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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Author(s):
Yamasoe, Marcia Akemi [1, 2] ; Evora Rosario, Nilton Manuel [3] ; Santos Martins Almeida, Samantha Novaes [2] ; Wild, Martin [4]
Total Authors: 4
Affiliation:
[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
Total Affiliations: 4
Document type: Journal article
Source: Atmospheric Chemistry and Physics; v. 21, n. 9, p. 6593-6603, MAY 3 2021.
Web of Science Citations: 0
Abstract

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)

FAPESP's process: 18/16048-6 - The cloud effect on the surface radiation budget at São Paulo Megacity
Grantee:Márcia Akemi Yamasoe
Support Opportunities: Research Program on Global Climate Change - Regular Grants