1 / 9

M. Yamauchi 1 , M. Takeda 2 , M. Makino 3 , and S. Nagamachi 4

Atmospheric electricity by the radioactive aerosol after the Fukushima nuclear accident: an overview. M. Yamauchi 1 , M. Takeda 2 , M. Makino 3 , and S. Nagamachi 4. (1) Swedish Institute of Space Physics (IRF), Kiruna, Sweden (2) Kyoto University, Japan

cashcraft
Download Presentation

M. Yamauchi 1 , M. Takeda 2 , M. Makino 3 , and S. Nagamachi 4

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Atmospheric electricity by the radioactive aerosol after the Fukushima nuclear accident: an overview M. Yamauchi1, M. Takeda2, M. Makino3, and S. Nagamachi4 (1) Swedish Institute of Space Physics (IRF), Kiruna, Sweden (2) Kyoto University, Japan (3) National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan (4) Kakioka Magnetic Observatory, Japan Meteorological Agency, Ishioka, Japan Poster X4.242@GI1.2 (EGU2017-5610), Thursday (2016-4-27)

  2. Detection Principle The vertical (downward) component of the DC atmospheric electric field (called potential gradient: PG) is regulated by nearly constant current (as a part of global circuit). However, only wet contamination (one-time sudden drop and slow recovery) has been reported after nuclear accident / test. Fukushima (Kakioka: 150 km away from source) showed more unique features. (1) PG recovered shortly after the initial deposition, indicating a dry deposition and blow up. (2) daily variation after the wet deposition, indicating re-suspension. (3) short time-scale for PG peaks that are relevant to cloud electricity, indicating electrostatic shielding effect by extra ions

  3. (1) PG dropped to zero without rain on 14 March and partially recovered (1/4 of normal level) on 16 March at higher dose rate. "Low-PG" must be distributed to higher altitude than previous cases  "New feature for dry deposition" (air is not cleaned) Rain cf. after Chernobyl (PG at Helsinki) Accident 29/4 1/5 10/5

  4. (2) PG showed unexpected daily variation after wed deposition 2000-2009 statistics "Low-PG" must again be distributed to higher altitude, but why this was not reported in the past?  "New feature for Japanese climate" (strong daily wind and deep light soil that is easily blow up)

  5. interpretation (a) (b) (c) (c)

  6. (3) PG during rain/cloud needs high-resolution data! Since the air is also contaminated, high conductance should affect detection of the cloud charge (e.g., shielding). From PG value, we expect increase of conductivity about x10 near ground and about x3 in the air. Example (1-h data) beforeaccident Afteraccident We expect smaller PG after the accident, but need to examine

  7. (3a) PG peak value did not change, but time-scale changed! (3b) Effect is largest under "weak" rain (strong rain cleans the air!)

  8. Summary: PG@ Kakioka tells many things • (1) 14-20 March = floating radionuclide • 14 March: Dry deposition on 14 March at Kakioka, 150 km. • 16-20 March: Strong re-suspension by wind. • (2) - 20 April = some re-suspension • 20-21 March: Wet deposition at Kakioka by the first substantial rain. • - 20 April : Re-suspension by daily wind. Transport from highly-contaminated to moderately-contaminated areas. • (3) - 20 April = shielding during weak rain • - 20 April : Air is contaminated, and strong rain cleans off.

  9. (a) Fallout Three types of fallout (b) (c) (c) (b) (a)

More Related