The ENVI-met Model Sample Clauses

The ENVI-met Model. The ENVI-met model was used to simulate microclimatic variables during the period of the measurements. This is a three-dimensional non-hydrostatic microclimate model developed to calculate and simulate climate variables and pollutant dispersion in urban areas with a typical grid resolution of 0.5 to 10 meters and a timestep of up to 10 seconds. It models the evolution of the output variables during diurnal cycles using fundamental laws of fluid dynamics and thermo dynamics. The model considers direct, reflected and diffused solar radiation. The presence of vegetation is considered in the radiative fluxes including shading, absorption and also re-radiation. The ENVI-met software uses input values for buildings, vegetation, surfaces characteristics, soils, climatic conditions and pollutant emissions. The integration of all the different submodules in a CFD model increases the computational costs. The vegetation module in ENVI-met describes the plants as porous elements characterized by LAD (Leaf Area Density, m2/m3). It is included in the momentum and turbulent kinetic energy equations. Considering the period of the measurements (i.e. from sunrise to sunset), simulations were launched at 4:00 local time (i.e. UTC+2), i.e. approximately 3 hours before sunrise. The background air flow characteristics that forced the model where taken from Deusto station from the Basque Meteorological Network. The total modelling time was 20 hours which included the period when measurements were carried out. Discrete receptors were defined in the model for the locations of the measurements. For these, output climate values of the model every 30 minutes were available. For the whole grid, outputs were recorded every hour. Characteristics of the model dimensions in each area are given in Table 12. Table 13 shows a representation of the location of buildings and vegetation. The meteorological boundary conditions during each day of campaign considered in the modelling are in Table 14. Figure 31 shows Ta and RH hourly evolution introduced to the model. Wind speed (WS) and direction (WD) of the air flow affecting the model area was considered constant during the whole modelling period due to model limitations. An adequate value of WS and WD was considered for each simulation period taking into account the air flow during daytime when the sea breeze was well established (i.e. 9:00 -19:00 UTC). RiberaDeusto Miribilla CascoViejo Indautxu