Form 3

Annual Report
LaMer, Ehime University
Date (09, 03, 2018)
To Director of LaMer
Principle Investigator: Zhang, Jing
Affiliation : Graduate School of Science andEngineering for Research,
University of Toyama
Position
Name in print

Professor
Zhang, Jing

Include the report on the result of the project/meeting in a separate sheet.
1. Project / Meeting title
化学トレーサーによる東シナ海の水塊形成と外洋への物質輸送に関する研究
Water mass formation in East China Sea and material transport to open ocean usingchemical tracers
2. Members of project / meeting
NameAffiliation

PositionContribution partPIZhang, Jing

Pro.

Supervision and managementMembersZhao, Zunhao
Katazakai, Saki
Noguchi, Tadateru
Kambayashi, Shota

M2M2
B4
D3

Measurement and Data analysis
Measurement
Measurement
Measurement and Data analysis

Guo, Xinyu

Pro.

Modeling

LaMer

Facultymember in charge【Introduction】
The 1.25 million km2 East China Sea is one of the largest marginal sea face the Pacific
Ocean. 70% of this area is shallower than 200m, which is the largest continental shelf area
in Pacific. East China Sea has the complex water circulation, the Kuroshio Current flows
from tropical northern Pacific Ocean to the East China Sea, then mixing in southern EastChina Sea and flow to the Northwest Pacific Ocean via the Tokara Strait etc.. The Kuroshio
Current branches (Taiwan Current and Tsushima Warm Current) flow northward and mixed
with the coastal water (Yellow Sea Cold Water and Changjiang Diluted Water) in thecontinental shelf, then transport to the Sea of Japan.
As a carrier of energy and material, seawater of these strait through flows play an importantrole in East China Sea and surrounding region. This study focus on the seasonal watermass structure in Tsushima Strait, establish a synergy view of chemical and physicaloceanography to clarify the 3D snapshot of the water mass structure in strait through flow
region. Then provide the detailed fraction of different water mass for further application, likethe estimation of material transportation.
【Material and Method】
Samples and datasets used in this study werecollectedineightcruises.

Thesalinity,temperature, DO and fluorescence data werecollected by CTD, the DO samples weremeasured on-board by automatic titration. δ18Oand REEs samples were stored for ourlaboratory analysis. Nutrients samples werefrozen on board and measured by automatic

Fig.1 Research region and sampling station.

analyzer.
【Result and Discussion】
Follow the T-S diagram of Tsushima Strait, probable water origins of this area are
Changjiang Diluted Water, Taiwan Warm Current, Kuroshio and Yellow Sea Cold Water. The
result of multiple tracer analysis suggested the major constitute of the water mass passthrough the Tsushima Strait origin from Kuroshio Current system. Yellow Sea Cold Water
influence this area in spring, the Changjiang Diluted Water dominate shallow layer (<50m) insummer time. Kuroshio Intermediate Water and Tsushima Warm Current exist in all seasons.
Kuroshio Intermediate Water shared 20~40% in all layers over the year, and the Tsushima
Warm Current show more variety with season change. And the flow through the west
channel and east channel of Tsushima Strait was influenced by different water mass indifferent season and show collaboration with the monsoon, especially the Changjiang
Diluted Water and Tsushima Warm Current in spring and summer. As an application of thisstudy, the distribution results can be used for the estimation of nutrients transportation. Theestimation results suggest the P-limitation of the primary production in East China Sea, andthe main origin of nutrients transporting through Tsushima Strait is Kuroshio Intermediate
Water.
【conference presentation】
1.

Zhao, Z., Zhang, J., Liu, Q., Yoshida, T., Water mass analysis of Tsushima Strait bymultiple tracers and seasonal contribution of various origin, JpGU 2017, May, Chiba,Japan.

2.

Zhang, J., Material transport and interaction between the East China Sea and thenorthwestern Pacific: joint regional GEOTRACES study in East Asia, 2017 JointIAPSO-IAMAS-IAGA Assembly, Aug., Cape Town, South Africa.

3.

Zhao, Z. and Zhang, J.，Water mass analysis of the strait-through flow in eastern EastChina Sea: approaching by multiple tracer, 2017 Annual Meeting of Annual Meeting of
the Geochemical Society of Japan, Sep., Yokohama, Japan.

4.

Zhang, J., GEOTRACES and biogeochemical studies in the Western Pacific and its
marginal seas，WESTPAC Workshop on “A framework for cooperative studies in theWestern Pacific Marginal Seas: Energy and materials exchange between land andopen ocean”. Oct. Fukuoka, Japan5.

Zhang, J. and Zhao, Z.，Water mass analysis of the strait-through flow in eastern East
China Sea: approaching by multiple tracer, Jan., Fukuoka, Japan.

6.

Tsutsumi, E., Matsuno, T., Lien, R-C., Nakamura, H., Senjyu, T., Guo, X., Zhang, J.,
Turbulent mixing within the Kuroshio in the Tokara Strait, 2018 Ocean Science Meeting.

7.

Zhang, J., Material transport in the marginal seas using chemical tracers, Marine
Geochemical Forum, Mar., Sapporo, Japan.

8.

Z. Zhao, J. Zhang, T. Matsuno, Diapycnal and isopycnal mixing? - Approach using rareearth elements-, OMIX annual meeting, Mar. 2018, Chiba, Japan