Dr. Gonzalo Abal, Facultad de Ingeniería
The Solar Energy Laboratory maintains a network of continuous measurement of solar irradiance of high quality that today has eight stations distributed in the territory of Uruguay (http://les.edu.uy). The data of this network are used to adjust our satellite models and allow a characterization of the solar resource in any point of the territory.
This project aims to characterize the solar irradiance incident on the BCAA during the austral summer, for which will be mounted a measuring station specially designed to withstand the prevailing climatic conditions. Solar irradiance on the horizontal plane will be recorded in a redundant form (two measurements of GHI, broadband between 300 and 3000 nm) and ultraviolet solar UV irradiance in bands A (315-400 nm) and B (280-315 nm). The UV index will also be released. These measures will be carried out at intervals of 1 minute between December and April. The information generated will allow us to characterize the solar irradiance in the BCAA during the summer months and integrate it into future versions of the Solar Map of Uruguay.
Ultraviolet irradiation accounts for about 8% of solar radiation, and is receiving increasing attention because of its potential impact on living things and the degradation of plastics and other materials. Atmospheric ozone absorbs most of the UVB radiation and it is possible to estimate the thickness of the ozone column from simultaneous measurements of UVA and UVB. The counting of measurements in the Antarctic is of particular interest to be in the zone of influence of the attenuation of the ozone layer. In addition, by simultaneously measuring UV and GHI we can correlate the UV irradiance with GHI measurements and verify if the correlations used in the continent are still valid in BCAA conditions. This correlation will allow us to estimate UV irradiation at all points in the territory where GHI is measured and to generate information on the average spatial distribution of UV irradiation in Uruguay.
Finally, the use of clear sky models allows GHI to be estimated with high precision if the state of the atmosphere is known. This estimation is important for fine quality control of measured data on the ground and also as a basis for physical models of solar irradiance, in which the effects of cloudiness observed by satellite are included a posteriori. An especially simple clear sky model is the single-parameter ESRA model, the Linke turbidity [Ri00] which characterizes the amount of aerosols and water vapor present in the atmosphere. We have developed a method to estimate Linke turbidity (TL) indirectly from GHI soil measurements and have characterized the seasonal and geographic variability of TL on the Uruguayan territory. This study will also be conducted in the BCAA, where the influence of aerosols is expected to be almost nil. Once adjusted in this way, the clear sky model can be used as a quality control tool for ground data, as well as being the basis for a physical model of solar irradiance.