Ground-based Observations

The experience of BIRA-IASB in atmospheric research activities using ground-based UV-Visible DOAS spectrometers goes back to the early nineties. The aim of the research is the long-term monitoring of the minor components involved in the catalytic destruction of the ozone layer and the study of anthropogenic pollution.

BIRA-IASB operates several UV-Visible instruments, both during specific campaigns and continuously at different stations

Location of the BIRA-IASB UV-Vis instruments (red dots are the station, while black dots are the campaigns)

BIRA-IASB stations

BIRA-IASB measures at the following stations:

• Harestua, Jungfraujoch, and OHP, in the framework of the NDACC network (Network for the Detection of Atmospheric Composition Change)
• Uccle and Beijing in the context of specific projects (the AGACC and the AMFIC project, repsectively)

In the perspective of the installation of a new NDACC station on Reunion Island, BIRA-IASB has operated a MAX-DOAS instrument at Saint Denis (21°S), in 2004-2005.

BIRA-IASB campaigns

Recently, BIRA-IASB also participated to the following international field campaigns:

• CINDI tropospheric NO₂ campaigns in Cabauw (The Netherlands), June-July 2009
• SAUNA ozone intercomparison campaigns in Sodankylä (Finland), March/May 2006 and February/April 2007
• DANDELIONS tropospheric NO₂ campaigns in Cabauw (The Netherlands), May/July 2005 and September 2006
• FORMAT UE formaldehyde campaigns, in Milano region (Italy), July 2002 and Sept/Oct 2003
• NDACC high latitude UV/VIS intercomparison campaign, in Andoya (Norway), Feb/March 2003

These UV-Vis instruments are based on Differential Optical Absorption Spectroscopy (DOAS, Platt 1994). The evolution of the traditional passive zenith sky technique (allowing the monitoring of stratospheric components, such as the O3 and NO2 and minor trace species like BrO and OClO)and the development of Multi-Axis instruments (MAXDOAS), allows the measurement of tropospheric pollutants and ozone precursors, like NO2, HCHO, O4, IO, CHOCHO and SO2.

This newly developed remote sensing technique has a largest sensitivity towards the boundary layer and is ideally suited for the study of a layer close to the ground and thus for studies related to air quality issues. BIRA-IASB recently developed a "new generation" of MAXDOAS instruments, described here.

NDACC recommendations for total O₃ column retrieval in the visible Chappuis bands

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Cross sections :

O₃ AMF look-up tables :

O₃ column averaging kernel look-up tables :

NDACC recommendations for stratospheric NO₂ UV-vis measurements

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NO₂ AMF look-up tables :