2007 Annual Report - jamstec japan agency for marine-earth ...

Chapter 2. Results of FY2007 Activities
I. Measures to be taken to achieve the objectives for
improving the quality of services and other operations
provided to the public
1 Fundamental research and development concerning
ocean science and technology
1.1 Promotion of key research activities
1.1.1 Observational Research for Global Change
(1) Climate Variations Observational Research
Program
The objective of the Climate Variations Observational
Research Program is to develop an extensive and continuous
ocean observing system in the Pacific and Indian Ocean, to
reveal the mechanisms of the variations in the upper layer with
annual to decadal time scales. The Tropical Ocean Climate
Group focuses mainly on the phenomena that occur in the warm
water pool of the western Pacific and the eastern Indian Ocean
while the Argo Group focuses mainly on interannual to decadal
variations in the north Pacific. In order to further facilitate
these research activities, under the cooperation with various
international organizations, we will continue to develop the
TRITON buoy mooring network in the equatorial Pacific and
the Indian Ocean as well as developing the Argo float array
with a focus on the mid-latitude regions of the both oceans.
Tropical Ocean Climate Group
Tropical Ocean Climate Group continued the observations
in the western tropical Pacific and the eastern tropical Indian
Ocean by using the TRITON buoy array and sub-surface ADCP
moorings. Two cruises in the western tropical Pacific and one
cruise in the east tropical Indian Ocean were conducted by R/V
MIRAI under the cooperation with the Marine Technology
Center of JAMSTEC. During these three cruises, total of 15
TRITON buoys in the western tropical Pacific were
recovered/deployed and 2 TRITON buoys in the east Indian
Ocean were recovered. Also starting this year, 2 m-TRITON
buoys funded directly by the Ministry of Education, Culture,
Sports, Science and Technology (MEXT) were deployed
replacing the TRITON buoys. The mooring location of the
TRITON/m-TRITON buoys and sub-surface ADCP buoys were
shown in Fig. 1.
XCTD/XBT observations in the northern Indian Ocean
were conducted by using the volunteer observation ships. The
data obtained by this observation is delivered to the meteorological
institutions in the world by GTS and is open to the public
after the quality control. Some of the major results of analyzing
these data obtained are introduced below.
a. Zonal gradient of sea surface temperature and variation of
Pacific warm pool associated with cooling in the western
Pacific before the onset of El Niño.
In order to clarify a role of interaction between the atmosphere
and the ocean over the warm pool in the western tropical
Pacific in the mechanism of onset of El Niño, upper ocean temperature
variation around warm pool region west from 156 o E
(hereafter, FWEP)where the TRITONN buoys were deployed
was investigated from boreal winter of 2001 to boreal spring of
2002 before the onset of the 2002/03 El Niño.
Satellite data indicates that negative sea surface temperature
anomalies are developed in the east coast of New Guinea before
the onset of the 2002/03 El Niño (December, 2001) to expand
eastward in a wide area of the western equatorial Pacific (Fig.
2). At this time the sea surface temperature in FWEP showed a
positive zonal gradient with enhancement of westerly wind
anomalies to start moving the Pacific warm pool eastward, followed
by the onset of the 2002/03 El Niño.
Fig. 1 Mooring location of the buoys as of January, 2008. Red and blue solid circles indicate the buoys by JAMSTEC and the empty white circle
indicates the Atlas buoys by NOAA of USA.
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