the line of the section takes place in small time intervals of several days and it is
localized in relatively small parts of this section, where the largest non-stationarity
has been noted. Thus, in the analysis of the real field data in the ocean, the estimates
of such distortions are absolutely necessary both with respect to the calculation of
the total transport across the section, and with respect to the investigation of the
structure of this transport. This conclusion concerns even such “fast” measurements
as sections in the Drake Passage, the duration of which is less than 10 days.
As can be seen from Table 2, the range of variability of the instantaneous
barotropic transports (the range of barotropic transport anomaly values in Table 2)
over most sections is significant compared with the FBTE ⟨δQ⟩; the exception is
related to almost all “quick” sections in the Drake Passage (except for SR01 in
2016) and four SR03 sections south of Australia (1994, 1995, 1996, and 2011).
These facts of such significance indicate that the estimation of the variability of the
barotropic transport caused by the displacement of streamlines at the ocean surface
relative to the isobaths is essential in the analysis of the field data, even over “fast”
sections. For example, the duration of the above mentioned SR01 section in 2016
was only 6 days.
The range of instantaneous barotropic transport variability should be interpreted
depending on the restrictions on the total transport across the section. Under the
conditions of constant total transport across the section line, the oscillations of its
baroclinic and barotropic components must completely compensate each other. It is
exactly the case that is observed over the lines of the transoceanic quasi-zonal
sections crossing the Atlantic, Indian, and Pacific oceans. In the Atlantic Ocean,
instantaneous total transport corresponds to the inflow of the Pacific waters through
the Bering Strait; in the Indian Ocean this is the inflow through the Indonesian
straits (over the sections from Africa to Australia); in the Pacific Ocean this is a
combination of the outflow through the Indonesian straits depending on the location
of the section. Thus, the range of the barotropic transport anomaly values ΔQ
′
alt t
ð Þ
in Table 2 for the corresponding sections also gives an indirect estimate of the
oscillations of baroclinic transports.
The time variability of the total transport over the quasi-meridian sections
crossing the Southern Ocean exists, due to the variability of the transport of the
ACC, as a result of which exact compensation of the oscillations of the instantaneous
barotropic transport by the baroclinic apparently does not occur. At the same time,
the measurements in the Drake Passage [8] show a high degree of anticorrelation
between the barotropic and baroclinic transports in the Southern Ocean. Under these
conditions, the range of the barotropic transport anomaly values ΔQ
′
alt t
ð Þ in Table 2
represents an indirect combined estimate of fluctuations in the baroclinic transport
and the variability of the total transport. We also note that no exact compensation
occurs over the lines of the sections not ending at the continental slope.
The account for Q t allows us to complete the total transport, determined from the
data of the instant ADCP measurements over a section, to such a total transport that
has exact physical correspondence between its baroclinic and barotropic components. This is caused by the gained exact time correspondence between the ocean
394
R. Yu. Tarakanov
localized in relatively small parts of this section, where the largest non-stationarity
has been noted. Thus, in the analysis of the real field data in the ocean, the estimates
of such distortions are absolutely necessary both with respect to the calculation of
the total transport across the section, and with respect to the investigation of the
structure of this transport. This conclusion concerns even such “fast” measurements
as sections in the Drake Passage, the duration of which is less than 10 days.
As can be seen from Table 2, the range of variability of the instantaneous
barotropic transports (the range of barotropic transport anomaly values in Table 2)
over most sections is significant compared with the FBTE ⟨δQ⟩; the exception is
related to almost all “quick” sections in the Drake Passage (except for SR01 in
2016) and four SR03 sections south of Australia (1994, 1995, 1996, and 2011).
These facts of such significance indicate that the estimation of the variability of the
barotropic transport caused by the displacement of streamlines at the ocean surface
relative to the isobaths is essential in the analysis of the field data, even over “fast”
sections. For example, the duration of the above mentioned SR01 section in 2016
was only 6 days.
The range of instantaneous barotropic transport variability should be interpreted
depending on the restrictions on the total transport across the section. Under the
conditions of constant total transport across the section line, the oscillations of its
baroclinic and barotropic components must completely compensate each other. It is
exactly the case that is observed over the lines of the transoceanic quasi-zonal
sections crossing the Atlantic, Indian, and Pacific oceans. In the Atlantic Ocean,
instantaneous total transport corresponds to the inflow of the Pacific waters through
the Bering Strait; in the Indian Ocean this is the inflow through the Indonesian
straits (over the sections from Africa to Australia); in the Pacific Ocean this is a
combination of the outflow through the Indonesian straits depending on the location
of the section. Thus, the range of the barotropic transport anomaly values ΔQ
′
alt t
ð Þ
in Table 2 for the corresponding sections also gives an indirect estimate of the
oscillations of baroclinic transports.
The time variability of the total transport over the quasi-meridian sections
crossing the Southern Ocean exists, due to the variability of the transport of the
ACC, as a result of which exact compensation of the oscillations of the instantaneous
barotropic transport by the baroclinic apparently does not occur. At the same time,
the measurements in the Drake Passage [8] show a high degree of anticorrelation
between the barotropic and baroclinic transports in the Southern Ocean. Under these
conditions, the range of the barotropic transport anomaly values ΔQ
′
alt t
ð Þ in Table 2
represents an indirect combined estimate of fluctuations in the baroclinic transport
and the variability of the total transport. We also note that no exact compensation
occurs over the lines of the sections not ending at the continental slope.
The account for Q t allows us to complete the total transport, determined from the
data of the instant ADCP measurements over a section, to such a total transport that
has exact physical correspondence between its baroclinic and barotropic components. This is caused by the gained exact time correspondence between the ocean
394
R. Yu. Tarakanov