Implementing WUDAPT in Metropolitan Area of Sao Paulo in Brazil: Influence of Urban Area in the Meteorological Simulations Using WRF Model

Implementing WUDAPT in Metropolitan Area of Sao Paulo in Brazil: influence of urban area in the meteorological simulations using WRF model.

 

Dirce Maria Pellegatti FRANCO^1,2, Maria de Fatima ANDRADE¹ and Mario Eduardo Gavidia CALDERON¹

1. Department of Atmospheric Sciences, Institute of Astronomy, Geophysics, and Atmospheric Sciences, University of Sao Paulo, Sao Paulo, Brazil
2. Meteorological Sector, Air Quality Division, Sao Paulo State Environmental Agency (CETESB), Sao Paulo, Brazil

Abstract: The Metropolitan Area of Sao Paulo (MASP) is the main urban center of South America, occupying the sixth position among the largest in the world, according to the United Nations (UN) report in 2014. It has about 21 million inhabitants spread over an area of 7,947 km². As effect of urbanization, complex interactions with atmospheric mesoscale circulations can influence local circulation patterns. The mobile source is responsible by the emissions of gaseous and particles involved in the formation of secondary pollutants, as ozone and PM2.5 that present concentrations above the air quality standards. The air quality simulations through Chemical Transport Models (CTM) are important to understand the physic-chemistry process of formation of these pollutants.

The representation of the micro-scale processes in the mesoscale models is a challenge due to the inhomogeneity of the surface and local characteristics of each urban area in the world.

Many studies regarding the formation of pollutants in MASP are being performed with the application of WRF-Chem (Weather and Research Forecasting with Chemistry) and the simulations showed that it is necessary to improve the representation of the surface characteristics. In order to study the impact of using different micrometeorological parameterizations, simulations were generated to MASP through the WRF model considering three nested grids with resolution of 9, 3 and 1 km, centered on lat 23°33’S and long 45°W englobing an area of 78 x 51 km (finer grid). It was considered three urban surface parameterization in the simulations: default; single-layer and muiti-layer Building Environment Parameterizaton (BEP). Concerning the Planetary Boundary Layer (PBL) schemes, it was used MYJ and Boulac parameterization. For the simulation with BEP, only in the finer grid resolution (1km), it was considered ten built types of Local Climate Zone (LCZ) classification (Stewart & Oke, 2012), obtained through Google Earth and Saga images as acquisition data strategy level "0" of WUDAPT. Simulated results for temperature and wind speed at surface and altitude were compared with data measured at air quality monitoring stations of the Sao Paulo State Environmental Agency (CETESB) and with meteorological soundings obtained in a monitoring campaign from 28 October to 1 November 2006.

Key words: Local Climate Zone (LCZ) Classification, World Urban Database and Access Portal Tools (WUDAPT), WRF, Metropolitan Area of Sao Paulo.

(*This abstract is preferred to be submitted to the special WUDAPT session)