A074-03
NH3 emission trends from 2013 to 2018 over Europe constrained using CrIS remote sensing measurements of NH3

Wednesday, 9 December 2020: 10:36
Virtual
Hansen Cao1, Daven K Henze1, Mark Shephard2, Enrico Dammers3, Karen Cady-Pereira4, Matthew Alvarado5, Chantelle Rose Lonsdale6, Liye Zhu7 and Kazuyuki Miyazaki8, (1)University of Colorado Boulder, Boulder, CO, United States, (2)Environment and Climate Change Canada, Toronto, Canada, (3)TNO, Utrecht, Netherlands, (4)Atmospheric and Environmental Research, Lexington, MA, United States, (5)AER, Lexington, United States, (6)AER, Inc., Lexington, MA, United States, (7)Colorado State University, Fort Collins, CO, United States, (8)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
Abstract:
Ammonia (NH3) is an important precursor of fine particulate matter (PM2.5) via formation of ammonium sulfate and ammonium nitrate. Excess deposition of ammonia/ammonium in water leads to eutrophication and thus reduces the ecosystem biodiversity. Satellite remote sensing instruments of atmospheric NH3 have been used to infer its emissions using inversion techniques, which can help examine the efficiency of air pollution control policies. Tracking changes in NOx and SO2 emissions provide additional constraints on NH3 emission estimates through modulation of the atmospheric lifetime of NH3, which were found to be important in particular in East Asia and the US. Early air pollution control policies implemented in European countries since 1991 have achieved a 25% reduction in NH3 emissions from 1990 to 2010, primarily due to decreases in livestock emissions. Still, more than 93% of NH3 emissions over Europe in 2013 are contributed by agricultural sources (EEA, 2017). A recent Gothenburg Protocol has set a decreasing emission ceiling for European countries for the years 2005 to 2020, which aims to reduce NH3 emissions to 3.624 Tg y-1by 2020; however, bottom-up emission estimates still show a slight increase (0.6% y-1) from 2010 to 2018 (EEA, 2020). Here we combine 4D-Var and mass balance approaches to constrain NH3 emissions from 2013 to 2018 over Europe using NH3 measurements from the Cross-track Infrared Sounder (CrIS). We use satellite-derived NOx and SO2 emission reductions in recent years to account for changes in their concentrations impacting atmospheric NH3. We evaluate our top-down emission trend using independent surface measurements of NHx wet deposition and gas-phase NH3 concentrations. This study shows the value of CrIS NH3 in constraining NH3 emission trends and in examining the efficiency of air pollution control policies to facilitate future air pollution management policy making.
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