Fifty-six years of surface solar radiation and sunshine duration over Sao Paulo, Brazil: 1961-2016

Autor(es)

Yamasoe, Marcia Akemi ^{[1, 2]} ; Evora Rosario, Nilton Manuel ^[3] ; Santos Martins Almeida, Samantha Novaes ^[2] ; Wild, Martin ^[4]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Ciencias Atmosfer, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Secao Serv Meteorol, Inst Astron Geofis & Ciencias Atmosfer, Sao Paulo, SP - Brazil

^[3] Univ Fed Sao Paulo, Dept Ciencias Ambientais, Diadema, SP - Brazil

^[4] Swiss Fed Inst Technol, Inst Atmospher & Climate Sci, Zurich - Switzerland

• Tipo de documento: Artigo Científico
• Fonte: Atmospheric Chemistry and Physics; v. 21, n. 9, p. 6593-6603, MAY 3 2021.
• Citações Web of Science: 0

Resumo

A total of 56 years (1961-2016) of daily surface downward solar irradiation, sunshine duration, diurnal temperature range and the fraction of the sky covered by clouds in the city of Sao Paulo, Brazil, were analysed. The main purpose was to contribute to the characterization and understanding of the dimming and brightening effects on solar global radiation in this part of South America. As observed in most of the previous studies worldwide, in this study, during the period between 1961 and the early 1980s, a negative trend in surface solar irradiation was detected in Sao Paulo, characterizing the occurrence of a dimming effect. Sunshine duration and the diurnal temperature range also presented negative trends, in opposition to the positive trend observed in the cloud cover fraction. However, a brightening effect, as observed in western industrialized countries in more recent years, was not observed. Instead, for surface downward irradiation, the negative trend persisted, with a trend of -0.13 MJ m(-2) per decade, with a p value of 0.006, for the 56 years of data and in consonance with the cloud cover fraction increasing trend, but not statistically significant, of 0.3% per decade (p value = 0.198). The trends for sunshine duration and the diurnal temperature range, by contrast, changed signal, as confirmed by a piecewise linear regression model. Some possible causes for the discrepancy are discussed, such as the frequency of fog occurrence, urban heat island effects, horizontal visibility (as a proxy for aerosol loading variability) and greenhouse gas concentration increase. Future studies on the aerosol effect are planned, particularly with higher temporal resolution, as well as modelling studies, to better analyse the contribution of each possible cause. (AU)

• Processo FAPESP: 18/16048-6 - Efeito das nuvens no balanço de radiação em superfície na megacidade de São Paulo
• Beneficiário: Márcia Akemi Yamasoe
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular