324
Equatorial Dynamics of the Thermocline: The Equatorial Undercurrent
surements, shown in Fig. 6.1.2, with the geostrophic measurements of the
preceding figure. The agreement is very good indeed.
The current structure in the equatorial Atlantic is very similar. Figure 6.1.3 shows the temperature and velocity and temperature profiles in the
Atlantic at 28°W and the Pacific at 140°W. The similarity is striking.
Figures of latitude-depth cross sections emphasize the two-dimensional
structure of the current in the meridional plane. The flow, however, is threedimensional. The equatorial thermocline, just as the thermocline in midlatitudes, slopes strongly upward to the east and the EUC, which is embedded
U. PCt..t
s:.
l
b
Fig. 6.1.2. a Contours of zonal velocity in the EUC measured directly with a profiling Doppler
current meter in the Pacific at the same longitude as Fig. 6.1.1. Note the excellent agreement
between the actual and geostrophic velocities. b The density field measured in the same section.
Note that the meridional density gradient vanishes at the equator. (From Johnson and Luther
1994)
Equatorial Dynamics of the Thermocline: The Equatorial Undercurrent
surements, shown in Fig. 6.1.2, with the geostrophic measurements of the
preceding figure. The agreement is very good indeed.
The current structure in the equatorial Atlantic is very similar. Figure 6.1.3 shows the temperature and velocity and temperature profiles in the
Atlantic at 28°W and the Pacific at 140°W. The similarity is striking.
Figures of latitude-depth cross sections emphasize the two-dimensional
structure of the current in the meridional plane. The flow, however, is threedimensional. The equatorial thermocline, just as the thermocline in midlatitudes, slopes strongly upward to the east and the EUC, which is embedded
U. PCt..t
s:.
l
b
Fig. 6.1.2. a Contours of zonal velocity in the EUC measured directly with a profiling Doppler
current meter in the Pacific at the same longitude as Fig. 6.1.1. Note the excellent agreement
between the actual and geostrophic velocities. b The density field measured in the same section.
Note that the meridional density gradient vanishes at the equator. (From Johnson and Luther
1994)