature front” and 
"salinity front” will be used to describe the 
density front, since it is only from tempera- 
ture and salinity measurements that the dens- 
ity can be adequately determined. The definite 
character of a front can only be established 
if continuous temperature and salinity records 
are available. Unfortunately there are no con- 
tinuous records of salinity, for which reason 
a description of the fronts in the vicinity of 
the Gulf must be based on closely .paced 
stations rather than upon continuous records. 
Two regions of rapid temperature and salin- 
ity transition have been found to exist in the 
Gulf Entrance, one off Cabo San Lucas and 
one off Cabo Corrientes (Fig. 12). The San 
