Study of Ocean Circulation since 1935
171
alter transports in the various layers. That is, the middepth and deep oceans are also
variable, and this includes large-scale flow. The time scales are fast enough to disrupt
our simple schemes of steady-state geostrophic transport. The vertical shear is not
constant over time, even in the deep waters.
ISOPYCNALS
Examination of patterns of characteristics along isopycnals that were first explored
by Parr (1935) and Montgomery (1938) in the Atlantic has expanded since the 1950s
and especially since the 1970s, when computers became available.
Ivers’s (1975) study of the northern North Atlantic used what he called neutral
surfaces. These have been developed further by McDougall (1987) and several other
approaches have been suggested.
Reid (1994, 1997, 2003) has used the approximation suggested by Lynn and
Reid (1968) in various large-scale studies in all three oceans. Large-scale investigations in all three oceans have involved some sort of isopycnal analysis.
Lozier et al. (1995) used patterns along isopycnal surfaces to prepare a climatologic atlas of the North Atlantic. With the vast amount of newer data and the
interpolation along isopycnals it is much more complete than the earlier atlas of
Levitus (1982), which averaged along isobaths, and gives a generally clearer picture. This and the study of Iorga and Lozier (1999a,b) show both the northward and
westward extensions of the Mediterranean outflow.
Tsuchiya (1968) used isopycnals and relative geostrophic flow to map the upper
circulation of the intertropical Pacific and (1989) the circulation of the Antarctic
Intermediate Water in the North Atlantic.
Masuzawa (1972) used isopycnal patterns and relative geostrophic flow in a
study of the North Pacific Ocean that dealt with the extension of the Kuroshio Current.
Mantyla and Reid (1995) displayed the deep tracers in the Indian Ocean and
Reid (2003) added the adjusted geostrophic flow.
You et al. (2000) have made extensive use of the patterns of isopycnals in such
studies as the North Pacific Intermediate Water and in the Atlantic–Indian Ocean
exchange south of Africa (You et al., 2003).
INTERMEDIATE WATER
Although the subsurface salinity minimum in the North Pacific Ocean had been apparent since the Challenger expedition, they had been supposed to derive from sinking of
the low-salinity surface water of the far north (Uda, 1935; Sverdrup et al., 1942). Later,
Reid (1965) proposed that as water of the density of the salinity minimum had not
been found at the sea surface in the North Pacific, the subsurface minimum there must
occur by diffusion downward from the surface in the north and a subsurface lateral
171
alter transports in the various layers. That is, the middepth and deep oceans are also
variable, and this includes large-scale flow. The time scales are fast enough to disrupt
our simple schemes of steady-state geostrophic transport. The vertical shear is not
constant over time, even in the deep waters.
ISOPYCNALS
Examination of patterns of characteristics along isopycnals that were first explored
by Parr (1935) and Montgomery (1938) in the Atlantic has expanded since the 1950s
and especially since the 1970s, when computers became available.
Ivers’s (1975) study of the northern North Atlantic used what he called neutral
surfaces. These have been developed further by McDougall (1987) and several other
approaches have been suggested.
Reid (1994, 1997, 2003) has used the approximation suggested by Lynn and
Reid (1968) in various large-scale studies in all three oceans. Large-scale investigations in all three oceans have involved some sort of isopycnal analysis.
Lozier et al. (1995) used patterns along isopycnal surfaces to prepare a climatologic atlas of the North Atlantic. With the vast amount of newer data and the
interpolation along isopycnals it is much more complete than the earlier atlas of
Levitus (1982), which averaged along isobaths, and gives a generally clearer picture. This and the study of Iorga and Lozier (1999a,b) show both the northward and
westward extensions of the Mediterranean outflow.
Tsuchiya (1968) used isopycnals and relative geostrophic flow to map the upper
circulation of the intertropical Pacific and (1989) the circulation of the Antarctic
Intermediate Water in the North Atlantic.
Masuzawa (1972) used isopycnal patterns and relative geostrophic flow in a
study of the North Pacific Ocean that dealt with the extension of the Kuroshio Current.
Mantyla and Reid (1995) displayed the deep tracers in the Indian Ocean and
Reid (2003) added the adjusted geostrophic flow.
You et al. (2000) have made extensive use of the patterns of isopycnals in such
studies as the North Pacific Intermediate Water and in the Atlantic–Indian Ocean
exchange south of Africa (You et al., 2003).
INTERMEDIATE WATER
Although the subsurface salinity minimum in the North Pacific Ocean had been apparent since the Challenger expedition, they had been supposed to derive from sinking of
the low-salinity surface water of the far north (Uda, 1935; Sverdrup et al., 1942). Later,
Reid (1965) proposed that as water of the density of the salinity minimum had not
been found at the sea surface in the North Pacific, the subsurface minimum there must
occur by diffusion downward from the surface in the north and a subsurface lateral