Figure 2 shows the surface temperature over the shelf. There is seen to be some increase of temperature towards the northwest along the Guatemalan coast. The Champerico section (see Figure 3) demonstrate that the sharp discontinuity layer in temperature, salinity and oxygen is now found at a depth of 30 - abt. 70 m which is considerably shallower than in March and June.
The sea surface temperature in the Tehuantepec Gulf shows with 31°C in inshore waters probably a seasonal maximum. There is no trend in the north of a decrease shorewards as in March reflecting the absence at this time of northerly winds. The San Marcos profile (Figure 3) shows at this season no sign of the offshore dome prominant in the observations during the March survey. Nor is there any tendency of the transition layer in the Salina Cruz profile to lift shorewards as in June.
