Refine your search:     
Report No.
 - 
Search Results: Records 1-13 displayed on this page of 13
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

JAEA Reports

Establishment of database for Japan Sea parameters on marine environment and radioactivity (JASPER), 2; Radiocarbon and oceanographic properties

Otosaka, Shigeyoshi; Suzuki, Takashi; Tanaka, Takayuki; Ito, Toshimichi; Kobayashi, Takuya; Kawamura, Hideyuki; Minakawa, Masayuki*; Aramaki, Takafumi*; Senju, Tomoharu*; Togawa, Orihiko

JAEA-Data/Code 2009-020, 27 Pages, 2010/02

JAEA-Data-Code-2009-020.pdf:2.45MB

The database for the Japan Sea parameters on marine environment and radionuclides (JASPER) has been established by the Japan Atomic Energy Agency as a product of the Japan Sea Expeditions. By the previous version of the database, data for representative anthropogenic radionuclides were opened to public. And now, data for radiocarbon and fundamental oceanographic properties (salinity, temperature, dissolved oxygen) including nutrients (silicate, phosphate, nitrate and nitrite) are released as the second volume of the database. In the second volume, 20,398 data records are stored including 2,695 data for temperature, 2,883 data for salinity, 2,109 data for dissolved oxygen, 11,051 data for the nutrients, and 1,660 data for radiocarbon. The database will be a strong tool for the continuous monitoring for contamination by anthropogenic radionuclides, studies on biogeochemical cycle, and development and validation of models for numerical simulations in the sea.

Journal Articles

Distribution of radiocarbon and bottom water circulation in the Japan Sea

Aramaki, Takafumi*; Togawa, Orihiko; Otosaka, Shigeyoshi; Suzuki, Takashi; Amano, Hikaru; Tanaka, Takayuki; Senju, Tomoharu*; Minakawa, Masayuki*

JAEA-Conf 2008-005, p.149 - 152, 2008/03

no abstracts in English

Journal Articles

Iron in the Japan Sea and its implications for the physical processes in deep water

Takata, Hyoe*; Kuma, Kenshi*; Isoda, Yutaka*; Otosaka, Shigeyoshi; Senju, Tomoharu*; Minakawa, Masayuki*

Geophysical Research Letters, 35(2), p.L02606_1 - L02606_5, 2008/01

Concentrations of iron in seawater (dissolved and labile dissolved phases) in the two basins (Yamato Basin and Japan Basin) of the Japan Sea are measured and the origin and behavior of iron were discussed. Extremely high vertically integrated total dissolvable Fe inventories (300-350 $$mu$$mol m$$^{-2}$$) were observed at the surface water in both basins (0-200 m depth), and was probably resulting from high atmospheric Fe input to the surface water. Labile dissolved Fe in both basins was characterized by mid-depth (1-2 km depth) maxima, which were regulated by the competition between dissolved Fe input from the microbial decomposition of sinking biogenic organic matter and Fe removal by particulate scavenging. The distributions of Fe in the Japan Sea would play an important role in understanding the biogeochemical cycle of iron in the ocean.

Journal Articles

Circulation in the northern Japan Sea studied chiefly with radiocarbon

Aramaki, Takafumi*; Senju, Tomoharu*; Togawa, Orihiko; Otosaka, Shigeyoshi; Suzuki, Takashi; Kitamura, Toshikatsu; Amano, Hikaru; Volkov, Y. N.*

Radiocarbon, 49(2), p.915 - 924, 2007/10

 Times Cited Count:8 Percentile:26.24(Geochemistry & Geophysics)

no abstracts in English

Journal Articles

Benthic front and the Yamato Basin Bottom Water in the Japan Sea

Senju, Tomoharu*; Isoda, Yutaka*; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Fujio, Shinzo*; Yanagimoto, Daigo*; Suzuki, Takashi; Kuma, Kenshi*; Mori, Kosuke*

Journal of Oceanography, 61(6), p.1047 - 1058, 2005/12

 Times Cited Count:7 Percentile:16.33(Oceanography)

The detail structure of the Bottom Water in the Japan Sea was revealed by the hydrographic observations. The Yamato Basin Bottom Water (YBBW) exhibits higher temperature, lower dissolved oxygen, and higher nutrients concentrations than those in the Japan Basin Bottom Water (JBBW). Both Bottom Waters meet around the boundary region between the Yamato and the Japan Basins, and form a clear benthic front. It is inferred from the property distributions that the JBBW flowing into the Yamato Basin is trapped by the cyclonic circulation in the basin, and modified to the YBBW in the course of the circulation through the vertical diffusion, geothermal heating and oxygen consumption. The thermal balance of in the YYBW was examined using a box-model. The results show that the effect of geothermal heating has about 70 per-cent of magnitude to the vertical thermal diffusion and both terms cancel the advection term of the cold JBBW from the Japan Basin. The box-model also estimated the averaged residence time for the YBBW was 9.1 years.

Journal Articles

Anthropogenic radionuclides in seawater of the Japan Sea; The Results of recent observations and the temporal change of concentrations

Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Kawamura, Hideyuki; Amano, Hikaru; Senju, Tomoharu*; Chaykovskaya, E. L.*; et al.

Journal of Nuclear Science and Technology, 42(1), p.90 - 100, 2005/01

 Times Cited Count:13 Percentile:68.06(Nuclear Science & Technology)

During 1996-2002, a wide-area research project on anthropogenic radionuclides was done in the Japanese and Russian EEZ of the Japan Sea to investigate their migration. As the results of expeditions in 2001 and 2002, (1) the concentrations and distributions of radionuclides are similar to the results of previous, (2) inventories of these radionuclides indicate accumulation in the Japan Sea seawater compared to the amounts supplied by global fallout, (3) $$^{90}$$Sr and $$^{137}$$Cs concentrations in intermediate layer show temporal variations, and 4) the variations may reflect the water mass movement in upper part of the Japan Sea.

Journal Articles

Benthic front between the Japan Basin and the Yamato Basin in the Japan Sea

Senju, Tomoharu*; Isoda, Yutaka*; Aramaki, Takafumi; Otosaka, Shigeyoshi; Suzuki, Takashi; Kuma, Kenshi*; Mori, Kosuke*

Proceedings of 12th PAMS/JECSS Workshop, p.3_4_1 - 3_4_4, 2003/11

Abyssal water mass distribution from the Yamato Basin to the Japan Basin in the Japan Sea was observed on the R/V Hakuho-Maru cruise, KH02-3 (October 14-19, 2002). The bottom layer in the Yamato Basin was occupied by the water of higher temperature and lower oxygen compared to that in the Japan Basin. As a result, a benthic front of potential temperature and dissolved oxygen was formed between the Yamato and Japan Basins. Dissolved oxygen and nutrients concentrations show that the bottom water in the Yamato Basin is older than that in the Japan Basin. This indicates the existence of the Yamato Basin Water, which is modified bottom water by the closed circulation in the Yamato Basin. The structure of the benthic front suggests an estuary-like circulation around the mouth of the Yamato Basin; outflow from the Yamato Basin lying on the inflow from the Japan Basin. The highest oxygen water was found on the slope of southern periphery of the Japan Basin. This is considered to be the bottom water from the west transported by the cyclonic circulation in the Japan Basin.

Journal Articles

Anthropogenic radionuclides in seawater of the Japan Sea; The Results of recent expeditions carried out in the Japanese and Russian EEZ

Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Senju, Tomoharu*; Chaykovskaya, E. L.*; Lishavskaya, T. S.*; Karasev, E. V.*; et al.

Proceedings of International Symposium on Radioecology and Environmental Dosimetry, p.396 - 401, 2003/10

no abstracts in English

Journal Articles

Anthropogenic radionuclides in the Japan Sea; Their distributions and transport processes

Ito, Toshimichi; Aramaki, Takafumi; Kitamura, Toshikatsu; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Senju, Tomoharu*; Chaykovskaya, E. L.*; Karasev, E. V.*; et al.

Journal of Environmental Radioactivity, 68(3), p.249 - 267, 2003/07

 Times Cited Count:35 Percentile:61.29(Environmental Sciences)

The anthropogenic radionuclides, $$^{90}$$Sr, $$^{137}$$Cs and $$^{239+240}$$Pu, in the seawater column of the Japan Sea were measured during 1997-2000. The vertical profiles of radionuclide concentrations showed their typical features; exponential decrease with depth for the $$^{90}$$Sr and $$^{137}$$Cs and surface minimum - subsurface maximum for the $$^{239+240}$$Pu, and there are no substantial differences between the present study and the previous ones. The area-averaged concentrations and the inventories of radionuclides in the Japan Sea are higher than those in the Northwest Pacific Ocean. In the spatial distributions, high inventory area extends and intrudes from the Japan Basin into the Yamato Basin. It is suggested that radionuclides sink by the vertical transport occurring mainly in the Japan Basin then advect into the Yamato Basin after detouring around the Yamato Rise, and finally, they are accumulated in the deep seawater of the Japan Sea.

Journal Articles

Renewal of the bottom water after the winter 2000-2001 may spin-up the thermohaline circulation in the Japan Sea

Senju, Tomoharu*; Aramaki, Takafumi; Otosaka, Shigeyoshi; Togawa, Orihiko; Danchenkov, M. A.*; Karasev, E.*; Volkov, Y. N.*

Geophysical Research Letters, 29(7), p.53_1 - 53_4, 2002/04

The newly formed bottom water in the Japan Sea was observed in the summer of 2001 after the severe winter 2000-2001. The new bottom water, which was observed in the northwestern Japan Sea, showed low temperature, high salinity, high dissolved oxygen and low nutrients concentration compared to the old bottom water. The distribution of the bottom water indicates that the deep convection occurred in the area of south off Vladivostok, not the northern Japan Sea, and then the bottom water was advected to the observation area from the convection region. The record of current meters suggests that the deep convection occurred in the early-February, because strong flows faster than 10 cms-1 appeared abruptly from mid-February 2001. This formation event may contribute not only the relaxation of the anoxic trend in the bottom layer but also the spin-up of the thermohaline circulation in the Japan Sea.

Oral presentation

Distribution of radiocarbon and the bottom water circulation in the Japan Sea

Aramaki, Takafumi*; Togawa, Orihiko; Otosaka, Shigeyoshi; Suzuki, Takashi; Senju, Tomoharu*; Minakawa, Masayuki*

no journal, , 

no abstracts in English

Oral presentation

Vertical profile of DOC-14 in the Japan Sea

Tanaka, Takayuki; Otosaka, Shigeyoshi; Amano, Hikaru; Togawa, Orihiko; Senju, Tomoharu*; Isoda, Yutaka*; Kuma, Kenshi*

no journal, , 

no abstracts in English

Oral presentation

Circulation and properties of deepwater in the Japan Sea inferred from distribution of multiple tracers

Aramaki, Takafumi*; Otosaka, Shigeyoshi; Takahata, Naoto*; Isoda, Yutaka*; Kuma, Kenshi*; Senju, Tomoharu*

no journal, , 

Deep part of the Japan Sea ($$>$$ 2000m depth) consists of seawater with uniform salinity and temperature. This structure complicated us to understand the transport processes of the deepwater circulation in the sea. By the Japan Sea Expeditions carried out by JAEA from 1997 to 2002, the authors measured isotopic ratio of radiocarbon in seawater as a tracer of seawater movement. As a result, it has been inferred that the deep water is formed in the plural regions of the sea and that the northwestern region is primary region of deep water formation. In the present study, we obtained data of tritium concentration and isotopic ratio of helium as additional indicators, and discussed the detailed deepwater circulation to describe another origin of the deep water.

13 (Records 1-13 displayed on this page)
  • 1