Results from the validation campaign of the ozone radiometer GROMOS-C at the NDACC station of La Réunion Island

Fernandez Vidal, Susana; Rüfenacht, Rolf; Kämpfer, Niklaus; Portafaix, Thierry; Posny, Françoise; Payen, Guillaume (2016). Results from the validation campaign of the ozone radiometer GROMOS-C at the NDACC station of La Réunion Island. Atmospheric chemistry and physics Discussions, pp. 1-23. European Geosciences Union 10.5194/acp-2016-117

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Ozone performs a key role in the middle atmosphere and its monitoring is thus necessary.

At the Institute of Applied Physics of the University of Bern, Switzerland, we built a new ground-based microwave radiometer, GROMOS-C (GRound based Ozone MOnitoring System for Campaigns). It has a compact design and can be operated remotely with very little maintenance requirements, being therefore suitable for remote deployments. It has been conceived to measure the vertical distribution of ozone in the middle atmosphere, by observing pressure-broadened emission spectra at a frequency of 110.836 GHz. In addition, meridional and zonal wind profiles can be retrieved, based on the Doppler shift of the ozone line measured in the four directions of observation (north, east, south and west).

In June 2014 the radiometer was installed at the Maïdo observatory, on Réunion island (21.2° S, 55.5° E). High-resolution ozone spectra were recorded continuously over 7 months. Vertical profiles of ozone have been retrieved through an optimal estimation inversion process, using the Atmospheric Radiative Transfer Simulator ARTS2 as the forward model. The validation is performed against ozone profiles from the Microwave Limb Sounder (MLS) on the Aura satellite, the ozone lidar located at the observatory and with ozone profiles from weekly radiosondes. Zonal and meridional winds retrieved from GROMOS-C data are validated against another wind radiometer located in situ, WIRA. In addition, we compare both ozone and winds with ECMWF (European Centre for Medium-Range Weather Forecasts) model data. Results show that GROMOS-C provides reliable ozone profiles between 30 and 0.02 hPa. The comparison with lidar profiles shows a very good agreement at all levels. The accordance with the MLS data set is within 5 % for pressure levels between 25 and 0.2 hPa. GROMOS-C's wind profiles are in good agreement with the observations by WIRA and with the model data, differences are below 5 m s−1 for both.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Institute of Applied Physics
08 Faculty of Science > Institute of Applied Physics > Microwaves

UniBE Contributor:

Fernandez Vidal, Susana, Rüfenacht, Rolf, Kämpfer, Niklaus


600 Technology > 620 Engineering
500 Science
500 Science > 530 Physics




European Geosciences Union




Simone Corry

Date Deposited:

13 Jul 2017 10:49

Last Modified:

05 Dec 2022 15:03

Publisher DOI:





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