Wet nitrogen (N) deposition to urban Latin America: Filling in the gaps with GEOS-Chem. (1st June 2022)

• Record Type: Journal Article
• Authors: Ponette-González, Alexandra G.; Lewis, Haley; Henderson, Barron H.; Carnelos, Danilo; Piñeiro, Gervasio; Weathers, Kathleen C.; Schwede, Donna B.
• Is Part Of: Atmospheric environment. Volume 278(2022)
• Publication Date: 2022-06-01
• Subjects: Air pollution -- Chemical transport models -- Cities -- Critical loads -- Livestock -- Rainwater chemistry; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2022.119095
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: In Latin America, atmospheric deposition is a major vector of nitrogen (N) input to urban systems. Yet, measurements of N deposition are sparse, precluding analysis of spatial patterns, temporal trends, and ecosystem impacts. Chemical transport models can be used to fill these gaps in the absence of dense measurements. Here, we evaluate the performance of a global 3-D chemical transport model in simulating spatial and interannual variation in wet inorganic N (NH4 –N + NO3 –N) deposition across urban areas in Latin America. Monthly wet and dry inorganic N deposition to Latin America were simulated for the period 2006–2010 using the GEOS-Chem Chemical Transport Model. Published estimates of observed wet or bulk inorganic N deposition measured between 2006 and 2010 were compiled for 16 urban areas and then compared with model output from GEOS-Chem. Observed mean annual inorganic N deposition to the urban study sites ranged from 5.7 to 14.2 kg ha −1 yr −1, with NH4 –N comprising 48–90% of the total. Results show that simulated N deposition was highly correlated with observed N deposition across sites (R 2 = 0.83, NMB = −50%). However, GEOS-Chem generally underestimated N deposition to urban areas in Latin America compared to observations. Underestimation due to bulk sampler dry deposition artifacts was considered and improved bias without improving correlation. In contrast to spatial variation, the model did not capture year-to-year variation well. Discrepancies between modeled and observed values exist, in part, because of uncertainties in Latin American N emissions inventories. Our findings indicate that even at coarse spatial resolution, GEOS-Chem can be used to simulate N deposition to urban Latin America, improving understanding of regional deposition patterns and potential ecological effects. Highlights: GEOS-Chem simulated wet inorganic N deposition is evaluated for urban Latin America. Across urban areas, GEOS-Chem captures spatial variability in N deposition well. At the site level, the model does not capture year-to-year variation. Observed inorganic N deposition to 16 urban areas ranged 5.7–14.2 kg ha −1 yr −1 .