Lawrence Livermore National Laboratory

LLNL/NARAC continually updates key physics processes in its models. One focus of these efforts is on the development of high-resolution simulation capabilities informed by newly available data. Recent examples include:

  • New precipitation scavenging and wet deposition methods
  • Improved methods for dry deposition for both particles and gases
  • Urban canopy models
  • Updated radionuclide resuspension model (Maxwell and Anspaugh, 2011)

Precipitation is a highly effective process for removing material from an airborne plume and depositing it on the ground. The side by side figures show the difference in the relative ground deposition concentration patterns when (1) dry deposition but no wet deposition is included (left panel) and (2) both dry deposition and spatially and temporally-varying precipitation scavenging are included (right panel). The yellow X indicates the release location at the Fukushima Dai-ichi nuclear power plant.
(Sugiyama et al., 2012)

Comparison of LODI predictions of the wet deposition of 137Cs generated using wind and precipitation data from the Global Forecast System (GFS) numerical weather prediction model (left panel) and higher-resolution meteorological data developed from the Weather Research and Forecast (WRF) model (right panel). The complex wet deposition structure in the mountains to the west of the Fukushima Dai-ichi power plant produced using WRF data is not seen in the lower-resolution GFS results. (Courtesy of Matthew Simpson)