These were chosen at mid-latitudes where heat
flux is expected to be greatest, for example at
about 30°S in the southern hemisphere basins.
Apart from requiring temperature and salinity
measurements, the conclusions from such calculations are strongly dependent on the estimates of
current in the boundary regions, where columnaveraged properties (especially temperature)
depart significantly from section-mean properties.
It was intended that the heat flux lines would be
supported by current meter arrays in the boundary
currents. This strategy of hydrography coupled
with boundary current arrays was only partially
implemented: the lack of a complete trans-Indian
section at 30°S during the WOCE period was a
notable omission. Heavy reliance is still being
placed on the 1987 pre-WOCE section described
by Toole and Warren (1993). In the Pacific, the
30°N line (WOCE P2) was occupied in a number
of segments, at various degrees of resolution, in
1993 and 1994. The nearest single section is the
24°N line completed in two legs on RV Thomas
Thompson by Swift and Roemmich in 1985.
3.1.2.2 The achievements of the one-time
survey in WOCE
The global array of sections designed by the WHP
Planning Committee (WCRP, 1988a) contained
64 sections proposed for single occupation, but
excluded the Arctic and ice-covered Southern
Oceans. The principal justification for the exclusion of the high latitudes was that the design of
WOCE was linked to the availability of satellite
altimeter data. The TOPEX/POSEIDON ground
track turns at a latitude of 66°, although ERS-1
and ERS-2 turn at 82°. Practical considerations of
the resources required for high-latitude work also
played a part, and, further, the Arctic was the
subject of another WCRP programme: the Arctic
Climate System Study (ACSYS).
Figure 3.1.4 (see Plate 3.1.4, p. 172) shows the
location of one-time stations reported to the WHP
Office. The figure shows the unprecedented global
nature of the sampling in the WHP, as well as some
of the ‘holes’ in the survey. Some of the holes in the
Pacific and Indian basins are considered to have
been filled with high-quality pre-WOCE data from
the late 1980s; these are included in Figure 3.1.4
(see Plate 3.1.4, p. 172). But gaps remain where no
suitable data are available, such as a meridional
line at about 50°E in the Southwest Indian Ocean.
In June 2000 the WHP Office (D. Muus,
personal communication) had received details of
9215 one-time stations, which exceeds the number
originally planned. All stations shown in the figure
include CTD and bottle temperature, salinity, oxygen and nutrients; CFCs would have been measured
on most stations. Not all will have
3
H,
3
He,
14
C or
other tracers. Many stations also have CO 2 parameters (tCO 2 (total dissolved inorganic carbon), pCO 2
(partial pressure of CO 2 in the atmosphere), pH,
total alkalinity). A map showing distribution of
CO 2 measurements can be found in Chapter 6.3. At
the time of writing, a count of the exact number of
stations on which each parameter was measured is
not available, because not all tracer data have been
reported to the WHP Office. Figure 3.1.5 shows the
percentage of one-time cruises for which the WHP
Office has been notified that a tracer was measured.
For the more costly shore-based analyses, PIs are
likely to have sampled a subset of the stations completed during the cruise.
In early 2000, the WHP Office online listings
included 101 one-time cruises completed, of which
all but one had at least the CTD temperature and
salinity data submitted, and only one cruise was
listed as not having bottle salinity, oxygen and
nutrient data submitted to the Office. Tracers
requiring shore-based laboratory analysis take
longer to reach the Data Assembly Centre. (The
WHP Office, described in Section 3.1.2.4, is the
WOCE Data Assembly Centre for hydrographic
data.)
3.1.2.3 Variability and repeat hydrography
Temporal variability is the major issue for WOCE
Goal 2: determining the representativeness of
WOCE data and its usefulness as a baseline for
determining long-term changes. It is also a problem when combining one-time sections that are
not strictly synoptic. The water mass or property
transport budget for an enclosed region, for example, can be expected to balance only to the extent
that all sections bounding the box are sampling the
same flow and property fields; temporal changes
from one part of the survey to another must be
small compared with the average signal.
A total of 51 sections or geographical areas were
identified for which repeat observations were desirable or likely to happen anyway. It was expected
that these would produce 15 000 stations. By late
1999 the WHP Office was aware of or had received
3.1 Shipboard Observations during WOCE
105
King, Firing and Joyce
flux is expected to be greatest, for example at
about 30°S in the southern hemisphere basins.
Apart from requiring temperature and salinity
measurements, the conclusions from such calculations are strongly dependent on the estimates of
current in the boundary regions, where columnaveraged properties (especially temperature)
depart significantly from section-mean properties.
It was intended that the heat flux lines would be
supported by current meter arrays in the boundary
currents. This strategy of hydrography coupled
with boundary current arrays was only partially
implemented: the lack of a complete trans-Indian
section at 30°S during the WOCE period was a
notable omission. Heavy reliance is still being
placed on the 1987 pre-WOCE section described
by Toole and Warren (1993). In the Pacific, the
30°N line (WOCE P2) was occupied in a number
of segments, at various degrees of resolution, in
1993 and 1994. The nearest single section is the
24°N line completed in two legs on RV Thomas
Thompson by Swift and Roemmich in 1985.
3.1.2.2 The achievements of the one-time
survey in WOCE
The global array of sections designed by the WHP
Planning Committee (WCRP, 1988a) contained
64 sections proposed for single occupation, but
excluded the Arctic and ice-covered Southern
Oceans. The principal justification for the exclusion of the high latitudes was that the design of
WOCE was linked to the availability of satellite
altimeter data. The TOPEX/POSEIDON ground
track turns at a latitude of 66°, although ERS-1
and ERS-2 turn at 82°. Practical considerations of
the resources required for high-latitude work also
played a part, and, further, the Arctic was the
subject of another WCRP programme: the Arctic
Climate System Study (ACSYS).
Figure 3.1.4 (see Plate 3.1.4, p. 172) shows the
location of one-time stations reported to the WHP
Office. The figure shows the unprecedented global
nature of the sampling in the WHP, as well as some
of the ‘holes’ in the survey. Some of the holes in the
Pacific and Indian basins are considered to have
been filled with high-quality pre-WOCE data from
the late 1980s; these are included in Figure 3.1.4
(see Plate 3.1.4, p. 172). But gaps remain where no
suitable data are available, such as a meridional
line at about 50°E in the Southwest Indian Ocean.
In June 2000 the WHP Office (D. Muus,
personal communication) had received details of
9215 one-time stations, which exceeds the number
originally planned. All stations shown in the figure
include CTD and bottle temperature, salinity, oxygen and nutrients; CFCs would have been measured
on most stations. Not all will have
3
H,
3
He,
14
C or
other tracers. Many stations also have CO 2 parameters (tCO 2 (total dissolved inorganic carbon), pCO 2
(partial pressure of CO 2 in the atmosphere), pH,
total alkalinity). A map showing distribution of
CO 2 measurements can be found in Chapter 6.3. At
the time of writing, a count of the exact number of
stations on which each parameter was measured is
not available, because not all tracer data have been
reported to the WHP Office. Figure 3.1.5 shows the
percentage of one-time cruises for which the WHP
Office has been notified that a tracer was measured.
For the more costly shore-based analyses, PIs are
likely to have sampled a subset of the stations completed during the cruise.
In early 2000, the WHP Office online listings
included 101 one-time cruises completed, of which
all but one had at least the CTD temperature and
salinity data submitted, and only one cruise was
listed as not having bottle salinity, oxygen and
nutrient data submitted to the Office. Tracers
requiring shore-based laboratory analysis take
longer to reach the Data Assembly Centre. (The
WHP Office, described in Section 3.1.2.4, is the
WOCE Data Assembly Centre for hydrographic
data.)
3.1.2.3 Variability and repeat hydrography
Temporal variability is the major issue for WOCE
Goal 2: determining the representativeness of
WOCE data and its usefulness as a baseline for
determining long-term changes. It is also a problem when combining one-time sections that are
not strictly synoptic. The water mass or property
transport budget for an enclosed region, for example, can be expected to balance only to the extent
that all sections bounding the box are sampling the
same flow and property fields; temporal changes
from one part of the survey to another must be
small compared with the average signal.
A total of 51 sections or geographical areas were
identified for which repeat observations were desirable or likely to happen anyway. It was expected
that these would produce 15 000 stations. By late
1999 the WHP Office was aware of or had received
3.1 Shipboard Observations during WOCE
105
King, Firing and Joyce