Marine Ecosystems Research Department - jamstec japan agency ...

JAMSTEC 2002 Annual Report
Ocean Observation and Research Department
flux from the warm Atlantic Layer, we could find differences
of the water properties among the above three
regions. The differences suggest that the water in the
Nansen Basin received an effect of stronger winter
mixing than that in the Amundsen Basin. The differences
of water characteristics also suggest that the origins
of the upper water in the Amundsen Basin, over
the Arctic Mid Ocean Ridge, and in the Nansen Basin
would be the Kara Sea, the western side of the Laptev
Sea, and the eastern side of Laptev Sea (or the East
Siberian Sea), respectively.
To understand interannual variability of water mass
characteristics in the eastern Arctic Ocean, we have
examined their distributions since using the data
observed by ice-drifting buoys, icebreaker cruises,
submarine cruises, airborne hydrographic survey and
so on. Figure is one of the results in the research on
interannual variability and shows a distribution of
salinity at m depth in the early s (-).
The data of Fig. were observed by J-CAD and
NPEO hydrographic CTD survey. One of the topics of
Arctic oceanographers is surface salinization in the
84N
Eastern Arctic Ocean that would be strongly associated
with a retreat of the Cold halocline. Our results
present that such surface salinization in the Amundsen
Basin was first found in the Siberian side over the
Lomonosov Ridge, and extended its area toward the
entire Amundsen Basin in the mid and late s. The
higher salinity anomaly was still found in the central
Amundsen Basin and over the Arctic Mid Ocean
Ridge. This condition would prevent sea ice formation
due to the deepening of the winter mixed layer. On the
other hand, the anomaly was weakening over the
Lomonosov Ridge in the early s.
Theme 4: Research on chemical environment and
its changes in the ocean
() Development of at-sea chemical analysis technology
We intend to develop a new instrument for detecting
changes of chemical environment in the ocean. We
collected information to designate an automatic instrument
for the analysis of CO related species. The pCO
profiler was presented in Techno-Ocean , Osaka.
It was developed under our suggestion.
An analytical instrument to measure the dissolved
oxygen content in seawater was developed and used
in field observation. It was found that the instrument
was useful to measure large numbers of dissolved
oxygen samples.
90W
0
31.0 32.0 33.0 34.0 35.0
Fig.14 Distribution of salinity at 25m depth observed by J-CAD
and NPEO hydrographic survey. Background colors show
the EWG winter climatological (1948-93) data.
() Observational study for chemical environment and
its changes in the ocean
(a) During the Mirai cruise of MR-K, we conducted
observation at E from N to N at an
interval of degree and at some stations in the northern
part of the northwestern North Pacific where we
carried out observation in the past. On board, we
measured water temperature, salinity, oxygen, nutrients,
total CO (TCO ), pH, total alkalinity, trace metals,
and CFCs. Additionally, temperature, salinity, fluorescence,
pCO , and TCO in surface seawater were
measured continuously along the cruise track. Figure
shows distributions of anthropogenic CO and
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