TOWARDS THE IMPLEMENTATION OF THE WRF-CHEM MODEL IN BUENOS AIRES

ANDREA PINEDA ROJAS; FELIX CARRASCO; HORACIO BOGO; JUAN RUIZ

Fort Collins

Congreso; 9th International Congress on Environmental Modelling and Software; 2018

Colorado State University

The WRF-Chem model is implemented in the Metropolitan Area of Buenos Aires (MABA)for the first time. In order to determine the best model configuration representing transport anddispersion within the planetary boundary layer (PBL), several simulations are performed consideringdifferent PBL schemes (YSU, MYJ, QNSE, MYNN and MYNN3) and horizontal resolutions (1 km and5-km). An analysis of its performance to simulate carbon monoxide (CO) concentrations at a greenurban site and relevant atmospheric variables (air temperature, wind speed and direction) ispresented. Four 5-day-periods are selected covering different seasons of the year. All simulations areperformed in a 330 km x 305 km domain considering 38 vertical levels, the Noah LSM and the MODISland use data. Meteorological initial and boundary conditions come from the Climate ForecastReanalysis System. CO emissions belong to a high resolution emission inventory developed for theMABA. The sensitivity of model results to the choice of the PBL scheme is studied considering a 5 kmhorizontal resolution. Atmospheric variables are well simulated by the five schemes. Statisticalcomparison between modelled and observed hourly CO concentrations shows that there is no singlePBL scheme that performs best for all measures and seasons. MYNN, QNSE and YSU present betterstatistics in autumn, winter and spring, respectively. When horizontal resolution is increased to 1 km,no clear improvement is observed. The modelled CO peak concentration can be lower or greater thanthat obtained with the 5 km resolution simulation, highlighting the role of changes in variables otherthan emissions.