Monitoring of atmospheric compounds at high latitudes is a key factor for a better understanding of the processes driving
the chemical cycles of ozone and related chemical species. In this frame, the GASCOD (Gas Analizer Spectrometer
Correlating Optical Differences) equipment is installed at the Mario Zucchelli Station (MZS - 74.69S, 164.12E) since
December 1995, carrying out observations of nitrogen dioxide (NO<sub>2</sub>) and ozone (O<sub>3</sub>). The recent advances in sensor technologies and processor capabilities, suggested the setup of a new equipment, based on the same optical layout of the 'old' GASCOD , with enhanced performances and improved capabilities for the measurements of solar radiation in the
UV-visible spectral range (300-700nm). The efforts accomplished, allowed for the increase of the investigated tracers.
Actually, mainly due to the enlargement of the covered spectral range and to the adoption of a CCD sensor, in addition to
the NO<sub>2</sub> and O<sub>3</sub> compounds, others species can be monitored with the new instrumental setup such as bromine, chlorine and iodine oxides (BrO, OClO and IO). The innovative equipment called GASCODNG (GASCOD New Generation)
was installed at MZS during the 2012/2013 Italian Antarctic expedition, in the framework of the research projects
SAMOA (Automatic Station Monitoring Antarctic Ozonosphere) and MATAGRO (Monitoring Atmospheric Tracers in
Antarctica with Ground Based Observations) funded by the Italian and Portuguese Antarctic programs respectively. In
this paper a brief description of the new equipment is provided, highlighting the main improvements with regard to the
'old' one. Furthermore the full dataset (1996 - 2012) of NO<sub>2</sub> total columns, obtained with the GASCOD installed at MZS,
is compared with the data obtained with satellite borne equipments (GOME, SCIAMACHY, OMI and GOME2) and the
main statistical parameters are analyzed and discussed in detail.
Since the recognition during the seventies of the importance played by the minor atmospheric compounds in the climate
system (gases and aerosols), the studies regarding the chemistry and dynamical processes of Ozone (O<sub>3</sub>) and of nitrogen
dioxide (NO<sub>2</sub>) at high and mid-latitudes, became a fruitful field of research.
This work deals mainly with the retrieval and analysis of O<sub>3</sub> and NO<sub>2</sub> total columns and vertical profiles over the Evora
Observatory (South of Portugal) for the period 2007-2008. The products presented in this paper are obtained from
spectral measurements carried out with the UV-Vis. Spectrometer for Atmospheric Tracers Monitoring - SPATRAM,
installed at the Observatory of the Geophysics Centre of Evora (CGE) since 2004. The application of the Differential
Optical Absorption Spectroscopy (DOAS) algorithms to the spectral zenith-sky measurements is presented and
discussed. The inversion technique applied to the output of the DOAS procedures (the trace gases content along the
optical path of measurements: the slant column densities -SCD- of the analyzed absorber) are examined. The first
observations obtained with the SPATRAM instrument regarding stratospheric bromine oxide (BrO) are shown. In
addition, the comparison of the ground-based measurements with data derived from satellite equipments (OMI and
SCIAMACHY), are discussed.
The multi purpose UV-Vis. Spectrometer for Atmospheric Tracers Measurement (SPATRAM) is installed at the
Observatory of the Geophysics Centre of Evora (38.5º N, 7.9º W) - Portugal, since 2004, measuring the zenith scattered
radiation in the 300-550 nm spectral range. The main products are the total column and the vertical profiles of NO<sub>2</sub> and
O3 obtained with the application of the Differential Optical Absorption Spectroscopy (DOAS) algorithms and with
inversion schemes based on the Optimal Estimation methods respectively. Recently (February 2009), the MIGE
(Multiple Input Geometry Equipment) was coupled to the SPATRAM instrument allowing for the measurements of the
diffused radiation in directions away from the zenith one (Off-Axis). MIGE is an alt-azimuth platform based on a very
simple optical layout, using an optical fibre to transmit the radiation inside the monochromator of the SPATRAM
equipment. Thanks to the solution adopted in the developing phase, MIGE is able to scan the whole hemisphere. In this
work, after a brief description of the MIGE, the first and preliminary results for vertical profiles of NO<sub>2</sub> in the Planetary
Boundary Layer (PBL), and the values of Slant Column Densities (SCD) of O<sub>3</sub> and SO<sub>2</sub> measured in Off-Axis
configuration at Evora Station, are presented and discussed.