Effect of sea breeze propagation on the urban boundary layer of the metropolitan region of Sao Paulo, Brazil

Autor(es)

Ribeiro, Flavia N. D. ^[1] ; de Oliveira, Amauri P. ^[2] ; Soares, Jacyra ^[2] ; de Miranda, Regina M. ^[1] ; Barlage, Michael ^[3] ; Chen, Fei ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Arts Sci & Humanities, Av Arlindo Bettio 1000, BR-03828000 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Rua Matao 1226, BR-05508090 Sao Paulo, SP - Brazil

^[3] Natl Ctr Atmospher Res NCAR, 3450 Mitchell Lane, Boulder, CO 80301 - USA

• Tipo de documento: Artigo Científico
• Fonte: ATMOSPHERIC RESEARCH; v. 214, p. 174-188, DEC 1 2018.
• Citações Web of Science: 6

Resumo

Thermally driven circulations over urban areas, such as sea, lake, and land breezes and mountain-valley and urban heat island (UHI) circulations, strongly determine local weather and air quality conditions over highly populated areas. This study investigates the influence of sea breeze (SB) propagation on the development of the urban boundary layer (UBL) in the Metropolitan Region of Sao Paulo (MRSP), Brazil, an urban area with complex topography. This investigation is undertaken observationally by analyzing surface and upper air observations conducted in 2013 during the MCITY BRAZIL Project field campaigns and is conducted numerically by performing a set of Weather Research and Forecasting (WRF) simulations. The observational analysis highlights two SB events in the MRSP, one in February (austral summer) and the other in August (winter). In both seasons, the passage of the SB front disrupts the convective growth of the UBL and establishes a thermal internal boundary layer, thereby reducing the UBL height. The cooling also momentarily disrupts the UHI circulation. The results indicate that topography enhances SB propagation because it helps the marine air to go up the MRSP coastal escarpment and to reach the plateau while forcing adiabatic cooling of this air, intensifying the thermal gradient between the southern part of the plateau and the urban area. The UHI further increases the thermal gradient (from 0.5 K to 2 K in summer and 1 to 2.5 K in winter), accelerating the SB propagation. Synoptic conditions determine whether the SB front reaches the urban area and also may displace the convergence center of the UHI circulation. (AU)

• Processo FAPESP: 14/04372-2 - Influência da circulação de brisa marítima no desenvolvimento da CLP e implicações para a qualidade do ar na RMSP
• Beneficiário: Flávia Noronha Dutra Ribeiro
• Linha de fomento: Auxílio à Pesquisa - Regular