Turbulent analysis of strong wind variability by merging numerical weather prediction and large-Eddy simulation models

Takemi, Tetsuya*; Nakayama, Hiromasa   ; Nagai, Haruyasu  

The purpose of this study is to propose a numerical approach for quantitative analyses of wind flows in real urban areas. We conduct numerical simulations for strong winds and gusts over the central business district of Tokyo during the passage of Typhoon Melor (2009). The WRF model is used for the meteorological simulation; Mesoscale Analysis data by JMA are used as the initial and boundary conditions. The nesting technique is used to resolve the area including central Tokyo at 60-m grid. The high-resolution temporal and spatial data from the WRF model are then used as the initial and boundary conditions for an LES model. The lower boundary of the LES model is determined by a building-height dataset for the analysis area. A turbulent simulation of wind flows in the realistic urban area is conducted with the LES model. The simulation successfully captures the wind variability and peaks observed at a surface site of JMA.