Marcelo Raponi

NO2 Vertical Column Density at the Marambio Antarctic Station as Retrieved by DOAS

A number of chemical species present in the stratosphere in very small concentrations (parts per billion and even smaller) contribute significantly to its chemical balance. One of the main stratospheric trace gases is nitrogen dioxide (NO2). This species acts as a restrictive agent for stratospheric ozone destruction (due to the chlorine monoxide), hence the importance of its study. We present a preliminary analysis of passive remote sensing measurements carry out at the Marambio Argentinean Antarctic Base (64.233° S; 56.616° W; 197 m amsl) during the months of January—February of 2008. The spectroscopy system consists of an optical fiber (400 μm core diameter and 6 m of longitude) and a portable spectral analyzer (spectrometer HR4000, Ocean Optics). The device analyzes diffuse solar spectral irradiance in the UV‐visible range (290–650 nm), collected and transferred by a zenith‐pointing optical fiber. The NO2 vertical column density (VCD) is derived from the radiance spectra using the DOAS (Differential O...

Stratospheric NO2 Concentration Determined by DOAS Using Compact Spectrographs

In this work we present the results for stratospheric NO2‐total column concentration retrieved by DOAS (Differential Optical Absorption Spectroscopy) performed with compact spectrographs. The behavior for three different spectrographs (MonoSpec 27, Jarrell‐Ash; HR4000, Ocean Optics and Mechelle 900, Multichannel Instruments) are analyzed making one intercomparison in the facilities of the LIDAR Division of CEILAP (CITEFA—CONICET), in Villa Martelli, Argentina (34.5° S, 58.5° W, 20 m amsl). The three instruments have a similar resolution (approximately 0.1 nm) but operate with different optical configurations and have optical sensors of different characteristics; two of them have cooling capability and the other one (HR4000) operates at room temperature. The NO2 concentration was obtained from spectral results at twilight using solar noon spectra as reference. In all cases zenithal diffuse irradiance was used. The NO2 absorption cross section given by S. Voigt and J. P. Burrows (University of Bremen—Instit...

Using Lidar to Measure the Ozone Layer

South American scientists are using lidar technology to measure stratospheric ozone, water vapor and aerosols in Argentine Patagonia. Their work is helping to monitor global climate change, and has led to the development of a method for alerting local populations to the presence of the ozone hole.