A New NDACC- and TCCON-Compliant FTIR Observatory in Bologna (Italy) for Greenhouse Gas and Trace Gas Measurements

High-resolution ground-based Fourier Transform InfraRed (FTIR) spectroscopy is a key technique for monitoring atmospheric composition, in particular, greenhouse gases, providing vertically integrated information essential for climate studies, emission estimates, and satellite data validation. Within the framework of the PNRR EMM and ITINERIS projects, two new ground-based FTIR spectrometers have been installed at the CNR research area in Bologna, Italy, significantly enhancing the national observational capability in these fields.

The first instrument, a Bruker IFS 125HR, operates in the infrared spectral range from approximately 850 to 9000 cm⁻¹, with a spectral resolution of about 0.0036 cm⁻¹, enabling the retrieval of a wide set of atmospheric trace gases and minor atmospheric constituents, including CO₂, CH₄, N₂O, CO, O₃, HNO₃, HCl, HF, C₂H₆, HCN, and HDO. These measurements are crucial for investigating changes in atmospheric composition and their impact on the Earth’s radiative balance, as well as for deriving greenhouse gas emissions and trends.

The second instrument is a Bruker EM27/SUN, which operates in the NIR range from 4000 to 12000 cm⁻¹, thus allowing the retrieval of CO₂, CH₄, CO, and H₂O. Being part of the COCCON network, its data are analyzed on a daily basis, and the resulting GEOMS files are regularly delivered to the network for public distribution.

The FTIR spectrometers are located in the Po Valley, one of the most polluted regions in Europe, offering a unique opportunity to observe greenhouse gases and air pollutants under conditions of strong anthropogenic influence. The IFS 125HR is fully compliant with the NDACC and TCCON network requirements, ensuring standardized data acquisition, calibration, and processing procedures and thereby allowing direct comparison with other ground-based FTIR sites worldwide and with satellite observations. This installation represents the first FTIR facility of its kind in Italy and the central Mediterranean region, providing significant scientific value at both national and international levels.