Abstract

The aim of this study was to evaluate the effect of environmental dirt on the global irradiation measurement equipment installed in a weather station in the city of Arica, Chile, as well as characterizing the content of the settleable particulate material deposited on the station. Since it was not possible to use two pyranometers simultaneously in the elaboration of this research, the first step was to obtain a model of global irradiation using the other data available from the weather station as input variables. Calculating global irradiation by adding the direct and diffuse components is an effective method (4.5% average error), although the use of a polynomial equation allows this error to be reduced (3.5% average error). It was observed that the error in the measurement is related to the irradiation level and the presence of three characteristic zones: (i) when irradiance is below 50 W/m2 the largest errors are present (ii) when irradiance is between 50 and 500 W/m2 the error increases as irradiance increases (iii) above 500 W/m2 the error stabilizes in the region of 5-6%. In addition, it was determined that the effect of dirt is negligible during the first 7 days. The minerals present in greatest proportions were identified as: Halite, Gypsum, Quartz, Albite, Anorthite and Anhydrite. All these minerals appear to be originate from natural sources of contamination such as the proximity to the Pacific Ocean and the desert conditions in the area. No mineral that may be associated with anthropogenic sources was found in any great quantity.