Measurements of oceanic boundary currents for integral quantities such as heat and freshwater transports are very important for studying their long-term impacts on the global climate. There are a variety of boundary currents, including surface, intermediate and deep boundary currents on both the western and eastern sides of ocean basins. The dynamics and physics of these boundary currents are different, as are the ways of monitoring them. Here, we choose to explore the strategies adopted for observing four representative boundary current systems which have been the subject of detailed studies in recent years: the Kuroshio; the East Australian Current; the Indonesian Throughflow; and the low-latitude boundary current System of the Atlantic.
The transport of the Kuroshio south of Japan has been monitored using satellite altimeter
data in conjunction with an empirical relation between the transport and sea surface height
difference across the stream. Monitoring the transport of the East Australian Current has
been achieved by repeated high-resolution expendable bathythermograph (XBT) and/or
conductivity-temperature-depth profiler transects maintained at several locations, supplemented with satellite altimeter data. Repeated XBT transects have also been used to monitor transport of the Indonesian Throughflow, in association with current meter and other instrumental estimations of transport through a few major throughflow straits. Finally, the
complicated flow field of the low-latitude boundary current system of the Atlantic has been
revealed using neutrally buoyant floats, moored current meters and hydrographic observations.
The survey will be continued using further advanced observation technologies
