Mean residence time of the shelf water in the East China and the Yellow Seas determined by sup 228 Ra/ sup 226 Ra measurements

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/GL016i011p01297· OSTI ID:5511642

Nozaki, Yoshiyuki ^[1]; Kasemsupaya, Vimonrut; Tsubota, Hiroyuki ^[2]

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1. Univ. of Tokyo (Japan)
2. Hiroshima Univ. (Japan)

Increasing attention of oceanographers has recently been paid on East Asian marginal seas regarding their role on the global environment, yet geochemical investigations have been few to date. The authors here report new data on the distribution of {sup 228}Ra and {sup 226}Ra in the surface water of the East China and the Yellow seas in an effort to constrain the time necessary for the coastal and shelf waters to exchange with offshore waters. Such information is needed in evaluating the exchange of heat and water across the air-sea interface that affects the local climate and the fate of pollutants, nutrients and weathering products supplied from the continent. Based on the Ra isotope signals, the authors have estimated that the shelf water component contributes {approximately} 20% of the Tsushima Current water passing through the Tsushima Strait and the mean residence time for the shelf water to mix with the Kuroshio surface water is {approximately}2.3 years. As many of materials derived from the continent such as heavy metals and the nutrients have their mean residence times less than a few months in the nearshore and shelf waters, they must largely deposit on the shelf sediments prior to the transport from the shelf to the open sea by mixing.

• OSTI ID: 5511642
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 16:11; ISSN GPRLA; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540311* -- Environment
Aquatic-- Basic Studies-- Radiometric Techniques-- (1990-)
AIR
ALKALINE EARTH ISOTOPES
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14 DECAY RADIOISOTOPES
CHINA SEA
CLIMATES
CONTINENTAL MARGIN
CONTINENTAL SHELF
CURRENTS
DEPOSITION
DISTRIBUTION
ENVIRONMENTAL TRANSPORT
EVEN-EVEN NUCLEI
FLUIDS
GASES
HEAVY ION DECAY RADIOISOTOPES
HEAVY NUCLEI
INTERFACES
INTERNAL CONVERSION RADIOISOTOPES
ISOTOPE RATIO
ISOTOPES
MASS TRANSFER
MIXING
NUCLEI
OCEANIC CIRCULATION
OCEANOGRAPHY
OFFSHORE SITES
PACIFIC OCEAN
POLLUTANTS
POLLUTION
RADIOISOTOPES
RADIUM 226
RADIUM 228
RADIUM ISOTOPES
SEAS
SURFACE WATERS
TIME DEPENDENCE
WATER CURRENTS
WATER POLLUTION
YEARS LIVING RADIOISOTOPES