DANDELIONS campaigns

The DANDELIONS (Dutch Aerosol and Nitrogen Dioxide Experiments for vaLIdation of OMI and SCIAMACHY) project encompasses validation of OMI, SCIAMACHY of nitrogen dioxide (NO2) over the Netherlands.

Description of the campaigns

Two measurement campaigns took place in Cabauw (52° N, 5° E, The Netherlands), one from May to July 2005, and the second in September 2006, gathering in a synergistic way several type of ground-based measurement techniques (http://www.knmi.nl/omi/research/validation/dandelions).

Overview and first results are presented in Brinksma et al., 2008, while the entire dataset is accessible on the AVDC (Aura Validation Data Center) website.

BIRA-IASB instruments

BIRA-IASB participated with a MAXDOAS instrument in 2005 and with 2 MAXDOAS (one at ground and one at 200m height) and a newly developed DirectSun instrument in 2006, with main focuses on intercomparison of MAXDOAS technique (2 other MAXDOAS measuring simultaneously, operated by the university of Bremen and the university of Heidelberg), satellite validation and study of vertical and horizontal inhomogeneities in the tropospheric NO2 field, with particular interest in the Boundary Layer (BL).

BIRA-IASB operated several instruments in 2005: MAXDOAS UV/VIS (308-455 nm) MiniDOAS (290-435 nm) BIRA-IASB operated several instruments in 2006: MAXDOAS MAXDOAS UV/VIS (322-467 nm) Direct-Sun (335-450 nm) MiniDOAS (290-435 nm) with main focus on: total and tropospheric NO2, HCHO, O4, CHOCHO.

Scientific highligths

An example of temporal variation of the NO2 in showed in figure 1, while the impact of the horizontal inhomogeneities can be seen in figure 2 where the different MAXDOAS are compared one to the other, including the Heidelberg instrument that is simultaneously measuring in 3 azimutal directions.

These inhomogeneities have a large impact in the context satellite validation, where the local columns retrieval from the ground-based instruments are compared to NO2 columns values averaged within an horizontal extended pixel of several tens of km² at best (OMI pixel: 13x24km², SCIAMACHY pixel: 60x30km²). Detailed information can be found in Brinksma et al. (2008) and in Celarier et al. (2008) for the OMI validation, and in Pinardi et al. (in preparation) including SCIAMACHY.

List of publications

Brinksma, E., G. Pinardi, R. Braak, H. Volten, A. Richter, A. Schönhardt, M. Van Roozendael, C. Fayt, C. Hermans, R. Dirksen, T. Vlemmix, A.J.C Berkhout, D.P.J. Swart, H. Oetjen, F. Wittrock, T. Wagner, O. W. Ibrahim, G. de Leeuw, M. Moerman, L. Curier, E. A. Celarier, W. H. Knap, J. P. Veefkind, H.J. Eskes, M. Allaart, R. Rothe, A. J. M Piters, and P. Levelt (2008), The 2005 and 2006 DANDELIONS NO2 and Aerosol Intercomparison Campaigns, J. Geophys. Res., 113, D16S46, http://dx.doi.org/10.1029/2007JD008808

Celarier, E. A., E. J. Brinksma, J. F. Gleason, J. P. Veefkind, A. Cede, J. R. Herman, D. Ionov, F. Goutail, J.-P. Pommereau, J.-C. Lambert, M. van Roozendael, G. Pinardi, F. Wittrock, A. Schönhardt, A. Richter, O. W. Ibrahim, T. Wagner, B. Bojkov, G. Mount, E. Spinei, C. M. Chen, T. J. Pongetti, S. P. Sander, E. J. Bucsela, M. O. Wenig, D. P. J. Swart, H. Volten, M. Kroon, and P. F. Levelt (2008), Validation of Ozone Monitoring Instrument nitrogen dioxide columns, J. Geophys. Res., 113, D15S15, http://dx.doi.org/10.1029/2007JD008908

Hains, J., F. Boersma, M. Kroon, R. Dirksen, R. C. Cohen, A. Perring, E. Bucsela, H. Volten, D. Swart, A. Richter, F. Wittrock, A. Schoenhardt, T. Wagner, O. Ibrahim, M. Van Roozendael, G. Pinardi, J. F. Gleason, J. Veefkind, and P. Levelt (2010), Testing and improving OMI DOMINO tropospheric NO2 using observations from the DANDELIONS and INTEX-B validation campaigns, J. Geophys. Res., 115, D05301, doi:10.1029/2009JD012399.