204
UWE SEND
3. Conclusions
An overview of the most widely used or most promising in-situ
observing techniques for operational applications has been provided. The
main intention was to emphasize the differences in terms of sampling and
capabilities, in order to give appreciation of the complementarity of the
approaches. No one method can usually fulfil the observational needs of any
operational (or science) application. Table 1 is meant to summarize the main
characteristics of the platforms discussed, and to help in guiding to the most
appropriate choice of observing means for specific observational
requirements. More importantly, however, it is meant to emphasize the
complementarity between all these elements and technologies which exist.
It is clear that many observing techniques had to be omitted here.
Acoustically tracked floats, electromagnetic methods to sense currents, or
inverted echosounders are some of them. They are not, however, used
operationally and there seems to be no plan at present to include them in
operational systems.
To highlight the sampling and complementarity in space and time, Figure
1 at the beginning of this chapter summarized the spatial and temporal
resolution and coverage of the observing methods discussed. While the
figure does not do justice to various methods by omitting the depth
dimension (where satellites would just provide a single horizontal
layer/slice), it is helpful to think in terms of this horizontal and temporal
sampling. There seems to be a gap on scales of 10 m - 1 km and on short
timescales, but most processes of interest to operational oceanography can
be observed with suitable combinations of existing methods.
One aspect that was not addressed above is that of data delivery.
Operational systems require in-situ data with minimal delay, usually within
one day. Some approaches inherently have a built-in data telemetry
capability, like drifters, floats, and gliders. Coastal radars and vessels just
need to be equipped with the required transmission systems, which is no
problem in principle. For moored or bottom-mounted instruments, and even
more so under the ice, data telemetry is not easy. Either seafloor cables need
to be available, or surface buoys are required, or telemetry packages that
occasionally come to the surface need to be attached to moorings. All these
exist or are under development.
The challenge in collecting data for operational applications is to
combine the available methods in the most efficient way, in order to provide
the observing system – together with remote sensing – that really samples all
four dimensions and the variables of interest such that models can make
maximum use of them.
UWE SEND
3. Conclusions
An overview of the most widely used or most promising in-situ
observing techniques for operational applications has been provided. The
main intention was to emphasize the differences in terms of sampling and
capabilities, in order to give appreciation of the complementarity of the
approaches. No one method can usually fulfil the observational needs of any
operational (or science) application. Table 1 is meant to summarize the main
characteristics of the platforms discussed, and to help in guiding to the most
appropriate choice of observing means for specific observational
requirements. More importantly, however, it is meant to emphasize the
complementarity between all these elements and technologies which exist.
It is clear that many observing techniques had to be omitted here.
Acoustically tracked floats, electromagnetic methods to sense currents, or
inverted echosounders are some of them. They are not, however, used
operationally and there seems to be no plan at present to include them in
operational systems.
To highlight the sampling and complementarity in space and time, Figure
1 at the beginning of this chapter summarized the spatial and temporal
resolution and coverage of the observing methods discussed. While the
figure does not do justice to various methods by omitting the depth
dimension (where satellites would just provide a single horizontal
layer/slice), it is helpful to think in terms of this horizontal and temporal
sampling. There seems to be a gap on scales of 10 m - 1 km and on short
timescales, but most processes of interest to operational oceanography can
be observed with suitable combinations of existing methods.
One aspect that was not addressed above is that of data delivery.
Operational systems require in-situ data with minimal delay, usually within
one day. Some approaches inherently have a built-in data telemetry
capability, like drifters, floats, and gliders. Coastal radars and vessels just
need to be equipped with the required transmission systems, which is no
problem in principle. For moored or bottom-mounted instruments, and even
more so under the ice, data telemetry is not easy. Either seafloor cables need
to be available, or surface buoys are required, or telemetry packages that
occasionally come to the surface need to be attached to moorings. All these
exist or are under development.
The challenge in collecting data for operational applications is to
combine the available methods in the most efficient way, in order to provide
the observing system – together with remote sensing – that really samples all
four dimensions and the variables of interest such that models can make
maximum use of them.