A new version of the CNRM Chemistry-Climate Model, CNRM-CCM: description and improvements from the CCMVal-2 simulations

Abstract. This paper presents a new version of the Météo-France CNRM Chemistry-Climate Model, so-called CNRM-CCM. It includes some fundamental changes from the previous version (CNRM-ACM) which was extensively evaluated in the context of the CCMVal-2 validation activity. The most notable changes concern the radiative code of the GCM, and the inclusion of the detailed stratospheric chemistry of our Chemistry-Transport model MOCAGE on-line within the GCM. A 47-yr transient simulation (1960–2006) is the basis of our analysis. CNRM-CCM generates satisfactory dynamical and chemical fields in the stratosphere. Several shortcomings of CNRM-ACM simulations for CCMVal-2 that resulted from an erroneous representation of the impact of volcanic aerosols as well as from transport deficiencies have been eliminated. Remaining problems concern the upper stratosphere (5 to 1 hPa) where temperatures are too high, and where there are biases in the NO2, N2O5 and O3 mixing ratios. In contrast, temperatures at the tropical tropopause are too cold. These issues are addressed through the implementation of a more accurate radiation scheme at short wavelengths. Despite these problems we show that this new CNRM CCM is a useful tool to study chemistry-climate applications.

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A new version of the CNRM Chemistry-Climate Model, CNRM-CCM: description and improvements from the CCMVal-2 simulations

Geoscientific Model Development ◽

10.5194/gmd-4-873-2011 ◽

2011 ◽

Vol 4 (4) ◽

pp. 873-900 ◽

Cited By ~ 19

Author(s):

M. Michou ◽

D. Saint-Martin ◽

H. Teyssèdre ◽

A. Alias ◽

F. Karcher ◽

...

Keyword(s):

Climate Model ◽

Transport Model ◽

Chemistry Transport Model ◽

Mixing Ratios ◽

Tropical Tropopause ◽

On Line ◽

Volcanic Aerosols ◽

Chemical Fields ◽

The Impact ◽

Radiation Scheme

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The influence of biogenic emissions on upper-tropospheric methanol as revealed from space

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-6119-2007 ◽

2007 ◽

Vol 7 (24) ◽

pp. 6119-6129 ◽

Cited By ~ 44

Author(s):

G. Dufour ◽

S. Szopa ◽

D. A. Hauglustaine ◽

C. D. Boone ◽

C. P. Rinsland ◽

...

Keyword(s):

Northern Hemisphere ◽

Biomass Burning ◽

Transport Model ◽

Tropospheric Chemistry ◽

Biogenic Emissions ◽

Chemistry Transport Model ◽

Mixing Ratios ◽

Oxygenated Compounds ◽

Global Space ◽

The Impact

Abstract. The distribution and budget of oxygenated organic compounds in the atmosphere and their impact on tropospheric chemistry are still poorly constrained. Near-global space-borne measurements of seasonally resolved upper tropospheric profiles of methanol (CH3OH) by the ACE Fourier transform spectrometer provide a unique opportunity to evaluate our understanding of this important oxygenated organic species. ACE-FTS observations from March 2004 to August 2005 period are presented. These observations reveal the pervasive imprint of surface sources on upper tropospheric methanol: mixing ratios observed in the mid and high latitudes of the Northern Hemisphere reflect the seasonal cycle of the biogenic emissions whereas the methanol cycle observed in the southern tropics is highly influenced by biomass burning emissions. The comparison with distributions simulated by the state-of-the-art global chemistry transport model, LMDz-INCA, suggests that: (i) the background methanol (high southern latitudes) is correctly represented by the model considering the measurement uncertainties; (ii) the current emissions from the continental biosphere are underestimated during spring and summer in the Northern Hemisphere leading to an underestimation of modelled upper tropospheric methanol; (iii) the seasonal variation of upper tropospheric methanol is shifted to the fall in the model suggesting either an insufficient destruction of CH3OH (due to too weak chemistry and/or deposition) in fall and winter months or an unfaithful representation of transport; (iv) the impact of tropical biomass burning emissions on upper tropospheric methanol is rather well reproduced by the model. This study illustrates the potential of these first global profile observations of oxygenated compounds in the upper troposphere to improve our understanding of their global distribution, fate and budget.

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The contribution of natural and anthropogenic very short-lived species to stratospheric bromine

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-371-2012 ◽

2012 ◽

Vol 12 (1) ◽

pp. 371-380 ◽

Cited By ~ 51

Author(s):

R. Hossaini ◽

M. P. Chipperfield ◽

W. Feng ◽

T. J. Breider ◽

E. Atlas ◽

...

Keyword(s):

Transport Model ◽

Three Dimensional ◽

Chemical Transport Model ◽

Atmospheric Lifetime ◽

Tropical Tropopause Layer ◽

Mixing Ratios ◽

Tropical Tropopause ◽

Atmospheric Observations ◽

Surface Mixing ◽

The Impact

Abstract. We have used a global three-dimensional chemical transport model to quantify the impact of the very short-lived substances (VSLS) CHBr3, CH2Br2, CHBr2Cl, CHBrCl2, CH2BrCl and C2H5-Br on the bromine budget of the stratosphere. Atmospheric observations of these gases allow constraints on surface mixing ratios that, when incorporated into our model, contribute ~4.9–5.2 parts per trillion (ppt) of inorganic bromine (Bry) to the stratosphere. Of this total, ~76 % comes from naturally-emitted CHBr3 and CH2Br2. The remaining species individually contribute modest amounts. However, their accumulated total accounts for up to ~1.2 ppt of the supply and thus should not be ignored. We have compared modelled tropical profiles of a range of VSLS with observations from the recent 2009 NSF HIPPO-1 aircraft campaign. Modelled profiles agree reasonably well with observations from the surface to the lower tropical tropopause layer. We have also considered the poorly studied anthropogenic VSLS, C2H5Br, CH2BrCH2Br, n-C3H7Br and i-C3H7Br. We find the local atmospheric lifetime of these species in the tropical tropopause layer are ~183, 603, 39 and 49 days, respectively. These species, particularly C2H5Br and CH2BrCH2Br, would thus be important carriers of bromine to the stratosphere if emissions were to increase substantially. Our model shows ~70–73 % and ~80–85 % of bromine from these species in the tropical boundary layer can reach the lower stratosphere.

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Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-4493-2012 ◽

2012 ◽

Vol 12 (10) ◽

pp. 4493-4512 ◽

Cited By ~ 19

Author(s):

A. Klonecki ◽

M. Pommier ◽

C. Clerbaux ◽

G. Ancellet ◽

J.-P. Cammas ◽

...

Keyword(s):

Transport Model ◽

Source Region ◽

Specific Treatment ◽

Arctic Region ◽

The Arctic ◽

Chemistry Transport Model ◽

Mixing Ratios ◽

High Concentrations ◽

The Impact

Abstract. This work evaluates the IASI CO product against independent in-situ aircraft data from the MOZAIC program and the POLARCAT aircraft campaign. The validation is carried out by analysing the impact of assimilation of eight months of IASI CO columns retrieved for the period of May to December 2008 into the global chemistry transport model LMDz-INCA. A modelling system based on a sub-optimal Kalman filter was developed and a specific treatment that takes into account the representativeness of observations at the scale of the model grid is applied to the IASI CO columns and associated errors before their assimilation in the model. Comparisons of the assimilated CO profiles with in situ CO measurements indicate that the assimilation leads to a considerable improvement of the model simulations in the middle troposphere as compared with a control run with no assimilation. Model biases in the simulation of background values are reduced and improvement in the simulation of very high concentrations is observed. The improvement is due to the transport by the model of the information present in the IASI CO retrievals. Our analysis also shows the impact of assimilation of CO on the representation of transport into the Arctic region during the POLARCAT summer campaign. A considerable increase in CO mixing ratios over the Asian source region was observed when assimilation was used leading to much higher values of CO during the cross-pole transport episode. These higher values are in good agreement with data from the POLARCAT flights that sampled this plume.

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A quasi chemistry-transport model mode for EMAC

Geoscientific Model Development Discussions ◽

10.5194/gmdd-3-2189-2010 ◽

2010 ◽

Vol 3 (4) ◽

pp. 2189-2220

Author(s):

R. Deckert ◽

P. Jöckel ◽

V. Grewe ◽

K.-D. Gottschaldt ◽

P. Hoor

Keyword(s):

Water Vapor ◽

Nitric Acid ◽

Atmospheric Chemistry ◽

Transport Model ◽

Climate Simulation ◽

Chemistry Transport Model ◽

Mixing Ratios ◽

The Difference ◽

Stratospheric Clouds ◽

Chemical Fields

Abstract. A quasi chemistry-transport model mode (QCTM) is presented for the numerical chemistry-climate simulation system ECHAM/MESSy Atmospheric Chemistry (EMAC). It allows for a quantification of chemical signals through suppression of any feedback between chemistry and dynamics. Noise would otherwise interfere too strongly. The signal follows from the difference of two QCTM simulations, reference and sensitivity. These are fed with offline chemical fields as a substitute of the feedbacks between chemistry and dynamics: offline mixing ratios of radiatively active substances enter the radiation scheme (a), offline mixing ratios of nitric acid enter the scheme for re-partitioning and sedimentation from polar stratospheric clouds (b). Offline methane oxidation is the exclusive source of chemical water-vapor tendencies (c). Any set of offline fields suffices to suppress the feedbacks, though may be inconsistent with the simulation setup. An adequate set of offline climatologies can be produced from a non-QCTM simulation of the reference setup. Test simulations reveal the particular importance of adequate offline fields associated with (a). Inconsistencies from (b) are negligible when using adequate fields of nitric acid. Acceptably small inconsistencies come from (c), but should vanish for an adequate prescription of water vapor tendencies. Toggling between QCTM and non-QCTM is done via namelist switches and does not require a source code re-compilation.

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The contribution of natural and anthropogenic very short-lived species to stratospheric bromine

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-23859-2011 ◽

2011 ◽

Vol 11 (8) ◽

pp. 23859-23882

Author(s):

R. Hossaini ◽

M. P. Chipperfield ◽

W. Feng ◽

T. J. Breider ◽

E. Atlas ◽

...

Keyword(s):

Transport Model ◽

Three Dimensional ◽

Chemical Transport Model ◽

Atmospheric Lifetime ◽

Tropical Tropopause Layer ◽

Mixing Ratios ◽

Tropical Tropopause ◽

Atmospheric Observations ◽

Surface Mixing ◽

The Impact

Abstract. We have used a global three-dimensional chemical transport model to quantify the impact of the very short-lived species (VSLS) CHBr3, CH2Br2, CHBr2Cl, CHBrCl2, CH2BrCl and C2H5Br on the bromine budget of the stratosphere. Atmospheric observations of these gases allow constraints on surface mixing ratios that, when incorporated into our model, contribute ~ 4.9–5.2 parts per trillion (ppt) of inorganic bromine (Bry) to the stratosphere. Of this total, ~ 76 % comes from naturally-emitted CHBr3 and CH2Br2. The remaining species individually contribute modest amounts. However, their accumulated total accounts for up to ~ 1.2 ppt of the supply and thus should not be ignored. We have compared modelled tropical profiles of a range of VSLS with observations from the recent 2009 NSF HIPPO-1 aircraft campaign. Modelled profiles agree reasonably well with observations from the surface to the lower tropical tropopause layer. We have also considered the poorly studied anthropogenic VSLS, C2H5Br, CH2BrCH2Br, n-C3H7Br and i-C3H7Br. We find the local atmospheric lifetime of these species in the tropical tropopause layer are ~ 183, 603, 39 and 49 days, respectively. These species, particularly C2H5Br and CH2BrCH2Br, would thus be important carriers of bromine to the stratosphere if emissions were to increase substantially. Our model shows ~ 70–73 % and ~ 80–85 % of bromine from these species in the tropical boundary layer can reach the lower stratosphere.

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The On-Line Integrated Mesoscale Chemistry Model BOLCHEM

Atmosphere ◽

10.3390/atmos12020192 ◽

2021 ◽

Vol 12 (2) ◽

pp. 192

Author(s):

Rita Cesari ◽

Tony Christian Landi ◽

Massimo D’Isidoro ◽

Mihaela Mircea ◽

Felicita Russo ◽

...

Keyword(s):

Correlation Coefficient ◽

Transport Model ◽

Horizontal Resolution ◽

Integration Step ◽

Chemistry Transport Model ◽

European Environmental Agency ◽

On Line ◽

One Year ◽

Pm2.5 And Pm10 ◽

Monitoring Service

This work presents the on-line coupled meteorology–chemistry transport model BOLCHEM, based on the hydrostatic meteorological BOLAM model, the gas chemistry module SAPRC90, and the aerosol dynamic module AERO3. It includes parameterizations to describe natural source emissions, dry and wet removal processes, as well as the transport and dispersion of air pollutants. The equations for different processes are solved on the same grid during the same integration step, by means of a time-split scheme. This paper describes the model and its performance at horizontal resolution of 0.2∘× 0.2∘ over Europe and 0.1∘× 0.1∘ in a nested configuration over Italy, for one year run (December 2009–November 2010). The model has been evaluated against the AIRBASE data of the European Environmental Agency. The basic statistics for higher resolution simulations of O3, NO2 and particulate matter concentrations (PM2.5 and PM10) have been compared with those from Copernicus Atmosphere Monitoring Service (CAMS) ensemble median. In summer, for O3 we found a correlation coefficient R of 0.72 and mean bias of 2.15 over European domain and a correlation coefficient R of 0.67 and mean bias of 2.36 over Italian domain. PM10 and PM2.5 are better reproduced in the winter, the latter with a correlation coefficient R of 0.66 and the mean bias MB of 0.35 over Italian domain.

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Chemistry–climate interactions of aerosol nitrate from lightning

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-1125-2017 ◽

2017 ◽

Vol 17 (2) ◽

pp. 1125-1142 ◽

Cited By ~ 8

Author(s):

Holger Tost

Keyword(s):

Climate Model ◽

Statistical Significance ◽

Aerosol Particles ◽

Internal Variability ◽

Aerosol Size Distribution ◽

Upper Troposphere ◽

Uncertainty Range ◽

Mixing Ratios ◽

Microphysical Properties ◽

The Impact

Abstract. Lightning represents one of the dominant emission sources for NOx in the troposphere. The direct release of oxidised nitrogen in the upper troposphere does not only affect ozone formation, but also chemical and microphysical properties of aerosol particles in this region. This study investigates the direct impact of LNOx emissions on upper-tropospheric nitrate using a global chemistry climate model. The simulation results show a substantial influence of the lightning emissions on the mixing ratios of nitrate aerosol in the upper troposphere of more than 50 %. In addition to the impact on nitrate, lightning substantially affects the oxidising capacity of the atmosphere with substantial implications for gas-phase sulfate formation and new particle formation in the upper troposphere. In conjunction with the condensation of nitrates, substantial differences in the aerosol size distribution occur in the upper troposphere as a consequence of lightning. This has implications for the extinction properties of the aerosol particles and for the cloud optical properties. While the extinction is generally slightly enhanced due to the LNOx emissions, the response of the clouds is ambiguous due to compensating effects in both liquid and ice clouds. Resulting shortwave flux perturbations are of ∼ −100 mW m−2 as determined from several sensitivity scenarios, but an uncertainty range of almost 50 % has to be defined due to the large internal variability of the system and the uncertainties in the multitude of involved processes. Despite the clear statistical significance of the influence of lightning on the nitrate concentrations, the robustness of the findings gradually decreases towards the determination of the radiative flux perturbations.

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Towards an online-coupled chemistry-climate model: evaluation of trace gases and aerosols in COSMO-ART

Geoscientific Model Development ◽

10.5194/gmd-4-1077-2011 ◽

2011 ◽

Vol 4 (4) ◽

pp. 1077-1102 ◽

Cited By ~ 63

Author(s):

C. Knote ◽

D. Brunner ◽

H. Vogel ◽

J. Allan ◽

A. Asmi ◽

...

Keyword(s):

Chemical Composition ◽

Size Distribution ◽

Urban Areas ◽

Climate Model ◽

Transport Model ◽

Climate Impacts ◽

Chemistry Transport Model ◽

Pm2.5 And Pm10 ◽

Phase Chemistry ◽

Aerosol Chemical Composition

Abstract. The online-coupled, regional chemistry transport model COSMO-ART is evaluated for periods in all seasons against several measurement datasets to assess its ability to represent gaseous pollutants and ambient aerosol characteristics over the European domain. Measurements used in the comparison include long-term station observations, satellite and ground-based remote sensing products, and complex datasets of aerosol chemical composition and number size distribution from recent field campaigns. This is the first time these comprehensive measurements of aerosol characteristics in Europe are used to evaluate a regional chemistry transport model. We show a detailed analysis of the simulated size-resolved chemical composition under different meteorological conditions. Mean, variability and spatial distribution of the concentrations of O3 and NOx are well reproduced. SO2 is found to be overestimated, simulated PM2.5 and PM10 levels are on average underestimated, as is AOD. We find indications of an overestimation of shipping emissions. Time evolution of aerosol chemical composition is captured, although some biases are found in relative composition. Nitrate aerosol components are on average overestimated, and sulfates underestimated. The accuracy of simulated organics depends strongly on season and location. While strongly underestimated during summer, organic mass is comparable in spring and autumn. We see indications for an overestimated fractional contribution of primary organic matter in urban areas and an underestimation of SOA at many locations. Aerosol number concentrations compare well with measurements for larger size ranges, but overestimations of particle number concentration with factors of 2–5 are found for particles smaller than 50 nm. Size distribution characteristics are often close to measurements, but show discrepancies at polluted sites. Suggestions for further improvement of the modeling system consist of the inclusion of a revised secondary organic aerosols scheme, aqueous-phase chemistry and improved aerosol boundary conditions. Our work sets the basis for subsequent studies of aerosol characteristics and climate impacts with COSMO-ART, and highlights areas where improvements are necessary for current regional modeling systems in general.

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Comparison of Airborne Peroxy Radical Measurements with MECO(n) model simulation during EMeRGe in Europe

10.5194/egusphere-egu2020-18247 ◽

2020 ◽

Author(s):

Yangzhuoran Liu ◽

Mariano Mertens ◽

Maria Dolores Andrés Hernández ◽

Midhun George ◽

Vladyslav Nenakhov ◽

...

Keyword(s):

Climate Model ◽

Model Simulation ◽

Peroxy Radical ◽

Photochemical Activity ◽

Peroxy Radicals ◽

Transport And Transformation ◽

Air Masses ◽

Mixing Ratios ◽

Airborne Measurement ◽

On Line

Observations of tropospheric peroxy radicals are a key point for interpretation of the processing and transformation of polluted outflows from major populated centres (MPCs). A series of European MPCs are investigated by the project EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional and Global scales). With this objective two airborne campaigns using the research platform HALO (High Altitude and LOng range aircraft) were carried out over Europe in summer 2017 and over east Asia in the intermonsoon period in 2018. The Institute of Environmental Physics (IUP) in Bremen (Germany) participated in both EMeRGe campaigns with the airborne measurement of the total sum of peroxy radicals, RO2*, by using &#160;the home made PeRCEAS instrument based on the combination of the PERCA (peroxy radical chemical amplification)&#160; and CRDS (cavity ring down spectroscopy) techniques. One of the main purposes of the campaigns was the investigation of the characteristics and chemical transformation of MPC outflows at the local and regional scales.During the EMeRGe campaign in Europe, air masses of different photochemical activity were measured, where RO2* mixing ratios up to 100pptv being observed. In the present study the RO2* observations for six measurement flights of EMeRGe in Europe have been compared with RO2 (here defined as the sum of HO2 + CH3O2 + ISOOH + CH3CO3 + CH3COCH2O2) simulated by using the MECO(n) model.MECO(n) (MESSy-fied ECHAM and COSMO models nested n times), is &#160;a global/regional chemistry-climate model developed by the MESSy consortium, which couples on-line the global chemistry-climate model EMAC with the regional chemistry-climate model COSMO-CLM/MESSy. The same anthropogenic emission inventory (EDGAR 4.3.1) as well as the same solver for chemical kinetics, involving complex tropospheric and stratospheric chemistry, are applied in EMAC and COSMO-CLM/MESSy.Overall, the agreement between the measurements and model is reasonable for RO2* observations below 40 pptv. Events with higher mixing ratios seem not to be well reproduced by the model but underestimated. Further details on the modelling and the result of the comparison will be presented.

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