Equatorial ocean circulation
269
Summary
Interesting features of the equatorial ocean circulation are the Equatorial Counter Currents (ECCs) and Equatorial Under Currents (EUCs).
A reduced gravity model is a two-layer model in which the lower layer
is motionless.
Equatorial Counter Currents exist because of the weakening of the
trade winds slightly north of the equator leading to a negative meridional gradient in the sea surface height.
Long baroclinic waves in the equatorial wave guide consist of Kelvin
waves (with phase speed c 0 =
√
g ′ H) and Rossby waves with phase
speeds
c j∗ = −
c 0
2j +1
where j is associated with the meridional structure of the wave. The
travel time of the Kelvin wave over the Pacific is about 3 months (with
c 0 =2ms −1 ) and this is 9 months for the j =1Rossby wave.
The response of an equatorial ocean basin to a wind-stress field can be
determined using Green’s function theory. The thermocline deviation
due to a zonal wind stress of 0.1 Pa is about 100 m.
269
Summary
Interesting features of the equatorial ocean circulation are the Equatorial Counter Currents (ECCs) and Equatorial Under Currents (EUCs).
A reduced gravity model is a two-layer model in which the lower layer
is motionless.
Equatorial Counter Currents exist because of the weakening of the
trade winds slightly north of the equator leading to a negative meridional gradient in the sea surface height.
Long baroclinic waves in the equatorial wave guide consist of Kelvin
waves (with phase speed c 0 =
√
g ′ H) and Rossby waves with phase
speeds
c j∗ = −
c 0
2j +1
where j is associated with the meridional structure of the wave. The
travel time of the Kelvin wave over the Pacific is about 3 months (with
c 0 =2ms −1 ) and this is 9 months for the j =1Rossby wave.
The response of an equatorial ocean basin to a wind-stress field can be
determined using Green’s function theory. The thermocline deviation
due to a zonal wind stress of 0.1 Pa is about 100 m.