School Students participation in monitoring solar radiation components: Preliminary results for UVB and UVA solar radiant fluxes

摘要

As the planet is experiencing dramatic environmental problems mainly due to human activities, education plays an essential role in the formation of pupils' attitudes toward the environment, both social and natural. That is, the depletion in the concentration of ozone layer in the stratosphere significantly increases the UV radiant flux levels (mainly the part of UVB, from about 290-315 nra) reaching the earth's surface. These modifications have raised concern among the scientists and policy makers during the last two decades so that numerous field experiments have been conducted illustrating deleterious UVB effects on both ecosystems and human beings. Indeed, in recent years, the ultimate action of education is to sensitize the pupils as well as the public toward environmental problems laying the foundations for both students' and citizens' active participation in the protection of the environment. This article presents students' results dealing with solar ultraviolet radiant fluxes obtained through school's solar radiation monitoring-networks, which have been established over the broader Thrace-Aegean-Cyprus belt, during 2005. Students' measurements of global and diffuse UVB (G_(h-uvb). G_(d-uvb)). UVA (G_(h-uva). G_(d-uva)) and broadband (Gh, Gd) radiant fluxes are used to explore the relationship between these radiant fluxes over the three sites considered. The analyses of the available data sets revealed that a linear correlation between global G_(h-uva) and G_h radiant fluxes exists, whereas the correlation between global Gh-uvb and G_h radiant fluxes was well described by a quadratic equation. The variation of the hourly precise ratios (slope a = G_(h-uva)/G_h) ranges from 0.0301 ± 0.005 in Acropolis, Cyprus to 0.0286 ± 0.006 in Alexandroupolis, Thrace, while the ratios (G_(h-uvb)/Gh) exhibited similar variability, with high values in Acropolis (0.00210 ± 0.0005) and low values (0.00197 ± 0.0007) in Alexandroupolis. The hourly ratios for the diffuse radiant components (G_(h-uva)/Gd) and (G_(h-uvb)/Gd) were found to range from 0.0486 ± 0.005 and 0.00431 ± 0.0005 in Acropolis to 0.0452 ± 0.008 and 0.00397 ± 0.0006 in Alexandroupolis, respectively. Using further the data set of the Acropolis site, an inverse correlation between the daily ozone column amount and the precise G_(h-uvb)/G_h ratio was found, which can be rather attributed to changes of various atmospheric parameters than the ozone column. Finally, through the data set of Acropolis site, seasonal trends of the UV-index as well as the effect of solar eclipse of 29 March 2006 on the UV radiant components are discussed.