This research shows equations of evaluation of global solar irradiation (GR) through Angstrom's model with seasonal monthly partitions for the region of Cascavel -PR, Brazil. The experimental data were given by IAPAR and collected in its meteorological station located in COODETEC/Cascavel - PR, Brazil, from 1983 to 1998. Twelve of the sixteen years of data were used for calculation of the coefficients (a and b) and four years for the validation of the equations. The determination coefficients found were superior to 80% for both partitions. The minimum (GR) is overestimated and the maximum is underestimated when compared to the minimum and maximum for real data, been these found in the winter solstice and spring equinox, respectively. The seasonal and monthly variation of the coefficient "a" was lower (0.16 to 0.19 and 0.14 to 0.21) and the variation for the coefficient "b" was higher (0.34 to 0.43 and 0.32 to 0.44). The highest variations of daily average errors had occurred in the spring equinox (-19.45% to 27.28%) and the lowest ones in the autumn equinox (-11.32% to 10.61%). The most efficient adjustment of the equation was found for the monthly partition.
actinographer; heliographer; model of Angstrom
