• Citer

Estimating global ammonia (NH 3 ) emissions based on IASI observations from 2008 to 2018

par Luo, Zhenqi;Zhang, Yuzhong;Chen, Wei;Van Damme, Martin ;Coheur, Pierre ;Clarisse, Lieven
Référence Atmospheric chemistry and physics, 22, 15, page (10375-10388)
Publication Publié, 2022-08

Article révisé par les pairs

• Accès en ligne
• Détails
• Contenu
• Statistiques

Résumé :

Abstract. Emissions of ammonia (NH3) to the atmosphere impact humanhealth, climate, and ecosystems via their critical contributions tosecondary aerosol formation. However, the estimation of NH3 emissions is associatedwith large uncertainties because of inadequate knowledge about agriculturalsources. Here, we use satellite observations from the Infrared AtmosphericSounding Interferometer (IASI) and simulations from the GEOS-Chem model toconstrain global NH3 emissions over the period from 2008 to 2018. We updatethe prior NH3 emission fluxes with the ratio between biases insimulated NH3 concentrations and effective NH3 lifetimes againstthe loss of the NHx family. In contrast to the approximate factor of 2discrepancies between top-down and bottom-up emissions found in previousstudies, our method results in a global land NH3 emission of 78 (70–92) Tg a−1, which is ∼30 % higher than the bottom-up estimates.Regionally, we find that the bottom-up inventory underestimates NH3emissions over South America and tropical Africa by 60 %–70 %, indicatingunderrepresentation of agricultural sources in these regions. We find agood agreement within 10 % between bottom-up and top-down estimates overthe US, Europe, and eastern China. Our results also show significantincreases in NH3 emissions over India (13 % per decade), tropicalAfrica (33 % per decade), and South America (18 % per decade)during our study period, which is consistent with the intensifying agriculturalactivity in these regions in the past decade. We find that the inclusion of thesulfur dioxide (SO2) column observed by satellite is crucial for moreaccurate inference of NH3 emission trends over important source regionssuch as India and China where SO2 emissions have changed rapidly inrecent years.