Global atmospheric inversion of the anthropogenic NH ₃ emissions over 2019–2022 using the LMDZ-INCA chemistry transport model and the IASI NH ₃ observations

Abstract. Ammonia (NH3) emissions have been on a continuous rise due to extensive fertilizer usage in agriculture and increasing production of manure and livestock. However, the current global-to-national NH3 emission inventories exhibit large uncertainties. We provide atmospheric inversion estimates of the global NH3 emissions over 2019–2022 at 1.27° × 2.5° horizontal and daily (at 10 d scale) resolution. We use IASI-ANNI-NH3-v4 satellite observations, simulations of NH3 concentrations with the chemistry transport model LMDZ-INCA, and the finite difference mass-balance approach for inversions of global NH3 emissions. We take advantage of the averaging kernels provided in the IASI-ANNI-NH3-v4 dataset by applying them consistently to the LMDZ-INCA NH3 simulations for comparison to the observations and then to invert emissions. The average global anthropogenic NH3 emissions over 2019–2022 are estimated as ∼97 (94–100) Tg yr−1, which is ∼61 % (∼55 %–65 %) higher than the prior Community Emissions Data System (CEDS) inventory's anthropogenic NH3 emissions and significantly higher than two other global inventories: CAMS's anthropogenic NH3 emissions (by a factor of ∼1.8) and the Calculation of AMmonia Emissions in ORCHIDEE (CAMEO) agricultural and natural soil NH3 emissions (by ∼1.4 times). The global and regional budgets are mostly within the range of other inversion estimates. The analysis provides confidence in their seasonal variability and continental- to regional-scale budgets. Our analysis shows a rise in NH3 emissions by ∼5 % to ∼37 % during the COVID-19 lockdowns in 2020 over different regions compared to the same-period emissions in 2019. However, this rise is probably due to a decrease in atmospheric NH3 sinks due to the decline in NOx and SO2 emissions during the lockdowns.