3.2 On-Line TCM for Fukushima




A new procedurethis link opens in a new window has been developed and tested to provide operational plume forecasts in real-time by continuously updating previous day's emissions as new meteorological data become available. Simulations are divided into smaller time segments and each segment is continued as an independent calculation using a unit source emission. The unit source calculations give the dispersion factors from the release point for every emission period to each downwind grid location, defining how much of the emissions are transferred to each location varying as a function of time, which is defined as the Transfer Coefficient Matrix (TCM). The TCM is computed for inert and depositing species and when quantitative air concentration results are required, the final air concentration is computed in a simple post-processing step by multiplying the TCM by the appropriate emission rate and radioactive decay constant. Results for multiple emission scenarios can easily be created and used to optimize model results as more measurement data become available.