UltraViolet Irradiance Variability in Arctic
It is well known that besides the stratospheric ozone UV irradiance, reaching the ground depends strongly on various environmental conditions such as surface reflectance, clouds, aerosols etc. that make the variability of the UV irradiances over different regions of the Earth to have specific features. Taking into account the importance of UV radiation for atmospheric photochemistry and biosphere it is considered that the knowledge about the variations of this solar spectrum component is extremely significant.
The Arctic is a crucial region with regard to its impact on the planet climate so that the study of UV irradiance variability here is considered to be substantial task. This is the main problem of the present project. Using the multifilter UV radiometer UV-RAD, developed at ISAC-CNR on the basis of narrow-band filters, the variability of UV irradiance is planned to be investigated. The instrument measures the UV irradiance at seven channels each of them having around 1 nm full width at half maximum that allows to reconstruct the solar UV spectrum (290-400 nm) with 1 nm resolution. Thus, the instrument gives the information about various components of surface solar UV irradiance. In addition, total ozone amount can be defined using the UV-RAD measurements. It is expected that the results provided by the radiometer will give the information about: (i) impact of the specific surface reflectance changes at Svalbard, presenting relief, characterised by varying snow covered and free water surfaces combined with mountains, on the surface UV irradiance; (ii) influence of the Arctic cloud cover features on the UV radiation; (iii) how UV irradiance depends on atmospheric dynamics that present particular characteristics in the Arctic atmosphere and (iv) studying of the variations of total ozone in the north polar region. The responses of all these problems obtained from the UV-RAD measurements that is planed to be compared with the other similar instruments based at Ny-Ålesund can help us to understand the variability features of the ground UV irradiance and to connect them with the local climate characteristics.