Annual and Monthly Average Global, Direct and Diffuse Solar Radiation in Botucatu/SP/Brazil
Abstract
: This paper presents a climatic and statistical analysis of global, direct horizontal and diffuse radiation from a database of solar radiation measured from 1996 to 2006 in the city of Botucatu, SP, Brazil. Variation intervals of hourly and daily irradiation, annual mean <H̅ G>, <H̅ bh> and <H̅ d> irradiation, monthly mean <H̅ G>, <H̅ bh> and <H̅ d> irradiation and monthly mean <K̅ t>, <K̅ bh> and <K̅ d> fractions were determined. Results showed that values of hourly and daily annual mean irradiation were as follows: <H̅ G>=1.49MJ/m2 and <H̅ G>=17.74MJ/m2; <H̅ bh>=0.90MJ/m2 and <H̅ bh>=10.33MJ/m2 and <H̅ d>=0.57 MJ/m2 and <H̅ d>=7.09MJ/m2, respectively. Variation intervals of hourly monthly mean irradiation were as follows: <H̅ G> ranged from 1.65MJ/m2 in March to 1.16MJ/m2 in June; <H̅ bh> ranged from 1.06MJ/m2 in April to 0.79MJ/m2 in June, and <H̅ d> ranged from 0.70MJ/m2 in January to 0.37MJ/m2 in June and July. Similarly, daily <H̅ G> irradiation ranged from 21.35MJ/m2 in November to 12.94MJ/m2 in June; <H̅ bh> ranged from 11.83MJ/m2 in April to 8.49MJ/m2 in June, and <H̅ d> ranged from 10.29MJ/m2 in December to 4.38MJ/m2 in June. Variation intervals of hourly monthly mean fractions were as follows: <K̅ t> ranged from 43.5% in January to 54.2% in April; <K̅ bh> ranged from 33.6% in January to 58.0% in April and <K̅ d> ranged from 66.4% in January to 42.0% in April. In the same way, daily <K̅ t> fractions ranged from 45.5% in January to 59.8% in August; <K̅ bh> ranged from 38.9% in January to 62.0% in August and <K̅ d> ranged from 61.1% in January to 37.7% in July.