The aim of this study was to applied the regression analysis results in order to estimate the solar global radiation as a function of the insolation at Macapa City (AP), this being an alternative to the weather stations that has no records of the global solar radiation. Daily data for the twelve months of the year were used, in the period 2006-2012, of radiation observed in Data Collection Platform (PCD) of the Instituto Nacional de Pesquisas Espaciais (INPE) and insolation from the conventional station of the Instituto Nacional de Meteorologia (INMET) from Brazil. The estimation of global solar radiation with insolation was performed using simple linear regression equations and the Angström-Prescott model. The monthly Pearson correlation coefficients (r) analyzed proved satisfactory (0.76 and 0.82); the highest monthly values of the coefficients "b" of the Angström-Prescott equation were found in the rainy season (summer) (b = 0.45; 0.44), indicating that the diffuse solar radiation is higher at this time of year than during the driest months, probably due to aerosols and clouds in the atmosphere. Therefore, with the high ratio between this meteorological elements studied, the global radiation estimated from the insolation can be used for Macapá (AP).
photoperiod; solar radiation ratio; insolation ratio
