Boundary-layer Air Quality-analysis Using Network of Instruments (BAQUNIN) Super-Site includes ground based active and passive remote sensing instruments operating in synergy, offering quantitative and qualitative information for a wide range of atmospheric parameters for atmospheric chemistry (satellite) validation activities and Planetary Boundary Layer (PBL) studies. The instruments are located in three different sites: an urban component (Physics Department of Sapienza University Sapienza, Rome), a semi-rural component (CNR-ISAC, Tor Vergata) and a rural component (CNR-IIA, Montelibretti), each hosting at least one BAQUNIN Pandora instrument and,  as the case of Sapienza, a large number of other atmospheric remote sensing devices.

As can be depicted from Figure, the Sapienza site is located in an Urban Environment resulting of particular relevance for atmospheric pollution monitoring and characterisation. In addition, the city of Rome is located not far from the Tyrrhenian coasts and exposed to sea-breeze circulation and to extreme aerosol events, as Saharan dust is frequently transported through the Mediterranean Sea. Rome is also subject to energetic meteorological events, especially during autumn and winter periods. This configuration is unique in Europe: not considering the very favourable position and the variety of atmospheric situations that can be encountered, it combines state-of-art instrument operated by highly qualified researchers. A further point of uniqueness is the fact that BAQUNIN is a cross-point of the following international networks: AERONET, EUROSKYRAD, EUBREWNET and PGN. This implies that, within BAQUNIN, QA and Best Practice procedures and protocols are applied.

The driver for the BAQUNIN project is the validation of satellite atmospheric products, ranging from aerosol and cloud to trace gases concentrations. This is achieved through the coordination of a team composed by SERCO, University Sapienza, CNR-ISAC and CNR-IIA researchers and remote sensing specialists. The BAQUNIN team members’ responsibilities range from simple daily instrumental maintenance tasks to the liaising with satellite Cal/Val teams for the definition of validation protocols.   The second objective of BAQUNIN is to contribute to scientific developments in urban boundary layer studies, exploiting the information content of all data acquired during the project lifetime.