Scientists from the Laboratory of Atmospheric Physics (Department of Physics, Aristotle Univ. of Thessaloniki) have investigated the changes of the solar UV irradiance in the present (mean levels for the period 2005-2015) and in the future (mean levels for the period 2090-2100) compared to the past (mean levels for the period 19501960). The study was focused mainly in the Arctic and the subArctic Oceans. The derived changes in UV irradiance were attributed to the corresponding changes in the surface reflectivity, the total ozone column and the cloudiness. The projected levels of the UVB irradiance, the UVA irradiance and the UV index on the surface and of the UVB irradiance that is transmitted into the ocean were quantified.
The spectral solar irradiance reaching the Earth’s surface was calculated using the cdisort, pseudospherical approximation (Buras et al., 2011) of the radiative transfer model UVSPEC, which is included in the version 1.7 of the libRadtran package (Mayer and Kylling, 2005). The simulations were based on inputs from four EarthSystem Models, which participated in the fifth phase of the Coupled Model Intercomparison Project (CMIP5) (Taylor et al., 2011), and on climatological data for aerosols (Kinne et al., 2013). Simulations were performed for a standard 10°×2.5° (longitude × latitude) grid and for two different socioeconomic scenarios, corresponding to different GHGs emissions in the future.
Results of this study suggest that, for specific months and grid cells, the monthly mean UV index on the surface can be up to 40% lower in the future compared to the past (figure 1), while the monthly mean UVB that enters the ocean can be up to 10 times higher (figure 2).
A large part of the simulations was performed using on the EGI and the HellasGrid infrastructures with the support provided by the Scientific Computing Services Office at the Aristotle University of Thessaloniki. In the researchers’ own words:
“Using these resources enabled us to drastically limit the time required for the simulations.”
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- Fountoulakis I., Bais, A. F., Tourpali, K., Fragkos, K., and Misios, S. (2014), Projected changes in solar UV radiation in the Arctic and sub-Arctic Oceans: Effects from changes in reflectivity, ice transmittance, clouds, and ozone, J. Geophys. Res. Atmos., 119(13), 8073–8090, doi: 10.1002/2014JD021918
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