Cs-137 fallout inventories in Iceland - estimating deposition from precipitation data

Iceland was identified in the Arctic Monitoring and Assessment Report as one of the Arctic areas which received the most global fallout from atmospheric nuclear weapons tests, but measurements of contamination were sparse, and are difficult due to the remote and inaccessible terrain of much of the country. Measurements of global 1 3 7Cs deposition have been made at sites close to meteorological stations to ensure that precipitation data were of high quality. The measured data have been compared with different methods of predicting , 3 7Cs deposition. The AMAP modeling approach, based on fallout and precipitation data, was used based on a monitoring station near Reykjavik. The availability of good precipitation data and locally based estimates of time dependent ratios of 1 3 7Cs deposition to precipitation during the fallout period gave a better correlation between predicted and observed 1 3 7Cs deposition (1^=0.96) than that achieved using the heterogeneous set of data collected by AMAP over the whole of the Arctic. The method allows a fallout map to be produced for the whole of Iceland for any time period during or after deposition.