Short-term variations in surface UV-B irradiance and total ozone column at Ny-Ålesund during the QAARC campaign

Abstract

Diurnal variations in total ozone column were observed to exceed 40DU during the QAARC campaign of late spring 2009 held at the Ny-Ålesund Arctic station in Svalbard. They were correlated to corresponding oscillations of surface UV-B irradiance, assuming that the strong dependence between these two variables ensures the reliability of registered total ozone oscillations. To make the comparison, an approach is proposed that allows the retrieval of diurnal variability in UV-B irradiance due to total ozone column changes, for application to the data collected during the campaign. The UV irradiance features observed with the reference spectroradiometer over a 7-day period were analyzed together with the corresponding ozone column data-sets, simultaneously obtained using two different devices. Power curves were found to provide the best-fit solutions for the retrieved UV-B variations, examined as a function of total ozone variations. Such approximations are characterized by regression coefficients of about −0.94 and by the exponent named in earlier studies as the radiation amplification factor (RAF), which was found to vary between 0.79 and 2.49. These RAF evaluations are in good agreement with previous estimates derived from both field measurements and model evaluations, which confirm the complete dependability of the short-term variations in the ozone column measured at Ny-Ålesund.