Persistent sensitivity of Asian aerosol to emissions of nitrogen oxides

Kharol, Shailesh Kumar; Martin, Randall V.; Philip, Sajeev; Vogel, S.; Henze, D. K.; Chen, D.; Wang, Yuxuan; Zhang, Q.; Heald, Colette L.

doi:10.1002/grl.50234

Cited by 46 publications

(44 citation statements)

References 41 publications

(56 reference statements)

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“…Overestimation of NH 3 surface concentrations in GEOS-Chem in China is found in Wang et al (2013) when using NH 3 emis- sions from Streets et al (2003), leading to an overestimation of nitrate aerosol concentrations in China. Observations from the Infrared Atmospheric Sounding Interferometer (IASI) remote sensing instrument have discrepancies over China with NH 3 concentrations in GEOS-Chem (Kharol et al, 2013;Clarisse et al, 2009) that may in part be improved by the impacts of bidirectional exchange. However, observations from TES show NH 3 concentrations in GEOS-Chem (with NH 3 emissions from Streets et al, 2003) are underestimated in many places of the globe including China .…”

Section: Global Modeling Resultsmentioning

confidence: 99%

Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

et al. 2015

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Abstract. Bidirectional air-surface exchange of ammonia (NH 3 ) has been neglected in many air quality models. In this study, we implement the bidirectional exchange of NH 3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH 3 livestock emissions and evaluate the recently developed MASAGE_NH 3 bottom-up inventory. While updated diurnal variability improves comparison of modeled-to-hourly in situ measurements in the southeastern USA, NH 3 concentrations decrease throughout the globe, up to 17 ppb in India and southeastern China, with corresponding decreases in aerosol nitrate by up to 7 µg m −3 . The ammonium (NH + 4 ) soil pool in the bidirectional exchange model largely extends the NH 3 lifetime in the atmosphere. Including bidirectional exchange generally increases NH 3 gross emissions (7.1 %) and surface concentrations (up to 3.9 ppb) throughout the globe in July, except in India and southeastern China. In April and October, it decreases NH 3 gross emissions in the Northern Hemisphere (e.g., 43.6 % in April in China) and increases NH 3 gross emissions in the Southern Hemisphere. Bidirectional exchange does not largely impact NH + 4 wet deposition overall. While bidirectional exchange is fundamentally a better representation of NH 3 emissions from fertilizers, emissions from primary sources are still underestimated and thus significant model biases remain when compared to in situ measurements in the USA. The adjoint of bidirectional exchange has also been developed for the GEOS-Chem model and is used to investigate the sensitivity of NH 3 concentrations with respect to soil pH and fertilizer application rate. This study thus lays the groundwork for future inverse modeling studies to more directly constrain these physical processes rather than tuning bulk unidirectional NH 3 emissions.

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Section: Global Modeling Resultsmentioning

confidence: 99%

Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

et al. 2015

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“…The model adjoint is first described by Henze et al (2007) for aerosols and Kopacz et al (2009) for carbon monoxide. It has been highly validated and applied in studies to analyze aerosol sensitivities and constrain aerosol sources in the United States Zhu et al, 2013;Mao et al, 2015) and China (Kharol et al, 2013;Zhang et al, 2015Zhang et al, , 2016Qu et al, 2017).…”

Section: The Geos-chem Adjointmentioning

confidence: 99%

Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates

et al. 2018

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Abstract. Current estimates of agricultural ammonia (NH 3 ) emissions in China differ by more than a factor of 2, hindering our understanding of their environmental consequences. Here we apply both bottom-up statistical and top-down inversion methods to quantify NH 3 emissions from agriculture in China for the year 2008. We first assimilate satellite observations of NH 3 column concentration from the Tropospheric Emission Spectrometer (TES) using the GEOS-Chem adjoint model to optimize Chinese anthropogenic NH 3 emissions at the 1/2 • × 2/3 • horizontal resolution for MarchOctober 2008. Optimized emissions show a strong summer peak, with emissions about 50 % higher in summer than spring and fall, which is underestimated in current bottom-up NH 3 emission estimates. To reconcile the latter with the topdown results, we revisit the processes of agricultural NH 3 emissions and develop an improved bottom-up inventory of Chinese NH 3 emissions from fertilizer application and livestock waste at the 1/2 • × 2/3 • resolution. Our bottom-up emission inventory includes more detailed information on crop-specific fertilizer application practices and better accounts for meteorological modulation of NH 3 emission factors in China. We find that annual anthropogenic NH 3 emissions are 11.7 Tg for 2008, with 5.05 Tg from fertilizer application and 5.31 Tg from livestock waste. The two sources together account for 88 % of total anthropogenic NH 3 emissions in China. Our bottom-up emission estimates also show a distinct seasonality peaking in summer, consistent with topdown results from the satellite-based inversion. Further evaluations using surface network measurements show that the model driven by our bottom-up emissions reproduces the observed spatial and seasonal variations of NH 3 gas concentrations and ammonium (NH + 4 ) wet deposition fluxes over China well, providing additional credibility to the improvements we have made to our agricultural NH 3 emission inventory.

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“…The GEOS-Chem model has been previously applied to study PM2.5 over India (e.g., Boys et al 2014;Kharol et al 2013;Philip et al 2014a;Li et al 2017) including relating satellite observations of aerosol optical depth to ground-level PM2.5 for the GBD assessment (Brauer et al 2012van Donkelaar et al 2010van Donkelaar et al , 2015van Donkelaar et al , 2016. The simulations undertaken in this work represent one of the finest resolution efforts to date to both represent India, and global scale processes.…”

Section: Model Simulations and Evaluationmentioning

confidence: 99%

Source influence on emission pathways and ambient PM<sub>2.5</sub> pollution over India (2015–2050)

Venkataraman¹,

Bräuer²,

Tibrewal³

et al. 2017

Preprint

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Abstract. India currently experiences degraded air quality, with future economic development leading to challenges for air quality management. Scenarios of sectoral emissions of fine particulate matter and its precursors were developed and evaluated for 2015-2050, under specific pathways of diffusion of cleaner and more energy efficiency technologies. The impacts of individual source-sectors on PM2.5 concentrations were assessed through GEOS-Chem model simulations of spatially and temporally resolved particulate matter concentrations, followed by population-weighted aggregation to national and state 25 levels. PM2.5 pollution is a pan-India problem, with a regional character, not limited to urban areas or megacities. Under present day emissions, levels in most states exceeded the national PM2.5 standard (40 µg/m 3 ). Future evolution of emissions under current regulation or under promulgated or proposed regulation, yield deterioration in future air-quality in 2030 and 2050.Only under a scenario where more ambitious measures are introduced, promoting a total shift away from traditional biomass technologies and a very large shift (80-85%) to non-fossil electricity generation, was an overall reduction in PM2. 2 projected to increase in all future scenarios, largely from decreases in the influence of other PM2.5 sources. Overall, the findings suggest a large regional background of PM2.5 pollution (from residential biomass, agricultural residue burning and power plant and industrial coal), underlying that from local sources (transportation, brick kiln, distributed diesel) in highly polluted areas.

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Persistent sensitivity of Asian aerosol to emissions of nitrogen oxides

Cited by 46 publications

References 41 publications

Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates

Source influence on emission pathways and ambient PM<sub>2.5</sub> pollution over India (2015–2050)

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Persistent sensitivity of Asian aerosol to emissions of nitrogen oxides

Cited by 46 publications

References 41 publications

Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates

Source influence on emission pathways and ambient PM&lt;sub&gt;2.5&lt;/sub&gt; pollution over India (2015–2050)

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Source influence on emission pathways and ambient PM<sub>2.5</sub> pollution over India (2015–2050)