scholarly journals Ozone air quality simulations with WRF-Chem (v3.5.1) over Europe: Model evaluation and chemical mechanism comparison

2016 ◽  
Author(s):  
Kathleen A. Mar ◽  
Narendra Ojha ◽  
Andrea Pozzer ◽  
Tim M. Butler
Keyword(s):  
Gas Phase ◽  
Surface Ozone ◽  
Strong Dependence ◽  
Model Performance ◽  
Ground Level ◽  
Chemical Mechanism ◽  
Chemical Mechanisms ◽  
Reaction Rate Constants ◽  
Health Related ◽  
Phase Chemistry

Abstract. We present an evaluation of the online regional model WRF-Chem over Europe with a focus on ground-level ozone (O3) and nitrogen oxides (NOx). The model performance is evaluated for two chemical mechanisms, MOZART-4 and RADM2, for year-long simulations. Model-predicted surface meteorological variables (e.g., temperature, wind speed and direction) compared well overall with surface-based observations, consistent with other WRF studies. WRF-Chem simulations employing MOZART-4 as well as RADM2 chemistry were found to reproduce the observed spatial variability in surface ozone over Europe. However, the absolute O3 concentrations predicted by the two chemical mechanisms were found to be quite different, with MOZART-4 predicting O3 concentrations up to 20 μg m−3 greater than RADM2 in summer. Compared to observations, MOZART-4 chemistry overpredicted O3 concentrations for most of Europe in the summer and fall, with a summertime domain-wide mean bias of +10 μg m−3 against observations from the AirBase network. In contrast, RADM2 chemistry generally led to an underestimation of O3 over the European domain in all seasons. We found that the use of the MOZART-4 mechanism, evaluated here for the first time for a European domain, led to lower absolute biases than RADM2 when compared to ground-based observations. The two mechanisms show relatively similar behavior for NOx, with both MOZART-4 and RADM2 resulting in a slight underestimation of NOx compared to surface observations. Further investigation into the differences between the two mechanisms revealed that the net midday photochemical production rate of O3 in summer is higher for MOZART-4 than for RADM2 for most of the domain. The largest differences in O3 production can be seen over Germany, where net O3 production in MOZART-4 is seen to be higher than in RADM2 by 1.8 ppb hr−1 (3.6 μg m−3 hr−1) or more. We also show that, while the two mechanisms exhibit similar NOx-sensitivity, RADM2 is approximately twice as sensitive to increases in anthropogenic VOC emissions as MOZART-4. Additionally, we found that differences in reaction rate constants for inorganic gas phase chemistry in MOZART-4 vs. RADM2 accounted for a difference of 8 μg m−3 in O3 predicted by the two mechanisms, whereas differences in deposition and photolysis schemes explained smaller differences in in O3. Our results highlight the strong dependence of modeled surface O3 over Europe on the choice of gas phase chemical mechanism, which we discuss in the context of overall uncertainties in prediction of ground-level O3 and its associated health impacts (via the health-related metrics MDA8 and SOMO35).

scholarly journals Ozone air quality simulations with WRF-Chem (v3.5.1) over Europe: model evaluation and chemical mechanism comparison

2016 ◽  
Vol 9 (10) ◽  
pp. 3699-3728 ◽  
Author(s):  
Kathleen A. Mar ◽  
Narendra Ojha ◽  
Andrea Pozzer ◽  
Tim M. Butler
Keyword(s):  
Gas Phase ◽  
Surface Ozone ◽  
Strong Dependence ◽  
Model Performance ◽  
Ground Level ◽  
Chemical Mechanism ◽  
Rate Coefficients ◽  
Chemical Mechanisms ◽  
Health Related ◽  
Phase Chemistry

Abstract. We present an evaluation of the online regional model WRF-Chem over Europe with a focus on ground-level ozone (O3) and nitrogen oxides (NOx). The model performance is evaluated for two chemical mechanisms, MOZART-4 and RADM2, for year-long simulations. Model-predicted surface meteorological variables (e.g., temperature, wind speed and direction) compared well overall with surface-based observations, consistent with other WRF studies. WRF-Chem simulations employing MOZART-4 as well as RADM2 chemistry were found to reproduce the observed spatial variability in surface ozone over Europe. However, the absolute O3 concentrations predicted by the two chemical mechanisms were found to be quite different, with MOZART-4 predicting O3 concentrations up to 20 µg m−3 greater than RADM2 in summer. Compared to observations, MOZART-4 chemistry overpredicted O3 concentrations for most of Europe in the summer and fall, with a summertime domain-wide mean bias of +10 µg m−3 against observations from the AirBase network. In contrast, RADM2 chemistry generally led to an underestimation of O3 over the European domain in all seasons. We found that the use of the MOZART-4 mechanism, evaluated here for the first time for a European domain, led to lower absolute biases than RADM2 when compared to ground-based observations. The two mechanisms show relatively similar behavior for NOx, with both MOZART-4 and RADM2 resulting in a slight underestimation of NOx compared to surface observations. Further investigation of the differences between the two mechanisms revealed that the net midday photochemical production rate of O3 in summer is higher for MOZART-4 than for RADM2 for most of the domain. The largest differences in O3 production can be seen over Germany, where net O3 production in MOZART-4 is seen to be higher than in RADM2 by 1.8 ppb h−1 (3.6 µg m−3 h−1) or more. We also show that while the two mechanisms exhibit similar NOx sensitivity, RADM2 is approximately twice as sensitive to increases in anthropogenic VOC emissions as MOZART-4. Additionally, we found that differences in reaction rate coefficients for inorganic gas-phase chemistry in MOZART-4 vs. RADM2 accounted for a difference of 8 µg m−3, or 40 % of the summertime difference in O3 predicted by the two mechanisms. Differences in deposition and photolysis schemes explained smaller differences in O3. Our results highlight the strong dependence of modeled surface O3 over Europe on the choice of gas-phase chemical mechanism, which we discuss in the context of overall uncertainties in prediction of ground-level O3 and its associated health impacts (via the health-related metrics MDA8 and SOMO35).

scholarly journals Description and evaluation of a detailed gas-phase chemistry scheme in the TM5-MP global chemistry transport model (r112)

2020 ◽  
Vol 13 (11) ◽  
pp. 5507-5548 ◽  
Author(s):  
Stelios Myriokefalitakis ◽  
Nikos Daskalakis ◽  
Angelos Gkouvousis ◽  
Andreas Hilboll ◽  
Twan van Noije ◽  
...  
Keyword(s):  
Gas Phase ◽  
Transport Model ◽  
Three Dimensional ◽  
Chemical Mechanism ◽  
Chemistry Transport Model ◽  
Chemical Mechanisms ◽  
Mixing Ratios ◽  
Gas Phase Chemistry ◽  
Time Requirements ◽  
Phase Chemistry

Abstract. This work documents and evaluates the tropospheric gas-phase chemical mechanism MOGUNTIA in the three-dimensional chemistry transport model TM5-MP. Compared to the modified CB05 (mCB05) chemical mechanism previously used in the model, MOGUNTIA includes a detailed representation of the light hydrocarbons (C1–C4) and isoprene, along with a simplified chemistry representation of terpenes and aromatics. Another feature implemented in TM5-MP for this work is the use of the Rosenbrock solver in the chemistry code, which can replace the classical Euler backward integration method of the model. Global budgets of ozone (O3), carbon monoxide (CO), hydroxyl radicals (OH), nitrogen oxides (NOx), and volatile organic compounds (VOCs) are analyzed, and their mixing ratios are compared with a series of surface, aircraft, and satellite observations for the year 2006. Both mechanisms appear to be able to satisfactorily represent observed mixing ratios of important trace gases, with the MOGUNTIA chemistry configuration yielding lower biases than mCB05 compared to measurements in most of the cases. However, the two chemical mechanisms fail to reproduce the observed mixing ratios of light VOCs, indicating insufficient primary emission source strengths, oxidation that is too fast, and/or a low bias in the secondary contribution to C2–C3 organics via VOC atmospheric oxidation. Relative computational memory and time requirements of the different model configurations are also compared and discussed. Overall, the MOGUNTIA scheme simulates a large suite of oxygenated VOCs that are observed in the atmosphere at significant levels. This significantly expands the possible applications of TM5-MP.

scholarly journals Aerosol mass yields of selected biogenic volatile organic compounds – a theoretical study with nearly explicit gas-phase chemistry

2019 ◽  
Vol 19 (22) ◽  
pp. 13741-13758
Author(s):  
Carlton Xavier ◽  
Anton Rusanen ◽  
Putian Zhou ◽  
Chen Dean ◽  
Lukas Pichelstorfer ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Gas Phase ◽  
Organic Compounds ◽  
Chemical Mechanism ◽  
Biogenic Volatile Organic Compounds ◽  
Gas Phase Chemistry ◽  
Mass Load ◽  
Volatile Organic ◽  
Phase Chemistry ◽  
Good Agreement

Abstract. In this study we modeled secondary organic aerosol (SOA) mass loadings from the oxidation (by O3, OH and NO3) of five representative biogenic volatile organic compounds (BVOCs): isoprene, endocyclic bond-containing monoterpenes (α-pinene and limonene), exocyclic double-bond compound (β-pinene) and a sesquiterpene (β-caryophyllene). The simulations were designed to replicate an idealized smog chamber and oxidative flow reactors (OFRs). The Master Chemical Mechanism (MCM) together with the peroxy radical autoxidation mechanism (PRAM) were used to simulate the gas-phase chemistry. The aim of this study was to compare the potency of MCM and MCM + PRAM in predicting SOA formation. SOA yields were in good agreement with experimental values for chamber simulations when MCM + PRAM was applied, while a stand-alone MCM underpredicted the SOA yields. Compared to experimental yields, the OFR simulations using MCM + PRAM yields were in good agreement for BVOCs oxidized by both O3 and OH. On the other hand, a stand-alone MCM underpredicted the SOA mass yields. SOA yields increased with decreasing temperatures and NO concentrations and vice versa. This highlights the limitations posed when using fixed SOA yields in a majority of global and regional models. Few compounds that play a crucial role (>95 % of mass load) in contributing to SOA mass increase (using MCM + PRAM) are identified. The results further emphasized that incorporating PRAM in conjunction with MCM does improve SOA mass yield estimation.

Different atmospheric O3 chemical environment in industrial regions of China, 2016: implications for emission control strategies and impacts on the globe in the future

2020 ◽  
Author(s):  
Zhenze Liu ◽  
Ruth M. Doherty ◽  
Oliver Wild ◽  
Fiona M. O’Connor
Keyword(s):  
Air Pollution ◽  
Gas Phase ◽  
Action Plan ◽  
Surface Ozone ◽  
Pollution Prevention ◽  
River Delta ◽  
Gas Phase Chemistry ◽  
Emission Controls ◽  
Industrial Regions ◽  
Phase Chemistry

<p>Surface ozone (O<sub>3</sub>) pollution became the main cause of atmospheric pollution over industrial regions in China since 2013, due to the effective mitigation of fine particulate matter (PM<sub>2.5</sub>) by stringent emission controls by Air Pollution Prevention and Control Action Plan (APPCAP). O<sub>3</sub>, as a secondary photochemical pollutant, poses a challenge to control due to its non-linear chemical relationship to precursors – nitrogen oxides (NO<sub>x</sub>), carbon monoxide (CO) and volatile organic compounds (VOCs).</p><p>We hence investigated the differences of atmospheric chemistry environment in the main industrial regions with high emissions – North China Plain (NCP), Yangtze River Delta (YRD), Pearl River Delta (PRD) and Chongqing - in summer 2016, China by using a global climate-chemistry model, based on United Kingdom Chemistry and Aerosol (UKCA). Anthropogenic Multi-resolution Emission Inventory for China (MEIC) 2013 and Hemispheric Transport of Air Pollution (HTAP) emissions 2010 for the rest of globe were used but scaled to 2016 regionally and nationally separately. In addition, we improved the gas-phase chemistry scheme by adding more highly reactive VOC tracers to better simulate regional pollution. Diurnal cycles of O<sub>3</sub> and NO<sub>x</sub> have been evaluated and the results show very good model-observation comparisons after modifying the gas-phase chemistry scheme. Radical (OH, RO<sub>2</sub> and HO<sub>2</sub>), NO<sub>x</sub> and VOC concentrations have also been examined. O<sub>3</sub> production rates and budgets calculated based on these show the highest production rate in YRD and the lowest in PRD due to different NO<sub>x</sub> and VOC concentration levels.</p><p>To investigate the O<sub>3 </sub>sensitivity — VOC limited or NO<sub>x</sub> limited, we quantified the O<sub>3</sub> response to VOCs and NO<sub>x</sub> in total 64 scenarios by scaling NO<sub>x </sub>and VOCs emissions. O<sub>3</sub> isopleths suggest that most regions are VOC limited, but the sensitivities vary. O<sub>3</sub> in YRD is more sensitive to NO<sub>x</sub> emission change but PRD can be effectively controlled by decreasing VOC emissions. The ratio of H<sub>2</sub>O<sub>2</sub> to HNO<sub>3</sub> is applied to provide a quick examination method of O<sub>3</sub> sensitivity. The contribution of O<sub>3</sub> from China to the global O<sub>3</sub> burden compared with other continents has also been quantified. The results show that the relatively higher O<sub>3</sub> concentration in Asia is mainly contributed by China, and O<sub>3</sub> becomes more sensitive to VOCs. The model allows us to provide a quantitative assessment of different emission controls on mitigating O<sub>3</sub> over China and the impacts of Chinese emissions on the global O<sub>3</sub> burden.</p>

scholarly journals Description and evaluation of a detailed gas-phase chemistry scheme in the TM5-MP global chemistry transport model (r112)

2020 ◽  
Author(s):  
Stelios Myriokefalitakis ◽  
Nikos Daskalakis ◽  
Angelos Gkouvousis ◽  
Andreas Hilboll ◽  
Twan van Noije ◽  
...  
Keyword(s):  
Gas Phase ◽  
Transport Model ◽  
Vertical Mixing ◽  
Three Dimensional ◽  
Chemical Mechanism ◽  
Aerosol Formation ◽  
Chemistry Transport Model ◽  
Mixing Ratios ◽  
Time Requirements ◽  
Phase Chemistry

Abstract. This work documents and evaluates the tropospheric gas-phase chemical mechanism MOGUNTIA in the three-dimensional chemistry transport model TM5-MP. Compared to the modified CB05 chemical mechanism previously used in the model, the MOGUNTIA includes a detailed representation of the light hydrocarbons (C1-C4) and isoprene, along with a simplified chemistry representation of terpenes and aromatics. Another feature implemented in TM5-MP for this work is the use of the Rosenbrock solver in the chemistry code, which can replace the classical Euler Backward Integration method of the model. Global budgets of ozone (O3), carbon monoxide (CO), hydroxyl radicals (OH), nitrogen oxides (NOX) and volatile organic compounds (VOCs) are here analyzed and their mixing ratios are compared with a series of surface, aircraft and satellite observations for the year 2006. Both mechanisms appear to be able to represent satisfactorily observed mixing ratios of important trace gases, with the MOGUNTIA chemistry configuration yielding lower biases compared to measurements in most of the cases. However, the two chemical mechanisms fail to reproduce the observed mixing ratios of light VOCs, indicating insufficient primary emission source strengths, too weak vertical mixing in the boundary layer, and/or a low bias in the secondary contribution of C2-C3 organics via VOC atmospheric oxidation. Relative computational memory and time requirements of the different model configurations are also compared and discussed. Overall, compared to other chemistry schemes in use in global CTMs, the MOGUNTIA scheme simulates a large suite of oxygenated VOCs that are observed in the atmosphere at significant levels and are involved in aerosol formation, expanding, thus, the applications of TM5-MP.

Impacts of monocyclic aromatics on regional and global tropospheric gas-phase chemistry

2020 ◽  
Author(s):  
Rolf Sander ◽  
David Cabrera-Perez ◽  
Sara Bacer ◽  
Sergey Gromov ◽  
Jos Lelieveld ◽  
...  
Keyword(s):  
East Asia ◽  
Gas Phase ◽  
Aromatic Compounds ◽  
General Circulation ◽  
Regional Scale ◽  
Circulation Model ◽  
Tropospheric Chemistry ◽  
Chemical Mechanism ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

<p>Aromatic compounds in the troposphere are reactive towards ozone<br>(O<sub>3</sub>), hydroxyl (OH) and other radicals. Here we present an<br>assessment of their impacts on the gas-phase chemistry, using the<br>general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). The<br>monocyclic aromatics considered in this study comprise benzene, toluene,<br>xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehyde<br>and lumped higher aromatics bearing more than 9 C atoms. On a global<br>scale, the estimated net changes are minor when aromatic compounds are<br>included in the chemical mechanism of our model. For instance, the<br>tropospheric burden of CO increases by about 6 %, and those of OH,<br>O<sub>3</sub>, and NO<sub>x</sub> (NO + NO<sub>2</sub>) decrease between<br>2 % and 14 %. The global mean changes are small partially because of<br>compensating effects between high- and low-NO<sub>x</sub> regions. The<br>largest change is predicted for glyoxal, which increases globally by 36<br>%. Significant regional changes are identified for several species. For<br>instance, glyoxal increases by 130 % in Europe and 260 % in East Asia,<br>respectively. Large increases in HCHO are also predicted in these<br>regions. In general, the influence of aromatics is particularly evident<br>in areas with high concentrations of NO<sub>x</sub>, with increases up<br>to 12 % in O<sub>3</sub> and 17 % in OH. Although the global impact of<br>aromatics is limited, our results indicate that aromatics can strongly<br>influence tropospheric chemistry on a regional scale, most significantly<br>in East Asia.</p>

scholarly journals Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

2017 ◽  
Vol 10 (10) ◽  
pp. 3661-3677 ◽  
Author(s):  
Louis Marelle ◽  
Jean-Christophe Raut ◽  
Kathy S. Law ◽  
Larry K. Berg ◽  
Jerome D. Fast ◽  
...  
Keyword(s):  
Gas Phase ◽  
Trace Gases ◽  
Surface Ozone ◽  
The Arctic ◽  
Surface Model ◽  
Gas Phase Chemistry ◽  
Surface Temperatures ◽  
Phase Chemistry ◽  
Mean Square Errors ◽  
Snow And Ice

Abstract. In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethyl sulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, and (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain–Fritsch + Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs) for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

scholarly journals Kinetic modeling of formation and evaporation of secondary organic aerosol from NO<sub>3</sub> oxidation of pure and mixed monoterpenes

2020 ◽  
Vol 20 (24) ◽  
pp. 15513-15535
Author(s):  
Thomas Berkemeier ◽  
Masayuki Takeuchi ◽  
Gamze Eris ◽  
Nga L. Ng
Keyword(s):  
Kinetic Model ◽  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Chemical Mechanism ◽  
Phase Reaction ◽  
Particle Phase ◽  
Environmental Chamber ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

Abstract. Organic aerosol constitutes a major fraction of the global aerosol burden and is predominantly formed as secondary organic aerosol (SOA). Environmental chambers have been used extensively to study aerosol formation and evolution under controlled conditions similar to the atmosphere, but quantitative prediction of the outcome of these experiments is generally not achieved, which signifies our lack in understanding of these results and limits their portability to large-scale models. In general, kinetic models employing state-of-the-art explicit chemical mechanisms fail to describe the mass concentration and composition of SOA obtained from chamber experiments. Specifically, chemical reactions including the nitrate radical (NO3) are a source of major uncertainty for assessing the chemical and physical properties of oxidation products. Here, we introduce a kinetic model that treats gas-phase chemistry, gas–particle partitioning, particle-phase oligomerization, and chamber vapor wall loss and use it to describe the oxidation of the monoterpenes α-pinene and limonene with NO3. The model can reproduce aerosol mass and nitration degrees in experiments using either pure precursors or their mixtures and infers volatility distributions of products, branching ratios of reactive intermediates and particle-phase reaction rates. The gas-phase chemistry in the model is based on the Master Chemical Mechanism (MCM) but trades speciation of single compounds for the overall ability of quantitatively describing SOA formation by using a lumped chemical mechanism. The complex branching into a multitude of individual products in MCM is replaced in this model with product volatility distributions and detailed peroxy (RO2) and alkoxy (RO) radical chemistry as well as amended by a particle-phase oligomerization scheme. The kinetic parameters obtained in this study are constrained by a set of SOA formation and evaporation experiments conducted in the Georgia Tech Environmental Chamber (GTEC) facility. For both precursors, we present volatility distributions of nitrated and non-nitrated reaction products that are obtained by fitting the kinetic model systematically to the experimental data using a global optimization method, the Monte Carlo genetic algorithm (MCGA). The results presented here provide new mechanistic insight into the processes leading to formation and evaporation of SOA. Most notably, the model suggests that the observed slow evaporation of SOA could be due to reversible oligomerization reactions in the particle phase. However, the observed non-linear behavior of precursor mixtures points towards a complex interplay of reversible oligomerization and kinetic limitations of mass transport in the particle phase, which is explored in a model sensitivity study. The methodologies described in this work provide a basis for quantitative analysis of multi-source data from environmental chamber experiments but also show that a large data pool is needed to fully resolve uncertainties in model parameters.

scholarly journals Improvements to the WRF-Chem model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

2017 ◽  
Author(s):  
Louis Marelle ◽  
Jean-Christophe Raut ◽  
Kathy S. Law ◽  
Larry K. Berg ◽  
Jerome D. Fast ◽  
...  
Keyword(s):  
Gas Phase ◽  
Trace Gases ◽  
Surface Ozone ◽  
The Arctic ◽  
Surface Model ◽  
Gas Phase Chemistry ◽  
Surface Temperatures ◽  
Phase Chemistry ◽  
Mean Square Errors ◽  
Snow And Ice

Abstract. In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethylsulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain-Fritsch + Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone, and airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface, root mean square errors (RMSE) for surface ozone and aerosols and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV-albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

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