A fast stratospheric chemistry solver: the E4CHEM submodel for the atmospheric chemistry global circulation model EMAC

Abstract. The atmospheric chemistry general circulation model ECHAM5/MESSy (EMAC) and the atmospheric chemistry box model CAABA are extended by a computationally very efficient submodel for atmospheric chemistry, E4CHEM. It focuses on stratospheric chemistry but also includes background tropospheric chemistry. It is based on the chemistry of MAECHAM4-CHEM and is intended to serve as a simple and fast alternative to the flexible but also computationally more demanding submodel MECCA. In a model setup with E4CHEM, EMAC is now also suitable for simulations of longer time scales. The reaction mechanism contains basic O3, CH4, CO, HOx, NOx, and ClOx gas phase chemistry. In addition, E4CHEM includes optional fast routines for heterogeneous reactions on sulphate aerosols and polar stratospheric clouds (substituting the existing submodels PSC and HETCHEM), and scavenging (substituting the existing submodel SCAV). We describe the implementation of E4CHEM into the MESSy structure of CAABA and EMAC. For some species the steady state in the box model differs by up to 100% when compared to results from CAABA/MECCA due to different reaction rates. After an update of the reaction rates in E4CHEM the mixing ratios in both boxmodel and 3-D model simulations are in satisfactory agreement with the results from a simulation where MECCA with a similar chemistry scheme was employed. Finally, a comparison against a simulation with a more complex and already evaluated chemical mechanism is presented in order to discuss shortcomings associated with the simplification of the chemical mechanism.

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A fast stratospheric chemistry solver: the E4CHEM submodel for the atmospheric chemistry global circulation model EMAC

Geoscientific Model Development Discussions ◽

10.5194/gmdd-3-181-2010 ◽

2010 ◽

Vol 3 (1) ◽

pp. 181-200

Author(s):

A. J. G. Baumgaertner ◽

P. Jöckel ◽

B. Steil ◽

H. Tost ◽

R. Sander

Keyword(s):

Atmospheric Chemistry ◽

General Circulation ◽

Circulation Model ◽

Reaction Rates ◽

Heterogeneous Reactions ◽

Tropospheric Chemistry ◽

Box Model ◽

Chemical Mechanism ◽

Global Circulation Model ◽

Stratospheric Chemistry

Abstract. The atmospheric chemistry general circulation model ECHAM5/MESSy (EMAC) and the atmospheric chemistry box model CAABA are extended by a computationally very efficient submodel for atmospheric chemistry, E4CHEM. It focuses on stratospheric chemistry but also includes background tropospheric chemistry. It is based on the chemistry of MAECHAM4-CHEM and is intended to serve as a simple and fast alternative to the flexible but also computationally more demanding submodel MECCA. In a model setup with E4CHEM, EMAC is now also suitable for simulations of longer time scales. The reaction mechanism contains basic O3, CH4, CO, HOx, NOx and ClOx gas phase chemistry. In addition, E4CHEM includes optional fast routines for heterogeneous reactions on sulphate aerosols and polar stratospheric clouds (substituting the existing submodels PSC and HETCHEM), and scavenging (substituting the existing submodel SCAV). We describe the implementation of E4CHEM into the MESSy structure of CAABA and EMAC. For some species the steady state in the box model differs by up to 100% when compared to results from CAABA/MECCA due to different reaction rates. After an update of the reaction rates in E4CHEM the mixing ratios in both boxmodel and 3-D model simulations are in satisfactory agreement with the results from a simulation where MECCA with a similar chemistry scheme was employed. Finally, a comparison against a simulation with a more complex and already evaluated chemical mechanism is presented in order to discuss shortcomings associated with the simplification of the chemical mechanism.

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Technical note: The new comprehensive atmospheric chemistry module MECCA

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-445-2005 ◽

2005 ◽

Vol 5 (2) ◽

pp. 445-450 ◽

Cited By ~ 230

Author(s):

R. Sander ◽

A. Kerkweg ◽

P. Jöckel ◽

J. Lelieveld

Keyword(s):

Atmospheric Chemistry ◽

General Circulation ◽

Circulation Model ◽

Technical Note ◽

Heterogeneous Reactions ◽

Chemical Mechanism ◽

Sulfur Chemistry ◽

Gas Phase Chemistry ◽

Phase Chemistry ◽

Atmospheric Reaction

Abstract. In this technical note we present the multi-purpose atmospheric chemistry model MECCA. Owing to its versatility and modular structure, it can be used for tropospheric as well as stratospheric chemistry calculations. Extending the code to other domains (e.g. mesospheric or oceanic chemistry) is easily possible. MECCA contains a comprehensive atmospheric reaction mechanism that currently includes: 1) the basic O3, CH4, HOx, and NOx chemistry, 2) non-methane hydrocarbon (NMHC) chemistry, 3) halogen (Cl, Br, I) chemistry, and 4) sulfur chemistry. Not only gas-phase chemistry but also aqueous-phase and heterogeneous reactions are considered. Arbitrary subsets of the comprehensive mechanism can be selected according to the research objectives. The program code resulting from the chemical mechanism can easily be used in any model, from a simple box model to a comprehensive global general circulation model.

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Technical Note: The new comprehensive atmospheric chemistry module MECCA

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-4-7167-2004 ◽

2004 ◽

Vol 4 (6) ◽

pp. 7167-7180

Author(s):

R. Sander ◽

R. Kerkweg ◽

P. Jöckel ◽

J. Lelieveld

Keyword(s):

Atmospheric Chemistry ◽

General Circulation ◽

Circulation Model ◽

Technical Note ◽

Heterogeneous Reactions ◽

Chemical Mechanism ◽

Sulfur Chemistry ◽

Gas Phase Chemistry ◽

Phase Chemistry ◽

Atmospheric Reaction

Abstract. In this technical note we present the multi-purpose atmospheric chemistry model MECCA. Owing to its versatility and modular structure, it can be used for tropospheric as well as stratospheric chemistry calculations. Extending the code to other domains (e.g. mesospheric or oceanic chemistry) is easily possible. MECCA contains a comprehensive atmospheric reaction mechanism that currently includes: 1) the basic O3, CH4, HOx, and NOx, chemistry, 2) non-methane hydrocarbon (NMHC) chemistry, 3) halogen (Cl, Br, I) chemistry, and 4) sulfur chemistry. Not only gas-phase chemistry but also aqueous-phase and heterogeneous reactions are considered. Arbitrary subsets of the comprehensive mechanism can be selected according to the research objectives. The program code resulting from the chemical mechanism can easily be used in any kind of model, from a simple box model to a sophisticated global general circulation model.

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Consistent simulation of bromine chemistry from the marine boundary layer to the stratosphere – Part 1: Model description, sea salt aerosols and pH

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-5899-2008 ◽

2008 ◽

Vol 8 (19) ◽

pp. 5899-5917 ◽

Cited By ~ 24

Author(s):

A. Kerkweg ◽

P. Jöckel ◽

A. Pozzer ◽

H. Tost ◽

R. Sander ◽

...

Keyword(s):

Size Distribution ◽

Atmospheric Chemistry ◽

General Circulation ◽

Circulation Model ◽

Reaction Rates ◽

Sea Salt ◽

Aerosol Size Distribution ◽

Model Description ◽

Aerosol Chemistry ◽

Coarse Mode

Abstract. This is the first article of a series presenting a detailed analysis of bromine chemistry simulated with the atmospheric chemistry general circulation model ECHAM5/MESSy. Release from sea salt is an important bromine source, hence the model explicitly calculates aerosol chemistry and phase partitioning for coarse mode aerosol particles. Many processes including chemical reaction rates are influenced by the particle size distribution, and aerosol associated water strongly affects the aerosol pH. Knowledge of the aerosol pH is important as it determines the aerosol chemistry, e.g., the efficiency of sulphur oxidation and bromine release. Here, we focus on the simulated sea salt aerosol size distribution and the coarse mode aerosol pH. A comparison with available field data shows that the simulated aerosol distributions agree reasonably well within the range of measurements. In spite of the small number of aerosol pH measurements and the uncertainty in its experimental determination, the simulated aerosol pH compares well with the observations. The aerosol pH ranges from alkaline aerosol in areas of strong production down to pH-values of 1 over regions of medium sea salt production and high levels of gas phase acids, mostly polluted regions over the oceans in the Northern Hemisphere.

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The influence of the vertical distribution of emissions on tropospheric chemistry

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-16051-2009 ◽

2009 ◽

Vol 9 (4) ◽

pp. 16051-16083

Author(s):

A. Pozzer ◽

P. Jöckel ◽

J. Van Aardenne

Keyword(s):

Vertical Distribution ◽

Atmospheric Chemistry ◽

General Circulation ◽

Circulation Model ◽

Tropospheric Chemistry ◽

Aircraft Observations ◽

Field Campaigns ◽

The Vertical Distribution ◽

Lower Correlation ◽

Model Layer

Abstract. The atmospheric chemistry general circulation model EMAC (ECHAM5/MESSy atmospheric chemistry) is used to investigate the effect of height dependent emissions on tropospheric chemistry. In a sensitivity simulation, anthropogenic and biomass burning emissions are released in the lowest model layer. The resulting tracer distributions are compared to those of a former simulation applying height dependent emissions. Although the differences between the two simulations in the free troposphere are small (less than 5%), large differences are present in polluted regions at the surface, in particular for NOx (more than 100%) and non-methane hydrocarbons (up to 30%), whereas for OH the differences at the same locations are somewhat lower (15%). Global ozone formation is virtually unaffected by the choice of the vertical distribution of emissions. Nevertheless, local ozone changes can be up to 30%. Model results of both simulations are further compared to observations from field campaigns and to data from measurement stations. The two simulations show no significant differences when compared to aircraft observations. In contrast, for measurements from surface stations, the simulation with emissions in the lowest model layer gives a 20% lower correlation to the observations compared to the simulation with height dependent emissions.

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

10.5194/egusphere-egu2020-5114 ◽

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

Aromatic compounds in the troposphere are reactive towards ozone (O3), hydroxyl (OH) and other radicals. Here we present an assessment of their impacts on the gas-phase chemistry, using the general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). The monocyclic aromatics considered in this study comprise benzene, toluene, xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehyde and lumped higher aromatics bearing more than 9 C atoms. On a global scale, the estimated net changes are minor when aromatic compounds are included in the chemical mechanism of our model. For instance, the tropospheric burden of CO increases by about 6 %, and those of OH, O3, and NOx (NO + NO2) decrease between 2 % and 14 %. The global mean changes are small partially because of compensating effects between high- and low-NOx regions. The largest change is predicted for glyoxal, which increases globally by 36 %. Significant regional changes are identified for several species. For instance, glyoxal increases by 130 % in Europe and 260 % in East Asia, respectively. Large increases in HCHO are also predicted in these regions. In general, the influence of aromatics is particularly evident in areas with high concentrations of NOx, with increases up to 12 % in O3 and 17 % in OH. Although the global impact of aromatics is limited, our results indicate that aromatics can strongly influence tropospheric chemistry on a regional scale, most significantly in East Asia.

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Simulation of tropospheric chemistry and aerosols with the climate model EC-Earth

Geoscientific Model Development Discussions ◽

10.5194/gmdd-7-1933-2014 ◽

2014 ◽

Vol 7 (2) ◽

pp. 1933-2006 ◽

Cited By ~ 5

Author(s):

T. P. C. van Noije ◽

P. Le Sager ◽

A. J. Segers ◽

P. F. J. van Velthoven ◽

M. C. Krol ◽

...

Keyword(s):

Aerosol Optical Depth ◽

Optical Depth ◽

Atmospheric Chemistry ◽

General Circulation ◽

Data Exchange ◽

Climate Model ◽

Global Climate Model ◽

Surface Ozone ◽

Circulation Model ◽

Tropospheric Chemistry

Abstract. We have integrated the atmospheric chemistry and transport model TM5 into the global climate model EC-Earth version 2.4. We present an overview of the TM5 model and the two-way data exchange between TM5 and the integrated forecasting system (IFS) model from the European Centre for Medium-Range Weather Forecasts (ECMWF), the atmospheric general circulation model of EC-Earth. In this paper we evaluate the simulation of tropospheric chemistry and aerosols in a one-way coupled configuration. We have carried out a decadal simulation for present-day conditions and calculated chemical budgets and climatologies of tracer concentrations and aerosol optical depth. For comparison we have also performed offline simulations driven by meteorological fields from ECMWF's ERA-Interim reanalysis and output from the EC-Earth model itself. Compared to the offline simulations, the online-coupled system produces more efficient vertical mixing in the troposphere, which likely reflects an improvement of the treatment of cumulus convection. The chemistry in the EC-Earth simulations is affected by the fact that the current version of EC-Earth produces a cold bias with too dry air in large parts of the troposphere. Compared to the ERA-Interim driven simulation, the oxidizing capacity in EC-Earth is lower in the tropics and higher in the extratropics. The methane lifetime is 7% higher in EC-Earth, but remains well within the range reported in the literature. We evaluate the model by comparing the simulated climatologies of surface carbon monoxide, tropospheric and surface ozone, and aerosol optical depth against observational data. The work presented in this study is the first step in the development of EC-Earth into an Earth system model with fully interactive atmospheric chemistry and aerosols.

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The atmospheric chemistry general circulation model ECHAM5/MESSy1: consistent simulation of ozone from the surface to the mesosphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-6-6957-2006 ◽

2006 ◽

Vol 6 (4) ◽

pp. 6957-7050 ◽

Cited By ~ 9

Author(s):

P. Jöckel ◽

H. Tost ◽

A. Pozzer ◽

C. Brühl ◽

J. Buchholz ◽

...

Keyword(s):

General Circulation Model ◽

Atmospheric Chemistry ◽

General Circulation ◽

Middle Atmosphere ◽

Circulation Model ◽

Tropospheric Chemistry ◽

Atmospheric Composition ◽

Quasi Biennial Oscillation ◽

Wave Forcing ◽

Characteristic Features

Abstract. The new Modular Earth Submodel System (MESSy) describes atmospheric chemistry and meteorological processes in a modular framework, following strict coding standards. It has been coupled to the ECHAM5 general circulation model, which has been slightly modified for this purpose. A 90-layer model version up to 0.01 hPa was used at T42 resolution (~2.8 latitude and longitude) to simulate the lower and middle atmosphere. The model meteorology has been tested to check the influence of the changes to ECHAM5 and the radiation interactions with the new representation of atmospheric composition. A Newtonian relaxation technique was applied in the tropospheric part of the domain to weakly nudge the model towards the analysed meteorology during the period 1998–2005. It is shown that the tropospheric wave forcing of the stratosphere in the model suffices to reproduce the Quasi-Biennial Oscillation and major stratospheric warming events leading e.g. to the vortex split over Antarctica in 2002. Characteristic features such as dehydration and denitrification caused by the sedimentation of polar stratospheric cloud particles and ozone depletion during winter and spring are simulated accurately, although ozone loss in the lower polar stratosphere is slightly underestimated. The model realistically simulates stratosphere-troposphere exchange processes as indicated by comparisons with satellite and in situ measurements. The evaluation of tropospheric chemistry presented here focuses on the distributions of ozone, hydroxyl radicals, carbon monoxide and reactive nitrogen compounds. In spite of minor shortcomings, mostly related to the relatively coarse T42 resolution and the neglect of interannual changes in biomass burning emissions, the main characteristics of the trace gas distributions are generally reproduced well. The MESSy submodels and the ECHAM5/MESSy1 model output are available through the internet on request.

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The atmospheric chemistry general circulation model ECHAM5/MESSy1: consistent simulation of ozone from the surface to the mesosphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-5067-2006 ◽

2006 ◽

Vol 6 (12) ◽

pp. 5067-5104 ◽

Cited By ~ 432

Author(s):

P. Jöckel ◽

H. Tost ◽

A. Pozzer ◽

C. Brühl ◽

J. Buchholz ◽

...

Keyword(s):

General Circulation Model ◽

Atmospheric Chemistry ◽

General Circulation ◽

Middle Atmosphere ◽

Circulation Model ◽

Tropospheric Chemistry ◽

Atmospheric Composition ◽

Direct Evaluation ◽

Quasi Biennial Oscillation

Abstract. The new Modular Earth Submodel System (MESSy) describes atmospheric chemistry and meteorological processes in a modular framework, following strict coding standards. It has been coupled to the ECHAM5 general circulation model, which has been slightly modified for this purpose. A 90-layer model setup up to 0.01 hPa was used at spectral T42 resolution to simulate the lower and middle atmosphere. With the high vertical resolution the model simulates the Quasi-Biennial Oscillation. The model meteorology has been tested to check the influence of the changes to ECHAM5 and the radiation interactions with the new representation of atmospheric composition. In the simulations presented here a Newtonian relaxation technique was applied in the tropospheric part of the domain to weakly nudge the model towards the analysed meteorology during the period 1998–2005. This allows an efficient and direct evaluation with satellite and in-situ data. It is shown that the tropospheric wave forcing of the stratosphere in the model suffices to reproduce major stratospheric warming events leading e.g. to the vortex split over Antarctica in 2002. Characteristic features such as dehydration and denitrification caused by the sedimentation of polar stratospheric cloud particles and ozone depletion during winter and spring are simulated well, although ozone loss in the lower polar stratosphere is slightly underestimated. The model realistically simulates stratosphere-troposphere exchange processes as indicated by comparisons with satellite and in situ measurements. The evaluation of tropospheric chemistry presented here focuses on the distributions of ozone, hydroxyl radicals, carbon monoxide and reactive nitrogen compounds. In spite of minor shortcomings, mostly related to the relatively coarse T42 resolution and the neglect of inter-annual changes in biomass burning emissions, the main characteristics of the trace gas distributions are generally reproduced well. The MESSy submodels and the ECHAM5/MESSy1 model output are available through the internet on request.

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Influence of aromatics on tropospheric gas-phase composition

10.5194/acp-2020-461 ◽

2020 ◽

Cited By ~ 1

Author(s):

Domenico Taraborrelli ◽

David Cabrera-Perez ◽

Sara Bacer ◽

Sergey Gromov ◽

Jos Lelieveld ◽

...

Keyword(s):

East Asia ◽

Gas Phase ◽

Atmospheric Chemistry ◽

General Circulation ◽

Anthropogenic Activities ◽

Regional Scale ◽

Circulation Model ◽

Significant Loss ◽

Tropospheric Chemistry ◽

The Impact

Abstract. Aromatics contribute a significant fraction to organic compounds in the troposphere and are mainly emitted by anthropogenic activities and biomass burning. Their oxidation in lab experiments is known to lead to the formation of ozone and aerosol precursors. However, their overall impact on tropospheric composition is uncertain as it depends on transport, multiphase chemistry, and removal processes of the oxidation intermediates. Representation of aromatics in global atmospheric models has been either neglected or highly simplified. Here, we present an assessment of their impact on the gas-phase chemistry, using the general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). We employ a comprehensive kinetic model to represent the oxidation of the following monocyclic aromatics: benzene, toluene, xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehyde, and lumped higher aromatics that contain more than 9 C atoms. Significant regional changes are identified for several species. For instance, glyoxal increases by 130 % in Europe and 260 % in East Asia, respectively. Large increases in HCHO are also predicted in these regions. In general, the influence of aromatics is particularly evident in areas with high concentrations of NOx, with increases up to 12 % in O3 and 17 % in OH. On a global scale, the estimated net changes are minor when aromatic compounds are included in our model. For instance, the tropospheric burden of CO increases by about 6 %, while the burdens of OH, O3, and NOx (NO + NO2) decrease between 3 % and 9 %. The global mean changes are small, partially because of compensating effects between high- and low-NOx regions. The largest change is predicted for the important aerosol precursor glyoxal, which increases globally by 36 %. In contrast to other studies, the net change in tropospheric ozone is predicted to be negative, −3 % globally. This change is larger in the northern hemisphere where global models usually show positive biases. We find that the reaction with phenoxy radicals is a significant loss for ozone, of the order of 200–300 Tg/yr, which is similar to the estimated ozone loss due to bromine chemistry. Although the net global impact of aromatics is limited, our results indicate that aromatics can strongly influence tropospheric chemistry on a regional scale, most significantly in East Asia. An analysis of the main model uncertainties related to oxidation and emissions suggests that the impact of aromatics may even be significantly larger.

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