Spatial variation of radiocaesium deposition in Cumbria

Over the past five decades Cumbria has been subject to radiocaesium deposition from a number of sources. In the event of a future nuclear accident, estimates of baseline radiocaesium deposition in Cumbria would be indispensable. This paper describes the application of ordinary block kriging to estimate the spatial variation of total ¹³⁷Cs and ¹³⁴Cs. This study has raised a number of issues regarding the application of kriging. Transformation of input data was necessary to improve the optimality of the standard kriging estimator. Finally, observations of ¹³⁷Cs and ¹³⁴Cs from a similar range of locations exhibit different spatial characteristics. This can be explained by differences in radioactive half-lives and differences in the deposition of the two isotopes.