[A-AS01] Extreme weathers and disasters in urban environments in East Asia, related to climate change

[AAS01-P03] Development of the City-Scale Large Eddy Simulation Model (City-LES) for evaluating heat stress mitigation measures

*Hiroyuki Kusaka¹, Ryosaku Ikeda², Takuto Sato¹, Satoru Iizuka³, Taisuke Boku¹ (1.University of Tsukuba, 2.Weathernews Inc, 3.Nagoya University)

Keywords:LES model, heat stress, mitigation strategy, dry-mist spraying, street tree, WBGT

Meso-scale and micro-scale meteorological models have been largely contributing to urban climatology. This talk will introduce highlights of city-scale meteorological modeling efforts by our group, specifically the new version of our own city-scale large eddy simulation (LES) model named City-LES (Ikeda et al. 2015). The main features of this model are as follows. (1) This model numerically and three-dimensionally simulates/predicts the time-varying spatial distributions of temperature, humidity, winds, radiations, and cloud/fog. (2) The dynamics core is based on non-hydrostatic Boussinesq approximation equations and the model considers atmospheric static stability. (3) The spatial resolution of the model is in order of 1 to 10 m and the model can resolve buildings and roadside trees. (4) Long- and short-wave radiations are calculated three-dimensionally and multiple reflections of the radiations within urban canopy layers. (5) Using the model, we can evaluate the various mitigation strategies of uncomfortable thermal environments, for instance, installation of dry-mist spraying, roadside trees, cool pavements, and green/cool roofs. (6) The model outputs various heat stress indices (UTCI, WBGT, THI, PMV, MRT). (7) The model simulations are performed with the dynamical downscaling from mesoscale meteorological models such as the WRF model. The talk will include simulation results, as well as the development of the City-LES model.