Determination of the seasonal variation of the nitrogen dioxide and ozone vertical column density at Río Gallegos, Santa Cruz province, Argentina, using a zenith-sky DOAS system

Abstract

Stratospheric ozone (O3) plays a critical role in the atmosphere by absorbing most of the biologically damaging solar UV radiation before it reaches the Earth's surface. Nitrogen dioxide (NO2) is a key trace gas in the ozone photochemical. The systematic sensing of NO2 and other minority gases is essential in order to understand the stratospheric O3 destruction and formation processes. We present the study carried out on the seasonal variation of the O3 and NO2 vertical column density (VCD), using a zenith-sky DOAS (Differential Optical Absorption Spectroscopy). This system is composed of a spectral analyzer (portable spectrometer HR4000, Ocean Optics), two optical fibers (400 µm of core, 25 cm and 6 m of longitude) and an automatic mechanical shutter. NO2 and O3 VCD are derived from solar spectra acquired during twilights (87° - 91° zenithal angles). The data retrieved by our instrument are compared with those coming from the SAOZ spectrometer (Systeme d'Analyse par Observation Zenithale, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), France). Both systems are located in Rio Gallegos, Santa Cruz province, Argentine (51° 36' S; 69° 19' W, 15 m asl), in the CEILAP-RG remote sensing station.

Stratospheric ozone (O3) plays a critical role in the atmosphere by absorbing most of the biologically damaging solar UV radiation before it reaches the Earth's surface. Nitrogen dioxide (NO2) is a key trace gas in the ozone photochemical. The systematic sensing of NO2 and other minority gases is essential in order to understand the stratospheric O3 destruction and formation processes. We present the study carried out on the seasonal variation of the O3 and NO2 vertical column density (VCD), using a zenith-sky DOAS (Differential Optical Absorption Spectroscopy). This system is composed of a spectral analyzer (portable spectrometer HR4000, Ocean Optics), two optical fibers (400 µm of core, 25 cm and 6 m of longitude) and an automatic mechanical shutter. NO2 and O3 VCD are derived from solar spectra acquired during twilights (87° - 91° zenithal angles). The data retrieved by our instrument are compared with those coming from the SAOZ spectrometer (Systeme d'Analyse par Observation Zenithale, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), France). Both systems are located in Rio Gallegos, Santa Cruz province, Argentine (51° 36' S; 69° 19' W, 15 m asl), in the CEILAP-RG remote sensing station.