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+1.3 m
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Fig. 6.24
The remarkable satellite-measured topography of the mean sea surface (with wave and tidal wave effects subtracted).
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GS
KS
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AC
AC
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Fig. 6.25
The major pattern of gradient flow from the computed dynamic sea surface. Note the control of current vectors (both magnitude
and direction) by the magnitude of the spatial gradients in water topography, that is, OBL flow is parallel to the gradient lines, with an inten-
sity proportional to grayscale thickness. Note western intensification of Pacific Kuroshio (KS) and Atlantic Gulf Stream (GS) currents and the
strong circumpolar Antarctic current (AC).
though complex, meandering filament of warm Caribbean
water in transit to the shores of northwest Europe
(Figs 6.26 and 6.27). In the mid-twentieth century,
Stommel explained these most striking features of the
general oceanic circulation by a consideration of both
lateral friction and conservation of angular momentum.
We have seen that all moving fluid masses possess
vorticity appropriate to the latitude in which they find
themselves (Section 3.8) and that the total, or absolute, vor-
ticity (
f
) must be conserved. Thus a northward-moving
mass of water, impelled by wind shear to spin clockwise, will
gain planetary vorticity as it moves. In order to keep
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