Fukushima - Where is the radioactive water_ «GEOMAR - HelmFholtz Centre for Ocean Research Kiel

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  • 5/30/13 Fukushima - Where is the radioactive water? GEOMAR - Helmholtz Centre for Ocean Research Kiel

    www.geomar.de/news/article/fukushima-wo-bleibt-das-radioaktive-wasser/ 1/2

    Simulated expansion of the contaminated Wassesthe summer of 2012, 16 months after the nucleardisaster. The colors illustrate the dilution relativeto the original starting concentration in theJapanese coastal w aters: the highest values (red) are about one-thousandth of the values inApril 2011.

    06.07.2012

    Fukushima - Where is the radioactive water?

    Provide strong eddy mixing in the Pacific

    09.07.2012/Kiel. The nuclear disaster in Fukushima, Japan already getsforgotten again. But large amounts of the released radioactive substancesspread remains from the Pacific. Scientists at the GEOMAR | HelmholtzCentre for Ocean Research Kiel have analyzed the long-term spread withthe help of a model study. After the strong mixing by oceanic eddy providesfor a rapid dilution of the radioactive water. When the foothills reach theNorth American coast in about three years, the radioactivity shouldtherefore already be below the values that are still to be found as a resultof the Chernobyl disaster in the Baltic Sea.

    A major part of it came through the atmosphere, but also

    partly by direct introduction into the Pacific Ocean, including long-lived isotopes,

    such as the highly soluble in seawater cesium 137th Using detailed computer

    simulations, researchers have GEOMAR | Helmholtz Centre for Ocean Research

    Kiel examined the long-term propagation. "In our models, we have placed great

    emphasis on a realistic representation of finer details of the flows," said the team

    leader, Prof. Claus Bning, "because the fabric spread not only through the main

    flow, the Kuroshio, but mainly by intense and highly variable eddy dominated. "

    "According to our model calculations should have been already distributed over

    almost half the North Pacific be through these strong turbulence, the radioactive

    water," said graduate oceanographer Erik Behrens, lead author of the published in

    the international journal "Environmental Research Letters" study. "In addition,

    winter storms have mixed the water to depths of around 500 meters." The

    associated dilution makes the modeling of a rapid decrease in cesium

    concentrations.

    The effect of the wide ocean mixing is particularly evident when one compares the

    simulated model in the time course of radiation levels in the Pacific with the

    conditions in the Baltic Sea. "The flowed into the Pacific in March and April 2011

    amount of radioactivity was at least three times as large as the one that was

    registered in 1986 as a result of the Chernobyl disaster in the Baltic," says Bning.

    "Nevertheless, we simulated radiation levels in the Pacific are already lower than

    the values that can be found today, 26 years after Chernobyl, in the Baltic Sea."

    After the simulation model first foothills of the contaminated water should roam the

    Hawaiian Islands in the fall of 2013 and approximately two to three years later

    reached the North American coast. Unlike at the sea surface floating debris, which

    are distributed by the wind, the radioactive water is transported solely by the

    currents below the sea surface. The other concomitant dilution will significantly

    slow down but now, since the oceanic eddy in the eastern Pacific are much weaker

    than in the Kuroshio region. Therefore, the radiation levels in the North Pacific are

    significantly higher than those before the disaster for years to come.

    We would be very interested Claus Bning his team to a direct comparison

    measurements. "Then we could immediately see if we are right even when the

    absolute values of the concentrations," says Prof. Bning. Such data are for the

    Kiel scientists but are not currently available.

    Original work:

    Behrens, E., FU Schwarzkopf, JF Luebbecke and CW Bning, 2012: Model

    simulations on the long-term dispersal of 137 . Cs released into the Pacific Ocean

    off Fukushima Environmental Research Letters , 7 , http://dx.doi

    .org/10.1088/1748-9326/7/3/034004

    By the Fukushima nuclear disaster in March last year, large amounts of radioactive

    materials were released. Original text

    Durch die Reaktorkatastrophe von Fukushima im Mrz letzten Jahreswurden groe Mengen radioaktiven Materials freigesetzt.

    Contribute a better translation

  • 5/30/13 Fukushima - Where is the radioactive water? GEOMAR - Helmholtz Centre for Ocean Research Kiel

    www.geomar.de/news/article/fukushima-wo-bleibt-das-radioaktive-wasser/ 2/2

    High Resolution Image:

    Simulated expansion of the contaminated Wasses the summer of 2012 , 16

    months after the nuclear disaster. The colors illustrate the dilution relative to the

    original starting concentration in the Japanese coastal waters: the highest values

    (red) are about one-thousandth of the values in April 2011. Source: GEOMAR.

    Animation of the spread of contaminated water . Video sequence of the time course

    over a period of 10 years after the nuclear disaster. The colors illustrate the dilution

    relative to the original concentration in the Japanese coastal waters. Source:

    GEOMAR.

    Contact:

    Prof. Dr. Claus Bning (theory and modeling, GEOMAR), tel 600-4003 0431,

    cboening@geomar.de

    January Steffen (GEOMAR, Communications & Media) Tel: 600-2811 0431,

    jsteffen@geomar.de

    This press release as pdf .

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