Mapping terrestrial [formula omitted]-dose rate in Europe based on routine monitoring data

Abstract

After the nuclear reactor accident in Chernobyl in 1986, most countries of the European Union (EU) established monitoring networks measuring outdoor γ -dose rates for early warning. The data are composite values γ -dose rate due to terrestrial, cosmic and artificial radiation sources, and in most cases also include some instrument background. While EURDEP is mainly designed for exchanging and stocking data during radiological emergencies, the data it is storing in its database may potentially contain valuable information about spatio-temporal variations of the Rn 222 source term which can be used for the validation of atmospheric transport models and other atmospheric tracer applications. The use of γ -dose rates as a proxy for outdoor radon concentrations is indeed possible if one can extract the terrestrial γ -dose rate contribution from the values reported in EURDEP. It is the purpose of this paper to discuss the preparation of the terrestrial γ -dose rates using EURDEP data and to present seasonal maps of terrestrial γ -dose rates in Europe. Such maps could be used for the preparation of Rn 222 source term which can be used for the validation of atmospheric transport models as well as for exploring variations in soil moisture content, an important parameter in flood prediction. These applications are the focus of the ongoing studies, but beyond the scope of this paper. In this paper, we show how the terrestrial γ -dose rate can be derived from the emergency monitoring data and two seasonal maps of γ -dose rates at the European scale are produced using geostatistics.