Evaluating 4 years of atmospheric ammonia (NH₃) over Europe using IASI satellite observations and LOTOS-EUROS model results

M. van Damme (1, 2) , R. J. Wichink Kruit (3) , M. Schaap (3) , L. Clarisse (1) , Cathy Clerbaux (4, 1) , Pierre-François Coheur (1) , E. Dammers (2, 3) , A. J. Dolman (2) , J. W. Erisman (2, 5)

1 Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique
2 FALW - Faculty of Earth and Life Sciences [Amsterdam]
3 TNO Climate, Air and Sustainability [Utrecht]
4 TROPO - LATMOS
5 LBI - Louis Bolk Institute

Monitoring ammonia (NH₃) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH₃ distributions generally relies on model calculations. Novel remotely sensed NH₃ burdens provide valuable insights to complement traditional assessments. This paper presents a first quantitative comparison between IASI satellite observations and LOTOS-EUROS model results over Europe and Western Russia. A methodology to account for the variable retrieval sensitivity of the measurements is described. Four years of data (2008-2011) highlight three main agricultural hotspot areas in Europe: the Po Valley, the continental part of Northwestern Europe and the Ebro Valley. The spatial comparison reveals a good overall agreement of the NH₃ distributions in these source regions but also over remote areas and over sea when transport is observed. On average, the measured columns exceed the modeled ones, except for a few cases. Large discrepancies over several industrial areas in Eastern Europe and Russia point to underestimated emissions in the underlying inventories. The temporal analysis over the three hotspot areas reveals that the seasonality is well captured by the model when the lower sensitivity of the satellite measurements in the colder months is taken into account. Comparison of the daily time series indicates possible misrepresentations of the timing and magnitude of the emissions. Finally, specific attention to biomass burning events shows that modeled plumes are less spread out than the observed ones. This is confirmed for the 2010 Russian fires with a comparison using in-situ observations.

Mots clés: regional modeling; satellite/model comparison; ammonia; NH₃; satellite remote sensing; LOTOS-EUROS; IASI

Domaines: Sciences de l'environnement

M. van Damme, R. J. Wichink Kruit, M. Schaap, L. Clarisse, Cathy Clerbaux, et al.. Evaluating 4 years of atmospheric ammonia (NH₃) over Europe using IASI satellite observations and LOTOS-EUROS model results. Journal of Geophysical Research: Atmospheres, 2014, 119 (15), pp.9549-9566. ⟨10.1002/2014JD021911⟩. ⟨hal-01023411⟩