jump to content

Home > Description of observational data > Notice about the data

Notice about the data

  • This site shows a real-time data. If the wrong data is provided because of machine trouble or communication failure, it will be corrected later.
  • A measuring device and computer systems are checked at regular intervals. During the routine maintenance check, the data will be shown as "Under maintenance", "(blank)" or "-".
  • For information of the maintenance check, please refer to the Top Page of this site.





 As to the monitoring station operated by Fukui Prefecture, the maximum value of wind velocity is set to 20m/s. If the wind velocity exceeds this level, this date is shown as "In Preparation". When the wind velocity is under the minimum measurable value (0.0- 2.0m/s), window direction is shown as “calm”.

Notice about the shown data

・The radiation dose rate measuring device and the data unit
 The radiation dose rate is investigated by checking the air radiation dose (Gamma( )-ray dose) around the spot using the low dose detector (NaI scintillation detector) .
 The unit of the radiation dose rate is shown as μGy/h (microgray per hour), which is the air absorbed dose per hour. Gy (gray) is the unit that shows quantity of the energy that the object absorbed from the air radiation dose, and “μ” is the symbol that expressed one millionth.
 The dose rate shown on this site has been converted to the dose equivalent rate to express the influence on human health. The conversion is based on Environmental Radiation Monitoring Guidance (Old Nuclear Safety Commission) and defined as 1μGy/h (microgray per hour) = 1 1μSv/h (microsievert per hour).

・The Precaution Level of the Radiation Dose Rate
 Fukui Prefectural Environmental Radiation Research and Monitoring Center defined the precaution level of the radiation dose rate as 250nGy/h, and when the detected value exceeds this threshold, investigation to identify the cause is to be done regardless of the night on a holiday. Also, the information about it is to be shown on the top page of this site.
 The value 250nGy/h is determined from the result of the observation so far in Fukui Prefecture as  no higher value is supposed to be detected from the natural factors, such as rain or snowfall. Additionally, other than rain or snowfall, it is known that thunderbolt may cause to raise the radiation dose rate momentarily.

Top of Page

Top of Page