Analysis and calibration of Safecasta data relative to the 2011 Fukushima Daiichi nuclear accident
Abstract
Citizen-led movements producing scientific hazard data during disasters are increasingly common. After the Japanese earthquake-triggered tsunami in 2011, and the resulting radioactive releases at the damaged Fukushima Daiichi nuclear power plants, citizens monitored on-ground levels of radiation with innovative mobile devices built from off-the-shelf components. To date, the citizen-led Safecast project has recorded 50 million radiation measurements world- wide, with the majority of these measurements from Japan. A robust methodology is presented to calibrate contributed Safecast radiation measurements acquired between 2011 and 2016 in the Fukushima prefecture of Japan. The Safecast data are calibrated using official observations acquired by the U.S. Department of Energy at the time of the 2011 Fukushima Daiichi power plant nuclear accident. The methodology performs a series of interpolations between the official and contributed datasets at specific time windows and at corresponding spatial locations. The coefficients found are aggregated and interpolated using cubic and linear methods to generate time dependent calibration function. Normal background radiation, decay rates and missing values are taken into account during the analysis. Results show that the official Safecast static transformation function overestimates the official measurements because it fails to capture the presence of two different Cesium isotopes and their changing ratio with time. The new time dependent calibration function takes into account the presence of different Cesium isotopes, and minimizes the error between official and contributed data. This time dependent Safecast calibration function is necessary until 2030, after which date the error caused by the isotopes ratio will become negligible.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMNH33C..03C
- Keywords:
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- 1916 Data and information discovery;
- INFORMATICS;
- 1976 Software tools and services;
- INFORMATICS;
- 4332 Disaster resilience;
- NATURAL HAZARDS;
- 4333 Disaster risk analysis and assessment;
- NATURAL HAZARDS