Exploratory Environmental Science Research

Volume 1 - Issue 1 - 2020

Original Research Article

Assessing Urban Effects On The Climate Of Metropolitan Regions Of Brazil - Preliminary Results Of The MCITY BRAZIL Project

Amauri Pereira de Oliveira1*, Edson Pereira Marques Filho2,3, Maurício Jonas Ferreira1,
Georgia Codato1, Flávia Noronha Dutra Ribeiro1, Eduardo Landulfo4, Gregori de Arruda Moreira4,5, Maxsuel Marcos Rocha Pereira6, Primoz Mlakar7,
Marija Zlata Boznar7, Eleonora Sad de Assis8, Daniele Gomes Ferreira8, Mariana Cassol2,3,
João Francisco Escobedo9, Alexandre Dal Pai9, José Ricardo de Almeida França2, Demilson Assis Quintão10,
Flávia Dias Rabelo1, Luana Antunes Tolentino Souza1, Wallace Pereira da Silva2, Leonardo Moreno Domingues1,
Maciel Piñero Sánchez1, Lucas Cardoso da Silveira1, Janet Valdes Vito1

1University of São Paulo (USP), São Paulo, SP, (BRAZIL)
2Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, (BRAZIL)
3Federal University of Bahia (UFBA), Salvador, BA, (BRAZIL)
4Institute of Nuclear Energy Research (IPEN), São Paulo, SP, (BRAZIL)
5Federal Institute of São Paulo (IFSP), Registro, SP, (BRAZIL)
6Federal University of Espírito Santo (UFES), Vitória, ES, (BRAZIL)
7MEIS d.o.o. (MEIS), Ljubljana, (SLOVENIA)
8Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, (BRAZIL)
9State of São Paulo University (UNESP), Botucatu, SP, (BRAZIL)
10State of São Paulo University (UNESP), Bauru, SP, (BRAZIL)

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ABSTRACT - DOI : https://dx.doi.org/10.47204/EESR.1.1.2020.038-077

This work describes the MCITY BRAZIL Project. The project designed to assess urban effects on the climate of the major Brazilian cities and to systematize this procedure of investigation so it can be extended to other urban areas in Brazil. In this article, the implementations in the Metropolitan Regions of São Paulo and Rio de Janeiro are presented. A preliminary description of the surface radiation balance, surface energy balance, surface wind pattern, urban heat island and urban boundary layers are discussed by considering the surface observations carried out in the MCITY BRAZIL project from 2013 to 2014 in four micrometeorological towers in these two metropolitan regions. Despite nearly identical inputs of solar radiation at the top of the atmosphere, differences in the atmospheric attenuation and emissions, and in the surface albedo and emissions resulted in significant differences in surface radiation balance components between metropolitan regions and within each urban area. The diurnal evolution of the surface energy balance, friction velocity and carbon dioxide vertical fluxes observed during the field campaigns indicate important seasonal and spatial variations associated with the land use in both urban regions. Surface wind analyses for both metropolitan regions display similar seasonal and diurnal patterns as a result of the combination of large-scale systems and sea-breeze circulation present in both regions and modulated by topography. The urban heat island in São Paulo is greater than that in Rio de Janeiro as a result of different combinations of maritime and solar heating effects. The diurnal evolution of the urban boundary layer height and surface inversion layer top estimated simultaneously by rawinsonde and Lidar displays good agreement in both metropolitan regions. In São Paulo, daytime urban boundary layer height responds to the sensible heat flux at the surface. In Rio de Janeiro, despite of equivalent sensible heat flux, urban boundary layer is smaller due to the internal maritime boundary layer effects.