Real-time tracer dispersion simulations in Oklahoma City using the locally mesh-refined lattice Boltzmann method

Onodera, Naoyuki   ; Idomura, Yasuhiro   ; Hasegawa, Yuta   ; Nakayama, Hiromasa   ; Shimokawabe, Takashi*; Aoki, Takayuki*

A plume dispersion simulation code named CityLBM enables a real time simulation for several km by applying adaptive mesh refinement (AMR) method on GPU supercomputers. We assess plume dispersion problems in the complex urban environment of Oklahoma City (JU2003). Realistic mesoscale wind boundary conditions of JU2003 produced by a Weather Research and Forecasting Model (WRF), building structures, and a plant canopy model are introduced to CityLBM. Ensemble calculations are performed to reduce turbulence uncertainties. The statistics of the plume dispersion field, mean and max concentrations show that ensemble calculations improve the accuracy of the estimation, and the ensemble-averaged concentration values in the simulations over 4 km areas with 2-m resolution satisfied factor 2 agreements for 70% of 24 target measurement points and periods in JU2003.