Airborne UV/Vis actinic measurements in the lower Antarctic stratosphere

The present work deals with UV/Vis up-welling and down-welling irradiation measurements carried out in the lower Antarctic stratosphere by means of GASCOD-A/4pi spectroradiometer on board the M55-Geophysica aircraft during the APE-GAIA campaign. Very few such measurements have been performed in the lower stratosphere. The experimental data are used for the calculation of NO2 photodissociation rate coefficients in the upper troposphere and lower stratosphere along the altitude of the flight. A detailed description of the measurement method, instrumentation and calibration procedures is presented. Experimental results are presented and discussed too.