GenChem v1.0 – a chemical pre-processing and testing system  for atmospheric modelling

Simpson, David; Bergström, R. W.; Briolat, Alain; Imhof, Hannah; Johansson, John; Priestley, Michael; Valdebenito, Álvaro

doi:10.5194/gmd-13-6447-2020

Cited by 20 publications

(25 citation statements)

References 52 publications

(72 reference statements)

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“…A detailed technical description of EMEP MSC-W rv4.0 is documented in Simpson et al (2012). An overview of model updates from version rv4.0 to rv4.34 is presented in Simpson et al (2020). The model has horizontal resolution of 1 • × 1 • and contains 21 terrain-following vertical layers from the surface to 100 hPa.…”

Section: Model Descriptionmentioning

confidence: 99%

A new assessment of global and regional budgets, fluxes, and lifetimes of atmospheric reactive N and S gases and aerosols

Vieno

Stevenson

et al. 2022

Atmos. Chem. Phys.

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Abstract. We used the EMEP MSC-W (European Monitoring and Evaluation Programme Meteorological Synthesizing Centre – West) model version 4.34 coupled with WRF (Weather Research and Forecasting) model version 4.2.2 meteorology to undertake a present-day (2015) global and regional quantification of the concentrations, deposition, budgets, and lifetimes of atmospheric reactive N (Nr) and S (Sr) species. These are quantities that cannot be derived from measurements alone. In areas with high levels of reduced Nr (RDN = NH3+ NH4+), oxidized Nr (OXN = NOx+ HNO3+ HONO + N2O5 + NO3-+ “Other OXN” species), and oxidized Sr (OXS = SO2+ SO42-), RDN is predominantly in the form of NH3 (NH4+ typically <20 %), OXN has majority gaseous species composition, and OXS predominantly comprises SO42- except near major SO2 sources. Most continental regions are now “ammonia rich”, more so than previously, which indicates that, although reducing NH3 emissions will decrease the RDN concentration, decreasing these emissions will have little effect on mitigating secondary inorganic aerosol (SIA). South Asia is the most ammonia-rich region. Coastal areas around East Asia, northern Europe, and the north-eastern United States are “nitrate rich” where NH4NO3 formation is limited by NH3. These locations experience transport of OXN from the adjacent continent and/or direct shipping emissions of NOx, but NH3 concentrations are lower. The least populated continental areas and most marine areas are “sulfate rich”. Deposition of OXN (57.9 TgN yr−1, 51 %) and RDN (55.5 TgN yr−1, 49 %) contribute almost equally to total nitrogen deposition. OXS deposition is 50.5 TgS yr−1. Globally, wet and dry deposition contribute similarly to RDN deposition; for OXN and OXS, wet deposition contributes slightly more. Dry deposition of NH3 is the largest contributor to RDN deposition in most regions except for the Rest of Asia area and marine sectors where NH3 emissions are small and RDN deposition is mainly determined by the transport and rainout of NH4+ (rather than rainout of gaseous NH3). Thus, reductions in NH3 would efficiently reduce the deposition of RDN in most continental regions. The two largest contributors to OXN deposition in all regions are HNO3 and coarse NO3- (via both wet and dry deposition). The deposition of fine NO3- is only important over East Asia. The tropospheric burden of RDN is 0.75 TgN, of which NH3 and NH4+ comprise 32 % (0.24 TgN; lifetime of 1.6 d) and 68 % (0.51 TgN; lifetime of 8.9 d) respectively. The lifetime of RDN (4.9–5.2 d) is shorter than that of OXN (7.6–7.7 d), which is consistent with a total OXN burden (1.20 TgN) almost double that of RDN. The tropospheric burden of OXS is 0.78 TgS with a lifetime of 5.6–5.9 d. Total nitrate burden is 0.58 TgN with fine NO3- only constituting 10 % of this total, although fine NO3- dominates in eastern China, Europe, and eastern North America. It is important to account for contributions of coarse nitrate to global nitrate budgets. Lifetimes of RDN, OXN, and OXS species vary by a factor of 4 across different continental regions. In East Asia, lifetimes for RDN (2.9–3.0 d), OXN (3.9–4.5 d), and OXS (3.4–3.7 d) are short, whereas lifetimes in the Rest of Asia and Africa regions are about twice as long. South Asia is the largest net exporter of RDN (2.21 TgN yr−1, 29 % of its annual emission), followed by the Euro_Medi region. Despite having the largest RDN emissions and deposition, East Asia has only small net export and is therefore largely responsible for its own RDN pollution. Africa is the largest net exporter of OXN (1.92 TgN yr−1, 22 %), followed by Euro_Medi (1.61 TgN yr−1, 26 %). Considerable marine anthropogenic Nr and Sr pollution is revealed by the large net import of RDN, OXN, and OXS to these areas. Our work demonstrates the substantial regional variation in Nr and Sr budgets and the need for modelling to simulate the chemical and meteorological linkages underpinning atmospheric responses to precursor emissions.

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Section: Model Descriptionmentioning

confidence: 99%

A new assessment of global and regional budgets, fluxes, and lifetimes of atmospheric reactive N and S gases and aerosols

Vieno

Stevenson

et al. 2022

Atmos. Chem. Phys.

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“…In this study, we utilize the most recent EMEP MSC-W model version rv4.34. Simpson et al (2020) provide an overview of the changes made to the model since the version rv4.0 documented in Simpson et al (2012). These changes include improved calculations of aerosol surface area and gas aerosol uptake (Stadtler et al, 2018); additional land cover classes and improved leaf area calculations for global biogenic volatile organic compound (BVOC) emission calculation ; a new radiation scheme (Weiss and Norman, 1985) for BVOC and deposition calculations; new chemical mechanisms ; and changes related to sea salt, dust, and other emissions handling.…”

Section: Model Description and Set-upmentioning

confidence: 99%

“…Forest and vegetation fire emissions and international shipping emissions are also included in both inventories. Emissions of dimethyl sulfide (DMS), lightning NO x , soil NO x and isoprene are set as reported in Simpson et al (2017Simpson et al ( , 2020, as are the wind-derived emissions of dust and sea salt (Simpson et al, 2012;Tsyro et al, 2011).…”

Section: Model Description and Set-upmentioning

confidence: 99%

Evaluation of global EMEP MSC-W (rv4.34) WRF (v3.9.1.1) model surface concentrations and wet deposition of reactive N and S with measurements

Heal

Stevenson

et al. 2021

Geosci. Model Dev.

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Abstract. Atmospheric pollution has many profound effects on human health, ecosystems, and the climate. Of concern are high concentrations and deposition of reactive nitrogen (Nr) species, especially of reduced N (gaseous NH3, particulate NH4+). Atmospheric chemistry and transport models (ACTMs) are crucial to understanding sources and impacts of Nr chemistry and its potential mitigation. Here we undertake the first evaluation of the global version of the EMEP MSC-W ACTM driven by WRF meteorology (1∘×1∘ resolution), with a focus on surface concentrations and wet deposition of N and S species relevant to investigation of atmospheric Nr and secondary inorganic aerosol (SIA). The model–measurement comparison is conducted both spatially and temporally, covering 10 monitoring networks worldwide. Model simulations for 2010 compared use of both HTAP and ECLIPSEE (ECLIPSE annual total with EDGAR monthly profile) emissions inventories; those for 2015 used ECLIPSEE only. Simulations of primary pollutants are somewhat sensitive to the choice of inventory in places where regional differences in primary emissions between the two inventories are apparent (e.g. China) but are much less sensitive for secondary components. For example, the difference in modelled global annual mean surface NH3 concentration using the two 2010 inventories is 18 % (HTAP: 0.26 µg m−3; ECLIPSEE: 0.31 µg m−3) but is only 3.5 % for NH4+ (HTAP: 0.316 µg m−3; ECLIPSEE: 0.305 µg m−3). Comparisons of 2010 and 2015 surface concentrations between the model and measurements demonstrate that the model captures the overall spatial and seasonal variations well for the major inorganic pollutants NH3, NO2, SO2, HNO3, NH4+, NO3-, and SO42- and their wet deposition in East Asia, Southeast Asia, Europe, and North America. The model shows better correlations with annual average measurements for networks in Southeast Asia (mean R for seven species: R7‾=0.73), Europe (R7‾=0.67), and North America (R7‾=0.63) than in East Asia (R5‾=0.35) (data for 2015), which suggests potential issues with the measurements in the latter network. Temporally, both model and measurements agree on higher NH3 concentrations in spring and summer and lower concentrations in winter. The model slightly underestimates annual total precipitation measurements (by 13 %–45 %) but agrees well with the spatial variations in precipitation in all four world regions (0.65–0.94 R range). High correlations between measured and modelled NH4+ precipitation concentrations are also observed in all regions except East Asia. For annual total wet deposition of reduced N, the greatest consistency is in North America (0.75–0.82 R range), followed by Southeast Asia (R=0.68) and Europe (R=0.61). Model–measurement bias varies between species in different networks; for example, bias for NH4+ and NO3- is largest in Europe and North America and smallest in East Asia and Southeast Asia. The greater uniformity in spatial correlations than in biases suggests that the major driver of model–measurement discrepancies (aside from differing spatial representativeness and uncertainties and biases in measurements) are shortcomings in absolute emissions rather than in modelling the atmospheric processes. The comprehensive evaluations presented in this study support the application of this model framework for global analysis of current and potential future budgets and deposition of Nr and SIA.

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“…Here it is run with 20 vertical layers and a horizontal resolution of 0.1 × 0.1 degrees driven by ECMWF IFS meteorology (https://www.ecmwf.int/en/research/ modelling-and-prediction). It includes about 170 reactions between approximately 130 gas-and particulate-phase species and tracers (EmChem16 scheme, see Simpson et al, 2017;Simpson et al, 2020), and uses the EQSAM module (Metzger et al, 2002) to describe equilibria between the inorganic aerosols. To calculate dry deposition, the model includes a stomatal conductance algorithm, applied to all pollutants where stomatal control is important (e.g.…”

Section: Emep Msc-w Modelmentioning

confidence: 99%

Good Agreement Between Modeled and Measured Sulfur and Nitrogen Deposition in Europe, in Spite of Marked Differences in Some Sites

Marchetto

Simpson

Aas

et al. 2021

Front. Environ. Sci.

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Atmospheric nitrogen and sulfur deposition is an important effect of atmospheric pollution and may affect forest ecosystems positively, for example enhancing tree growth, or negatively, for example causing acidification, eutrophication, cation depletion in soil or nutritional imbalances in trees. To assess and design measures to reduce the negative impacts of deposition, a good estimate of the deposition amount is needed, either by direct measurement or by modeling. In order to evaluate the precision of both approaches and to identify possible improvements, we compared the deposition estimates obtained using an Eulerian model with the measurements performed by two large independent networks covering most of Europe. The results are in good agreement (bias <25%) for sulfate and nitrate open field deposition, while larger differences are more evident for ammonium deposition, likely due to the greater influence of local ammonia sources. Modeled sulfur total deposition compares well with throughfall deposition measured in forest plots, while the estimate of nitrogen deposition is affected by the tree canopy. The geographical distribution of pollutant deposition and of outlier sites where model and measurements show larger differences are discussed.

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GenChem v1.0 – a chemical pre-processing and testing system for atmospheric modelling

Cited by 20 publications

References 52 publications

A new assessment of global and regional budgets, fluxes, and lifetimes of atmospheric reactive N and S gases and aerosols

A new assessment of global and regional budgets, fluxes, and lifetimes of atmospheric reactive N and S gases and aerosols

Evaluation of global EMEP MSC-W (rv4.34) WRF (v3.9.1.1) model surface concentrations and wet deposition of reactive N and S with measurements

Good Agreement Between Modeled and Measured Sulfur and Nitrogen Deposition in Europe, in Spite of Marked Differences in Some Sites

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