Atmospheric ammonia (NH₃) over the Paris megacity: 9 years of total column observations from ground-based infrared remote sensing

Benoît Tournadre (1) , Pascale Chelin (1) , Mokhtar Ray (1) , Juan Cuesta (1) , Rebecca D. Kutzner (1) , Xavier Landsheere (1) , Audrey Fortems-Cheiney (1) , Jean-Marie Flaud (1) , Frank Hase (2) , Thomas Blumenstock (2) , Johannes Orphal (2) , Camille Viatte (3) , Claude Camy-Peyret (4)

1 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques
2 IMK - Institute for Meteorology and Climate Research
3 TROPO - LATMOS
4 IPSL (FR_636) - Institut Pierre-Simon-Laplace

In this paper, we present the first multiyear time series of atmospheric ammonia (NH₃) ground-based measurements in the Paris region (Créteil, 48.79° N, 2.44° E, France) retrieved with the midresolution "Observations of the Atmosphere by Solar absorption Infrared Spectroscopy" (OASIS) ground-based Fourier transform infrared solar observatory. Located in an urban region, OASIS has previously been used for monitoring air quality (tropospheric ozone and carbon monoxide) thanks to its specific column sensitivity across the whole troposphere down to the atmospheric boundary layer. A total of 4920 measurements of atmospheric total columns of ammonia have been obtained from 2009 to 2017, with uncertainties ranging from 20 % to 35 %, and have been compared with NH₃ concentrations derived from the Infrared Atmospheric Sounding Interferometer (IASI). OASIS ground-based measurements show significant interannual and seasonal variabilities of atmospheric ammonia. NH₃ total columns over the Paris megacity (12 million people) vary seasonally by 2 orders of magnitude from approximately 0.1×10¹⁶ molec. cm^-2 in winter to 10×10¹⁶ molec. cm^-2 for spring peaks, probably due to springtime spreading of fertilizers on surrounding croplands.

Domaines: Océan, Atmosphère

Benoît Tournadre, Pascale Chelin, Mokhtar Ray, Juan Cuesta, Rebecca D. Kutzner, et al.. Atmospheric ammonia (NH₃) over the Paris megacity: 9 years of total column observations from ground-based infrared remote sensing. Atmospheric Measurement Techniques, 2020, 13, pp.3923-3937. ⟨10.5194/amt-13-3923-2020⟩. ⟨insu-03721898⟩