Urgent Radioactivity Sonde Observation Associated with
the 1st Fukushima Nuclear Power Generation Accident.

Geophysical Institute, Faculty of Symbiotic Systems Science
Cluster of Science and Technology
National University Corporation
Fukushima University
from Mar. 2011
Other Real Time Observation Data
@Fukushima University X-band Doppler Radar Data
@Fukushima University L-band Doppler Radar Data

Observation point
Above the Sea Level:187.0m
Latitude: N37°41′2.9″
Longitude: E140°27′18.6″
Observation organization
National University Corporation
Fukushima University
Support enterprise
This observation is supported as the society contribution business from Vaisala Co., Ltd., Sanko Tsusho Co., Ltd., NTT Data Co., Ltd. and TOTEX Co., Ltd.

@Vertical Distribution of Beta and Gamma ray

We have used the Vaisala Radiosonde RS92 with radioactivity sensor unit. The unit measures radioactivity with two low-temperature Geiger-Müller detectors. One detector measures γ-radiation, the other measures both γ-radiation and high-energy β-radiation (> 0.25 MeV). The output of the detectors is pulsed: their count rates are read by two separate counters at fixed times. Conversion to mR/h (estimated as Cs-137 radiation) is possible. The time of the file name is universal time coordinated.

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@Radiosonde Observation

The radiosonde contains sensors that measure upper air profiles of pressure, temperature and humidity. We uses VAISALA radiosondes RS92-SGP and VAISALA DigiCORA MW21 ground equipment. The radiosondes are launched on TOTEX TA 350 meteorological balloons filled with helium. The Vaisala RS92 radiosonde pressure sensor is a capacitive silicon micro-machined sensor with a measuring range from 1080 to 3 hPa and with a resolution of 0,4hPa. The temperature sensor is a capacitive thin wire sensor with a measuring range from +60°C to -90°C and with a resolution of 0.1°C. The humidity is measured by defrosting method with two heated sensors, which are thin film capacitors with a measuring range from 0 to 100% RH and with a resolution of 2%. The wind speed and direction are computed from the LORAN C chains signals or from Global Positioning System (GPS) signals. Precision of the wind vector measurement is for the LORAN C system less than 0.3 m/s and for the GPS is 0.15 m/s at 10s.

Vertical Profile of Temperature

Vertical Profile of Humidity

Vertical Profile of Wind speed and Wind Direction

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@Other Relation Data

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