Conducting Marine Science in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 226

phytoplankton. The same satellite provides global maps of sea surface temperature, while
NASA's Aquarius mission has been doing the same for surface salinity. Aquarius also car-
ries the Advanced Microwave Scanning Radiometer (AMSR), which can measure differ-
ences in microwaves emitted from sea ice and water to provide maps of ice concentration.
The technological revolution is not just confined to space. It is also in and on the
water. Probably the best-known example of an ocean-going sampling system is the Argo
programme. Since 2004, 3,500 free-drifting Argo floats have been measuring temperature,
pressure and salinity. They do so as they slowly rise and sink over a 10-day cycle. When at
the surface, they send a package of data to an orbiting satellite. The Argo “fleet” collects
about 120,000 vertical profiles a year! The next generation of Argo floats will even have
the capacity to measure phytoplankton primary production.
A somewhat related development has been the use of “gliders”. These resemble a fat
surfboard with several antennae and sensors on top. They can move following directions
given by an operator ashore and many have no fuel requirements. Power comes from a set
of solar cells attached to the upper surface and from wave energy. A payload of sensors
is carried mainly on the lower surface. They can measure, for example, sea surface tem-
perature and salinity at subsurface depths just beneath the level that is “sampled” by or-
biting satellites. Data are again downloaded to a passing satellite. Today, these platforms
frequently work in association with satellites equipped to measure sea temperature and sa-
linity in studies designed to investigate the global water cycle and its linkages to climate
change.
Of course, ship-based observations remain essential, particularly in the Arctic, but the
previous examples will have given a taste of the exciting opportunities that now exist. In
practice, the new autonomous systems (such as gliders) often work together with a ship-
based programme.
To sum it all up, if Fridtjof Nansen (from the third Fram expedition to the Arctic
between1893and1896)couldhavebeentransportedthroughtimetojoinusinDavisStrait
in 1977, he would have been thoroughly familiar with a good deal of our equipment. This
included the reversing thermometers. After all, he designed the water-sampling bottle we