Japanese Images Activity in 2001

In 2001, the Japanese Images community participated to the WEPAMA cruise on board R/V "Marion Dufresne" from Australia to Japan. More than 60 scientists, including Ph.D students, are currently involved in this research. The main areas of interest were

  • the eastern Indian Ocean, off the western coast of Australia, which has been strongly subjected to fluctuations of the Indonesian throughflow between the Pacific to Indian Ocean
  • the Indo-Pacific warm pool and areas around the Japanese islands, which have been strongly affected by the Asian Monsoon.

At the moment, six main research groups within the Japanese Images community are conducting research in the following regions:

  1. the eastern Indian Ocean,
  2. the East China Sea,
  3. the Japan Sea,
  4. the Sea of Okhotsk,
  5. the western Pacific influenced by the Oyashio Current,
  6. the western Pacific influenced by Oyashio and Kuroshio Currents, and
  7. the western Pacific influenced by the Kuroshio Currents.

Japanese paleoceanographers have been holding a national paleoceanography meeting every January to disseminate general information about IMAGES, ODP and IODP and to present talks about new scientific results on Quaternary and Phanerozoic environmental change. In September 2001, ICP-7 was held at Sapporo. This meeting was organized mainly by scientists working at Hokkaido University. Kawahata, H. and Oba, T. attended the WEPAMA workshop held in Taiwan in February 2001 and organized by Prof. Min-Te Chen to promote and prepare the WEPAMA cruise in 2001.

During the IMAGES IV cruise by R/V "Marion Dufresne" in 1998, the Japanese Images community collected a sedimentary core MD982195 from the northern East China Sea (ECS), one of the largest marginal seas. This core was investigated to understand fluctuations in terrestrial and marine environments influenced by the East Asian Monsoon during the last 42 kyr. The total abundance of pollen and spores varies from 5.1 to 24.4 x 103 grains g-1. The pollen and spores can be grouped to represent six local zones of pollen assemblages based on their abundance and components. The modern pollen assemblage (Zone MD2195-6) is consistent with the present vegetation found in Kyushu, Japan. Cooler condition with high rainfall can be estimated in Zone MD2195-1 (42-40.5 ka). Larger areas of the continental shelf in the ECS and Yellow Sea were exposed during the large drop in sea level in Zones MD2195-2 (40.5-17 ka) and -3 (17-14 ka). High abundance of non-arboreal pollen in Zones MD2195-2 and -3 is attributed to reduced distance, exposed continental shelf and ocean current system. Rainfall could have been diminished in Zone MD2195-2. Climate probably began to warm up in Zone MD2195-3. A sharp decrease in the abundance of non-arboreal pollen due to rapid transgression characterizes Zone MD2195-4 (14-8 ka). Warm temperate - subtropical evergreen broad-leaved pollens developed in Zone MD2195-5. The occurrence of Phyllocladus, originating from high land of New Guinea, Indonesia Maritime Continent and Philippines, between upper Zone MD2195-2c and Zone MD2195-4 suggests that the Kuroshio Current flowed through the ECS during the last glacial times.

Hodaka Kawahata
National Institute of Advanced Industrial Science and Technology (AIST)
Tsukuba-higashi 1-1-1,
Ibaraki 305-8567
Japan
TEL/FAX +81-298-61-3765
E-mail: h.kawahata@aist.go.jp
http://www.gsj.go.jp/~kawahata/kaw_home.html

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