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| Titel |
Effect of the ionizing radiation on the rain-time atmospheric electric field |
| VerfasserIn |
Masatoshi Yamauchi, Masahiko Takeda, Masahiko Makino, Takeshi Owada |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074413
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| Zusammenfassung |
| The atmospheric electric field, or potential gradient (PG) at Kakioka, 150 southwest of the
Fukushima Nuclear Power Plant (NPP) shows peculiar behaviors after the accident,
March 2012 due to the conductivity enhancement in the air by the ionizing radiation.
This means that the PG provides significant information on the dynamics of the
radioactive materials. During last EGU assembly 2012, we showed that the fine-weather
PG decreased by one-two orders of magnitudes at the arrival of the radioactive
plume, and that the PG recovered in various way depending on various types of
re-suspension processes in addition to the physical decay of the deposited radioactive
materials.
We extended this work to the rain-time PG, which is very simple because of high
variability of the PG depending on the cloud types and distribution. We yet found a statistical
difference between rain-time PGs before and after the Fukushima NPP Accident: one-hour
averaged rain-time PG during the first 45 days after the accident is not as much scattered to
the negative side as those during the same period of different years or during 40 days before
accident. Further examination of one-minute averaged data (1 Hz sampling) during the
second half March for 2006-2012 revealed that this difference comes from short time-spans
of negative peaks rather than the peak value after the accident compared to those before the
accident. On the other hand, characteristics of positive peaks (cloud without rain) are
unchanged.
The results suggest either (1) the effect on the local charges in the rain cloud is
narrowed under high dose of ionized radiation, making positive charges in the cloud
less shielded by the negative charges, or (2) negative charge of ionized aerosol
decays much faster under higher dose of ionized radiation due to the shortened
time constant of the ionized aerosol (- 1-Ïă, where Ïă is the atmospheric electric
conductivity). |
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