Summary of Research Cruise Research Vessel“MIRAI”during fiscal year 2009

Outline of Main Research Theme for
Research Vessel “MIRAI” during fiscal year 2009

1. Cruise Code :

MR09-04

2. Main research theme:

Tropical Ocean Climate study
Operation of TRITON buoy array

3. Objectives:

The most prominent phenomenon of the climate variations, which does not originate from anthropogenic greenhouse gases, among various documented climate variation modes in the globe, is the El Nino/Southern Oscillation in the tropical Pacific. Once this phenomenon is generated, various abnormal meteorological events occur simultaneously in the global scale, and its socio-economic impacts become large. It is reported that the 1997-98 El Nino caused impact on the socio-economic activities in the United States worth 20-30 billion dollars. El Nino primarily means the anomalous high temperature phenomena in the eastern tropical Pacific; however, many studies have indicated the various kinds of inherent processes from regional scale to basin scale, from far-western to far-eastern tropical Pacific and overlaying tropical atmosphere. In the western Pacific region, there exists “warm water pool”, characterized by highest sea surface temperature in the world, receiving and redistributing huge amount of solar energy, and the region is thought to be one of the important region for ocean climate research. In spite of our past observational efforts, because of complex processes governing El Nino, it has not been enough to understand major processes in and over the Pacific warm water pool.
In this challenge, for the purpose of better understanding of ocean-origin climate phenomena in the Pacific, by continuing longer-term ocean-atmosphere observation by TRITON surface buoy array in the western Pacific as well as using numerical model output, we aim to clarify,
- major processes governing each phases of El Nino phenomena in the tropical Pacific,
- roles of multi-scale interactions from diurnal to global warming time-scale to El Nino phenomena, and
- basic and fundamental physical oceanographic processes to better understand these climate variation modes.

4. Outline of observation:

Major missions are to recover and deploy the TRITON surface moorings and ADCP subsurface moorings. The six TRITON moorings along 156E will be recovered and deployed, and the three ones will be along 147E. The two ADCP moorings will be recovered and deployed, too. CTD measurements up to 1000m depth will be carried out around the mooring deployment sites.

Table 1 List of TRTION buoy to be maintained

Buoy site No.	Nominal position	Depth [ｍ]	Buoy type	remarks
1	8N156E	4843	TRITON	CTD, Surface met observation etc.
2	5N156E	3605	TRITON	CTD, Surface met observation etc.
3	2N156E	2573	TRITON	CTD, Surface met observation etc.
4	EQ156E	1956	TRITON	CTD, Surface met observation etc.
5	2S156E	1751	TRITON	CTD, Surface met observation etc.
6	5S156E	1523	TRITON	CTD, Surface met observation etc.
7	5N147E	4297	TRITON	CTD, Surface met observation etc.
8	2N147E	4493	TRITON	CTD, Surface met observation etc.
9	EQ147E	4472	TRITON	CTD, Surface met observation etc.

Table 2 List of subsurface ADCP moorings to be maintained

Nominal site	depth	Buoy type	sensors	remarks
0-147E	4485	Subsurface	ADCP
0-156E	1956	Subsurface	ADCP

5.Main research area:

Rectangular area surrounded by 8N-156E, 5S-156E, Eq-147E, and 5N-147E
TRITON mooring sites at 8N, 5N, 2N, Eq, 2S, 5S along 156E and 5N, 2N, Eq along 147E will be maintained, and ADCP mooring sites at Eq-156E and Eq-147E will be maintained.

6.Cruise period:

From November 4,2009 to December 12,2009 (39days)

7.Ports of call (tentative):

Port of departure:	Sekinehama (Japan)
Port of call :	Hachinohe (Japan)

8.Proponent of main research theme:

Kentaro Ando
Climate Variations Observational Research Program/IORGC

Yasuhisa Ishihara
Department of Applied Ocean Enginnering

9. Contact person for questionnaire on this cruise:

Kentaro Ando
Institute of Observational Research for Global Change
Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
Phone: +81-46-867-9462, Fax: +81-46-867-9835, E-mail:

10. Remarks :

For the research themes publically applied for this cruise, in addition to the usual observation/research on board of the MIRAI, they could also install new sensors on the TRITON buoys. For the details such as payload, method and capacity of installing the additional sensors on the buoy platform, please contact the proponents prior to the application.

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