Zonal pressure gradient along the equatorial Atlantic

For three consecutive periods during the summer of 1974, ships of many nations made observations along the Atlantic equator as part of the GATE program [GARP (Global Atmospheric Research Program) Atlantic Tropical Experiment]. Combining these observations, it is found that the zonal pressure gradient over the central Atlantic at the surface and at 50 dbar, relative to 500 dbar, increased from 3.2 to 7.3 and 2.2 to 5.3 × 10-5 dynes/g respectively between June/July and August and then held close to the high values in September...

Meanders and Long Waves in the Equatorial Atlantic

Observations from the GATE Equatorial Oceanographic Experiment are presented. They reveal large scale meandering of the westward flowing South Equatorial Current and of the eastward flowing Equatorial Undercurrent with time scales of 2–3 weeks. Meandering of the flow pattern was found to be related to corresponding displacements of the high salinity core of the undercurrent. The observations tend to support the assumption of a long wave propagating westward with a phase speed of 2.3 m s−1 and a wavelength of 3,200 km. A possible explanation may be given in terms of unstable waves caused by large scale horizontal shear in the Equatorial Current System