The Lagrangian Operational Dispersion Integrator, LODI, is an atmospheric dispersion model developed for

operational emergency response within the U.S. Department of Energy’s National Atmospheric Release

Advisory Center (NARAC). It solves the 3-D advection diffusion equation using a Lagrangian stochastic,

Monte Carlo method which calculates possible trajectories of fluid “particles” in a turbulent flow. Particles are marked at the source of a contaminant with an appropriate amount of contaminant mass based upon prescribed mass emission rates. These computational particles can also be given total density and diameters, sampled from an input aerosol size distribution, which are used to calculate gravitational settling and deposition. Initial particle

positions are assigned by sampling the spatial distribution based on the geometry of the source. A large number

of independent particle trajectories are calculated by moving particles in response to the various processes, such as mean wind advection, gravitational settling and turbulent dispersion, represented within the simulation. The mean contaminant air concentration is estimated from the spatial distribution of the particles at a particular time.

Date Of Record Release | 2009-06-15 14:51:01 |
---|---|

Description | The Lagrangian Operational Dispersion Integrator, LODI, is an atmospheric dispersion model developed for operational emergency response within the U.S. Department of Energy’s National Atmospheric Release Advisory Center (NARAC). It solves the 3-D advection diffusion equation using a Lagrangian stochastic, Monte Carlo method which calculates possible trajectories of fluid “particles” in a turbulent flow. Particles are marked at the source of a contaminant with an appropriate amount of contaminant mass based upon prescribed mass emission rates. These computational particles can also be given total density and diameters, sampled from an input aerosol size distribution, which are used to calculate gravitational settling and deposition. Initial particle positions are assigned by sampling the spatial distribution based on the geometry of the source. A large number of independent particle trajectories are calculated by moving particles in response to the various processes, such as mean wind advection, gravitational settling and turbulent dispersion, represented within the simulation. The mean contaminant air concentration is estimated from the spatial distribution of the particles at a particular time. |

Classification | |

Resource Type | |

Format | |

Subject | |

Source | National Atmospheric Release Advisory Center |

Keyword | Atmospheric dispersion model, Emergency response, 3-D, Advection diffusion equation |

Selector | Stith |

Date Of Record Creation | 2009-06-15 14:35:18 |

Education Level | |

Date Last Modified | 2009-06-15 14:51:01 |

Creator | John M. Leone, Jr., John S. Nasstrom, Denise M. Maddix, David J. Larson Gayle Sugiyama, Donald L. |

Language | English |

Contact ATEEC 563.441.4087 or by email ateec@eicc.edu