Revista Brasileira de Meteorologia (Nov 2020)

Analysis of Measurements of Direct Normal and Global Solar Radiation for Maceió, Alagoas State, Northeastern Brazil

  • José Marcelo Lopes Júnior,
  • José Leonaldo de Souza,
  • Ricardo Araujo Ferreira Junior,
  • Cícero Manoel dos Santos,
  • Gustavo Bastos Lyra,
  • Chigueru Tiba,
  • Rosiberto Salustiano da Silva Júnior

DOI
https://doi.org/10.1590/0102-77863540070
Journal volume & issue
Vol. 35, no. 4
pp. 659 – 674

Abstract

Read online Read online

Abstract Studying solar radiation is essential for human knowledge, since it is present in practically all its activities. Thus, the aim of this work was to analyze the climatic and seasonal variation of direct normal and global solar radiation in the region of Maceió, Alagoas State, Northeastern Brazil with sky conditions characterized by clearness index (Kt). The Kt was determined by the ratio between global solar irradiance and solar irradiance at the top of the atmosphere. The highest occurrences of daily direct normal solar irradiance under conditions of Kt ≥ 0.6 were recorded between 400 W m−2 and 700 W m−2 for all seasons. Under conditions of 0.4 ≤ Kt < 0.6, the daily direct normal solar irradiance occurred between 200 W m−2 and 500 W m−2 and for conditions of Kt < 0.4, its maximum value was 200 W m−2. It was observed that the levels of solar incidence in the study region depend on cloud cover conditions, with little influence of seasonality.

Keywords