A compartmental model for post-Chernobyl resuspension

A simple compartmental model is proposed to describe the transfer of Cs-137 between the lower (boundary) layer of the atmosphere and the ground for short and long term. The experimental basis for the evaluation of the model parameters (the exchange rates between the compartments), consists of the monthly deposition data sequences between 1986 - 1992 for 16 sampling stations on Romanian territory, as well as the data regarding the immediate impact (May 1986) of the Chernobyl accident on the atmosphere in Romania As a result of fitting the experimental data, the model parameters have been estimated and an analytical expression has been found for Cs-137 concentration in air as a function of these parameters and time. The site dependence of each parameter (exchange rate) has been studied. As a conclusion a new analytic expression for the resuspension factor is proposed, containing its dependence on initial conditions and the exchange rates between the model compartments. The theoretical predictions regarding the resuspension factor are in good agreement with the experimental results obtained using air concentration data from the respective sites. (orig.)