Outline of Research Cruises for
Research Vessel "MIRAI" during fiscal year 2002
1. Cruise Code: MR02-K06
2. Main Research Themes :
Mission-A The Study of Air-Sea Interaction in the Tropics (Leg-1)
Mission-B Observational Studies in the Western Tropical Pacific Ocean (Leg-2)
Mission-C Biogeochemical and optical research in the Equatorial Pacific (Leg-2, 3, 4)
3. Objectives :
Mission-A (Leg-1)
The aim of the cruise is to obtain the various data especially focussing on precipitation to reveal the precipitation mechanism of the convections developed over the warm water pool in the tropical western Pacific region, where air-sea interaction is very active. The evaluation of the precipitation effect onto the ocean surface structure is also important theme of this study. Main target is an well-organized cloud cluster that is often observed during the active phase of the equatorial intraseasonal oscillation (Madden-Julian Oscillation).Mission-B (Leg-2)
For the purpose of understanding the role of the warm water pool to El Nino and Asian Monsoon,which affect the social and economical activities in the East Asian countries including Japan, we will conduct the observational studies on the oceanic and atmospheric variability. The major theme is to clarify the heat, freshwater and momentum balances in the surface mixed layer in the warm water pool in the western Pacific Ocean as well as the eastern Indian Ocean.Mission-C (Leg-2,3,4)
The western equatorial Pacific contains so-called warm water pool. Nitrate is depleted there and primary production is small. In the central and eastern equatorial Pacific, vertical flux of nutrients is enhanced due to Quasi-stationary upwelling caused by equatorial divergence and consequently chlorophyll a concentration and primary production rate increased along the equator. However, primary production and biomass are not as high as would be expected from the flux of nutrients could support. This is called high nutrient low chlorophyll situation. Since this east to west asymmetry is affected by ENSO event, there is a significant variability in physical characters on seasonal-interannual scale with impact to biogeochemistry, as well potentially with the similar scale of variability. In order to investigate the mechanism of this biogeochemical variability, we will conduct a biogeochemical observation cruise in the equatorial Pacific.
4. Outline of Observation :
Mission-A (Leg-1)
Stationary observation near (2N, 138E) will be conducted for most observation period in the leg-1. Continuous Doppler radar observation and the launch of radiosonde every 3 hours are the main observation items. In addition, CTD casting down to 1000m depth, shipboard ADCP, surface meteorological measurement, ceilometer observation will also be conducted routinely.Mission-B (Leg-2)
The major works are to deploy and recover surface moored TRITON buoys and subsurface moored ADCP buoys. The TRITON buoys will be deployed and recovered three along 147E and six along 156E in the western tropical Pacific Ocean. This cruise is focusing on obtaining oceanic and atmospheric physical parameters. CTD measurements will be carried out in the buoy deployment area with a water sampler which 12 sampling bottles of 12-litter down to 1000 m.Mission-C (Leg-2, 3)
We will make a comprehensive observation to investigate carbon cycle especially in a biological aspect. Our observation includes ;
- Hydrocast for physical, chemical and biological parameters such as salinity, nutrients, dissolved inorganic carbon, plant pigments and so on.
- Atmospheric and oceanic CO2 measurements.
- In situ and simulated in situ incubation for primary productivity and new productivity.
- Sediment trap moorings to observe export production.
- Distribution of phytoplankton and zooplankton.
- Etc.
5. Main Research Area :
Leg-1 135E_145E, 8N_2S (Stationary observation point is scheduled to be at 2N,138E.)
Leg-2 142E_156E,10N_5S (TRITON buoy sites are 156E; 8N, 5N, 2N, 0, 2S, 5S: 147E; 5N, 2N, 0)
Leg-3 156E_160W, 5N_3S (mainly on the Equator)
Leg-4 bringing Mirai from Honolulu to Sekinehama
6. Cruise Period :
13.Nov. 2002 〜 13.Feb. 2003. (93days)
7. Ports of Call :
Sekinehama, Japan → (Leg-1) → Guam, U.S.A → (Leg-2) → Chuuk, F.S.M. → (Leg-3) → Honolulu, U.S.A. → (Leg-4) → Sekinehama, Japan
8. Chief Scientist on Board :
Leg-1 Kunio YONEYAMA
Leg-2 Yoshifumi KURODA
Leg-3 Takeshi KAWANO
Leg-4 Takeshi KAWANO
Mission-A Kunio YONEYAMA
TEL:+81-468-67-5516 FAX:+81-468-65-3202
E-mail:yoneyamak@jamstec.go.jp
Mission-B Yoshifumi KURODA
TEL: +81-468-67-3472 FAX:+81-468-65-3202
E-mail:kuroday@jamstec.go.jp
Mission-C Takeshi KAWANO
TEL: +81-468-67-3427 FAX:+81-468-65-3202
E-mail: kawanot@jamstec.go.jp
Ocean Observation and Research Department
Japan Marine Science and Technology Center (JAMSTEC)
2-15 Natsushima, Yokosuka, 237-0061, JAPAN
