Vertical Structure of the Abyssal Circulation
445
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Fig. 7.7.2a,b. Response of the abyssal flow as shown in the meridional velocity profile to an
integrated source function S(z). S has the form. S0 [ 1- cos ( 2 "(Z:H))]. The constant Kin (7.7.44)
is adjusted to satisfy the overall mass balance. b,c Meridional velocity profiles at different x
locations across the basin. Solid vertical line, zero for dotted line, meridional velocity profile. The
variable x is scaled with L while v is scaled with f K L / (3H. b meridonal velocity profiles for the case
where the upwelling is spatially uniform (t = s = 0). c The meridional velocity profiles for the case
where there is a strong variation of the upwelling velocity in the zonal direction, s(xe- xw) = 2
become nearly zero at the upper boundary. Thus there is vortex tube
compression near the upper surface in the western region which drives an
equatorward flow according to (7. 7.1 ). At mid depth the effect of the source is
again important, and the flow is poleward. As discussed above, since w0 is
essentially zero in the west when sL is sizable, the meridional velocity must very
nearly have a zero vertical average, i.e., it must be layered. In Fig. 7.7.2c the
dashed-dot line shows the magnitude of the barotropic component of the
meridional velocity. It decays westward, of course, in the same way as does w0 .
At almost all locations the baroclinic velocity far exceeds the barotropic
445
.-~--~----,---~~--,---~-----r--~~---r--~~---r~nH
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0.2
0.4
0.6
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1
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Fig. 7.7.2a,b. Response of the abyssal flow as shown in the meridional velocity profile to an
integrated source function S(z). S has the form. S0 [ 1- cos ( 2 "(Z:H))]. The constant Kin (7.7.44)
is adjusted to satisfy the overall mass balance. b,c Meridional velocity profiles at different x
locations across the basin. Solid vertical line, zero for dotted line, meridional velocity profile. The
variable x is scaled with L while v is scaled with f K L / (3H. b meridonal velocity profiles for the case
where the upwelling is spatially uniform (t = s = 0). c The meridional velocity profiles for the case
where there is a strong variation of the upwelling velocity in the zonal direction, s(xe- xw) = 2
become nearly zero at the upper boundary. Thus there is vortex tube
compression near the upper surface in the western region which drives an
equatorward flow according to (7. 7.1 ). At mid depth the effect of the source is
again important, and the flow is poleward. As discussed above, since w0 is
essentially zero in the west when sL is sizable, the meridional velocity must very
nearly have a zero vertical average, i.e., it must be layered. In Fig. 7.7.2c the
dashed-dot line shows the magnitude of the barotropic component of the
meridional velocity. It decays westward, of course, in the same way as does w0 .
At almost all locations the baroclinic velocity far exceeds the barotropic