Atmospheric parameters affecting SPectral solar IRradiance and solar Energy (ASPIRE)

The ASPIRE project aims to contribute to the scientific knowledge of interdisciplinary aspects that are related with solar radiation by investigating the effect of various atmospheric parameters such as clouds, aerosols, water vapor and absorbing trace gases to the Spectral Solar Irradiance (SSI) reaching the Earth’s surface. Such aspects deal with solar energy research and technology (e.g. Photovoltaic Systems, PV), impact on health (melanoma, skin cancer and Vitamin D efficiency), agriculture (photosynthetically active radiation, PAR, and crop production) and the complexity of the SSI determination through an atmosphere with various spectral absorbing, scattering and reflecting atmospheric constituents.

The project has four specific objectives: (a) To investigate the effect of atmospheric composition in different solar spectral regions, (b) To assess the impact of atmospheric composition on UV Index, Vitamin D and PAR, (c) To improve PV efficiency based on spectral solar data for various atmospheric composition cases, (d) To evaluate the performance of the Solar Energy Nowcasting SystEm (SENSE) using real solar spectra. The means to fulfil these objectives is a sophisticated atmospheric field experiment that has been held in the city of Athens, Greece, with a unique set of instrumentation and a synergistic approach on the retrieved datasets. Atmospheric composition and solar radiation related measurements and models are coordinated in ASPIRE in order to contribute to the following scientific advancements:

• Accuracy of public awareness solar radiation related factors, such as erythemal (UV Index), eye cataract, DNA damage, Vitamin D production and agricultural (PAR) related indexes, could be essentially improved using the proposed measurements’ dataset.
• PV efficiency will be assessed and improvements will be suggested, with the use of detailed spectral information that will be available. In addition, atmospheric variables that attenuate SSI will be linked with possible deviations of the PV output. ASPIRE will provide to PV module users and constructors the know-how to link individual atmospheric solar attenuators (e.g. aerosols and trace gases) to such deviations.
• Solar energy nowcasting is a crucial aspect for national and private power transmission and distribution system operators worldwide. Detailed evaluation and improvement of such a developed system for Greece is an important aspect of the project, given the fact that the proposed SENSE system has been used by the national energy transmission operator.