The global chemistry transport model TM5: description and evaluation of the tropospheric chemistry version 3.0

Abstract. We present a comprehensive description and benchmark evaluation of the tropospheric chemistry version of the global chemistry transport model TM5 (Tracer Model 5, version TM5-chem-v3.0). A full description is given concerning the photochemical mechanism, the interaction with aerosol, the treatment of the stratosphere, the wet and dry deposition parameterizations, and the applied emissions. We evaluate the model against a suite of ground-based, satellite, and aircraft measurements of components critical for understanding global photochemistry for the year 2006. The model exhibits a realistic oxidative capacity at a global scale. The methane lifetime is ~8.9 years with an associated lifetime of methyl chloroform of 5.86 years, which is similar to that derived using an optimized hydroxyl radical field. The seasonal cycle in observed carbon monoxide (CO) is well simulated at different regions across the globe. In the Northern Hemisphere CO concentrations are underestimated by about 20 ppbv in spring and 10 ppbv in summer, which is related to missing chemistry and underestimated emissions from higher hydrocarbons, as well as to uncertainties in the seasonal variation of CO emissions. The model also captures the spatial and seasonal variation in formaldehyde tropospheric columns as observed by SCIAMACHY. Positive model biases over the Amazon and eastern United States point to uncertainties in the isoprene emissions as well as its chemical breakdown. Simulated tropospheric nitrogen dioxide columns correspond well to observations from the Ozone Monitoring Instrument in terms of its seasonal and spatial variability (with a global spatial correlation coefficient of 0.89), but TM5 fields are lower by 25–40%. This is consistent with earlier studies pointing to a high bias of 0–30% in the OMI retrievals, but uncertainties in the emission inventories have probably also contributed to the discrepancy. TM5 tropospheric nitrogen dioxide profiles are in good agreement (within ~0.1 ppbv) with in situ aircraft observations from the INTEX-B campaign over (the Gulf of) Mexico. The model reproduces the spatial and seasonal variation in background surface ozone concentrations and tropospheric ozone profiles from the World Ozone and Ultraviolet Radiation Data Centre to within 10 ppbv, but at several tropical stations the model tends to underestimate ozone in the free troposphere. The presented model results benchmark the TM5 tropospheric chemistry version, which is currently in use in several international cooperation activities, and upon which future model improvements will take place.

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The global chemistry transport model TM5: description and evaluation of the tropospheric chemistry version 3.0

Geoscientific Model Development ◽

10.5194/gmd-3-445-2010 ◽

2010 ◽

Vol 3 (2) ◽

pp. 445-473 ◽

Cited By ~ 188

Author(s):

V. Huijnen ◽

J. Williams ◽

M. van Weele ◽

T. van Noije ◽

M. Krol ◽

...

Keyword(s):

Seasonal Variation ◽

Nitrogen Dioxide ◽

Transport Model ◽

Surface Ozone ◽

Oxidative Capacity ◽

Tropospheric Chemistry ◽

Full Description ◽

Ozone Monitoring Instrument ◽

Chemistry Transport Model ◽

Spatial And Seasonal Variation

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Top-Down NOX Emissions of European Cities Based on the Downwind Plume of Modelled and Space-Borne Tropospheric NO2 Columns

Sensors ◽

10.3390/s18092893 ◽

2018 ◽

Vol 18 (9) ◽

pp. 2893 ◽

Cited By ~ 3

Author(s):

Willem W. Verstraeten ◽

Klaas Folkert Boersma ◽

John Douros ◽

Jason E. Williams ◽

Henk Eskes ◽

...

Keyword(s):

Urban Areas ◽

Transport Model ◽

Nox Emissions ◽

Inventory Data ◽

Ozone Monitoring Instrument ◽

Top Down ◽

Chemistry Transport Model ◽

European Cities ◽

Tropospheric No2

Top-down estimates of surface NOX emissions were derived for 23 European cities based on the downwind plume decay of tropospheric nitrogen dioxide (NO2) columns from the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) chemistry transport model (CTM) and from Ozone Monitoring Instrument (OMI) satellite retrievals, averaged for the summertime period (April–September) during 2013. Here we show that the top-down NOX emissions derived from LOTOS-EUROS for European urban areas agree well with the bottom-up NOX emissions from the MACC-III inventory data (R2 = 0.88) driving the CTM demonstrating the potential of this method. OMI top-down NOX emissions over the 23 European cities are generally lower compared with the MACC-III emissions and their correlation is slightly lower (R2 = 0.79). The uncertainty on the derived NO2 lifetimes and NOX emissions are on average ~55% for OMI and ~63% for LOTOS-EUROS data. The downwind NO2 plume method applied on both LOTOS-EUROS and OMI tropospheric NO2 columns allows to estimate NOX emissions from urban areas, demonstrating that this is a useful method for real-time updates of urban NOX emissions with reasonable accuracy.

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Impact of synthetic space-borne NO<sub>2</sub> observations from the Sentinel-4 and Sentinel-5P missions on tropospheric NO<sub>2</sub> analyses

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-12811-2019 ◽

2019 ◽

Vol 19 (19) ◽

pp. 12811-12833 ◽

Cited By ~ 2

Author(s):

Renske Timmermans ◽

Arjo Segers ◽

Lyana Curier ◽

Rachid Abida ◽

Jean-Luc Attié ◽

...

Keyword(s):

Error Estimates ◽

Temporal Resolution ◽

Transport Model ◽

Surface Ozone ◽

Low Earth Orbit ◽

Added Value ◽

High Temporal Resolution ◽

Chemistry Transport Model ◽

European Continent ◽

Global Coverage

Abstract. We present an Observing System Simulation Experiment (OSSE) dedicated to the evaluation of the added value of the Sentinel-4 and Sentinel-5P missions for tropospheric nitrogen dioxide (NO2). Sentinel-4 is a geostationary (GEO) mission covering the European continent, providing observations with high temporal resolution (hourly). Sentinel-5P is a low Earth orbit (LEO) mission providing daily observations with a global coverage. The OSSE experiment has been carefully designed, with separate models for the simulation of observations and for the assimilation experiments and with conservative estimates of the total observation uncertainties. In the experiment we simulate Sentinel-4 and Sentinel-5P tropospheric NO2 columns and surface ozone concentrations at 7 by 7 km resolution over Europe for two 3-month summer and winter periods. The synthetic observations are based on a nature run (NR) from a chemistry transport model (MOCAGE) and error estimates using instrument characteristics. We assimilate the simulated observations into a chemistry transport model (LOTOS-EUROS) independent of the NR to evaluate their impact on modelled NO2 tropospheric columns and surface concentrations. The results are compared to an operational system where only ground-based ozone observations are ingested. Both instruments have an added value to analysed NO2 columns and surface values, reflected in decreased biases and improved correlations. The Sentinel-4 NO2 observations with hourly temporal resolution benefit modelled NO2 analyses throughout the entire day where the daily Sentinel-5P NO2 observations have a slightly lower impact that lasts up to 3–6 h after overpass. The evaluated benefits may be even higher in reality as the applied error estimates were shown to be higher than actual errors in the now operational Sentinel-5P NO2 products. We show that an accurate representation of the NO2 profile is crucial for the benefit of the column observations on surface values. The results support the need for having a combination of GEO and LEO missions for NO2 analyses in view of the complementary benefits of hourly temporal resolution (GEO, Sentinel-4) and global coverage (LEO, Sentinel-5P).

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EnKF and 4D-Var Data Assimilation with a Chemistry Transport Model

10.5194/gmd-2016-95 ◽

2016 ◽

Cited By ~ 1

Author(s):

Sergey Skachko ◽

Richard Menard ◽

Quentin Errera ◽

Yves Christophe ◽

Simon Chabrillat

Keyword(s):

Data Assimilation ◽

Transport Model ◽

Model Error ◽

The Other ◽

Full Description ◽

Observation Error ◽

Tracer Transport ◽

Chemistry Transport Model ◽

Stratospheric Chemistry ◽

Chemical Tracer

Abstract. We compare two optimized chemical data assimilation systems, one based on the ensemble Kalman filter (EnKF) and the other based on four-dimensional variational (4D-Var), using a comprehensive stratospheric chemistry transport model (CTM). The work is an extension of the Belgian Assimilation System for Chemical ObsErvations (BASCOE), initially designed to work with a 4D-Var data assimilation. A strict comparison of both methods in the case of chemical tracer transport was done in a previous study and indicated that both methods provide essentially similar results. In the present work, we assimilate observations of ozone, HCl, HNO3, H2O and N2O from EOS Aura-MLS data into the BASCOE CTM with a full description of stratospheric chemistry. Two new issues related to the use of full chemistry model with EnKF are taken into account. One issue concerns to a large number of error variance parameters that need to be optimized. We estimate an observation error parameter as function of pressure level for each observed species using the Desroziers' method. For comparison reasons, we apply the same estimate procedure in the 4D-Var data assimilation, where we keep both estimates: the background and observation error variances. However in EnKF, the background error covariance is modelled using the full chemistry model and a model error term. We found that it is adequate to have a single model error based on the chemical tracer formulation that is applied for all species. This is an indication that the main source of model error in chemical transport model is due to the transport. The second issue in EnKF with comprehensive atmospheric chemistry models is the sampling errors between species. When species are weakly chemically related, cross-species sampling noise errors occur at the same location. These errors need to be filtered out, in addition to a localization based on distance. The performance of two data assimilation methods was assessed through an eight-month long assimilation of limb sounding observations from EOS Aura-MLS. The paper discusses the differences in results and their relation to stratospheric chemical processes. Generally speaking, EnKF and 4D-Var provide results of comparable quality but differ substantially in presence of model error or observation biases. If the erroneous chemical modelling is associated with not too small chemical life-times, then EnKF performs better, while 4D-Var develops spurious increments in the chemically related species. If, on the other hand, the observation biases are significant, then 4D-Var is more robust and is able to reject erroneous observations, while EnKF does not.

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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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Ozone pollution during the COVID-19 lockdown in the spring 2020 over Europe analysed from satellite observations, in situ measurements and models

10.5194/acp-2021-785 ◽

2021 ◽

Author(s):

Juan Cuesta ◽

Lorenzo Costantino ◽

Matthias Beekmann ◽

Guillaume Siour ◽

Laurent Menut ◽

...

Keyword(s):

Large Scale ◽

Transport Model ◽

Surface Ozone ◽

In Situ Measurements ◽

Satellite Observations ◽

Emission Inventories ◽

Ozone Pollution ◽

Chemistry Transport Model ◽

Near Surface

Abstract. We present a comprehensive study integrating satellite observations of ozone pollution, in situ measurements and chemistry transport model simulations for quantifying the role of anthropogenic emission reductions during the COVID-19 lockdown in spring 2020 over Europe. Satellite observations are derived from the IASI+GOME2 multispectral synergism, which provides particularly enhanced sensitivity to near-surface ozone pollution. These observations are first analysed in terms of differences between the average on 1–15 April 2020, when the strictest lockdown restrictions took place, and the same period in 2019. They show clear enhancements of near-surface ozone in Central Europe and Northern Italy, and some other hotspots, which are typically characterized by VOC-limited chemical regimes. An overall reduction of ozone is observed elsewhere, where ozone chemistry is limited by the abundance of NOx. The spatial distribution of positive and negative ozone concentration anomalies observed from space is in relatively good quantitative agreement with surface in situ measurements over the continent (a correlation coefficient of 0.55, a root-mean-squared difference of 11 ppb and the same standard deviation and range of variability). An average bias of ∼8 ppb between the two observational datasets is remarked, which can partly be explained by the fact the satellite approach retrieves partial columns of ozone with a peak sensitivity above the surface (near 2 km of altitude). For assessing the impact of the reduction of anthropogenic emissions during the lockdown, we adjust the satellite and in situ surface observations for withdrawing the influence of meteorological conditions in 2020 and 2019. This adjustment is derived from the chemistry transport model simulations using the meteorological fields of each year and identical emission inventories. This observational estimate of the influence of lockdown emission reduction is consistent for both datasets. They both show lockdown-associated ozone enhancements in hotspots over Central Europe and Northern Italy, with a reduced amplitude with respect to the total changes observed between the two years, and an overall reduction elsewhere over Europe and the ocean. Satellite observations additionally highlight the ozone anomalies in the regions remote from in situ sensors, an enhancement over the Mediterranean likely associated with maritime traffic emissions and a marked large-scale reduction of ozone elsewhere over ocean (particularly over the North Sea), in consistency with previous assessments done with ozonesondes measurements in the free troposphere. These observational assessments are compared with model-only estimations, using the CHIMERE chemistry transport model. For analysing the uncertainty of the model estimates, we perform two sets of simulations with different setups, differing in the emission inventories, their modifications to account for changes in anthropogenic activities during the lockdown and the meteorological fields. Whereas a general qualitative consistency of positive and negative ozone anomalies is remarked between all model and observational estimates, significant changes are seen in their amplitudes. Models underestimate the range of variability of the ozone changes by at least a factor 2 with respect to the two observational data sets, both for enhancements and decreases of ozone, while the large-scale ozone decrease is not simulated. With one of the setups, the model simulates ozone enhancements a factor 3 to 6 smaller than with the other configuration. This is partly linked to the emission inventories of ozone precursors (at least a 30 % difference), but mainly to differences in vertical mixing of atmospheric constituents depending on the choice of the meteorological model.

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Towards a representation of halogen chemistry within volcanic plumes in a chemistry transport model

Geoscientific Model Development Discussions ◽

10.5194/gmdd-7-2581-2014 ◽

2014 ◽

Vol 7 (2) ◽

pp. 2581-2650 ◽

Cited By ~ 4

Author(s):

L. Grellier ◽

V. Marécal ◽

B. Josse ◽

P. D. Hamer ◽

T. J. Roberts ◽

...

Keyword(s):

Transport Model ◽

Computational Cost ◽

Ambient Air ◽

Heterogeneous Reactions ◽

Tropospheric Chemistry ◽

Volcanic Plume ◽

Large Set ◽

Chemistry Transport Model ◽

Volcanic Plumes ◽

The Impact

Abstract. Volcanoes are a known source of halogens to the atmosphere. HBr volcanic emissions lead rapidly to the formation of BrO within volcanic plumes as shown by recent work based on observations and models. BrO, having a longer residence time in the atmosphere than HBr, is expected to have a significant impact on tropospheric chemistry, at least at the local and regional scales. The objective of this paper is to prepare a framework that will allow 3-D modelling of volcanic halogen emissions in order to determine their fate within the volcanic plume and then in the atmosphere at the regional and global scales. This work is based on a 1-D configuration of the chemistry transport model MOCAGE whose low computational cost allows us to perform a large set of sensitivity studies. This paper studies the Etna eruption on the 10 May 2008 that took place just before night time. Adaptations are made to MOCAGE to be able to produce the chemistry occurring within the volcanic plume. A simple sub-grid scale parameterization of the volcanic plume is implemented and tested. The use of this parameterization in a 0.5° × 0.5° configuration (typical regional resolution) has an influence on the partitioning between the various bromine compounds both during the eruption period and also during the night period immediately afterwards. During the day after the eruption, simulations both with and without parameterizations give very similar results that are consistent with the tropospheric column of BrO and SO2 in the volcanic plume derived from GOME-2 observations. Tests have been performed to evaluate the sensitivity of the results to the mixing between ambient air and the magmatic air at very high temperature at the crater vent that modifies the composition of the emission, and in particular the sulphate aerosol content that is key compound in the BrO production. Simulations show that the plume chemistry is not very sensitive to the assumptions used for the mixing parameter (relative quantity of ambient air mixed with magmatic air in the mixture) that is not well known. This is because there is no large change in the compounds limiting/favouring the BrO production in the plume. The impact of the model grid resolution is also tested in view of future 3-D-simulations at the global scale. A dilution of the emitted gases and aerosols is observed when using the typical global resolution (2°) as compared to a typical regional resolution (0.5°), as expected. Taking this into account, the results of the 2° resolution simulations are consistent with the GOME-2 observations. In general the simulations at 2° resolution are less efficient at producing BrO after the emission both with and without the subgrid-scale parameterization. The differences are mainly due to an interaction between concentration effects than stem from using a reduced volume in the 0.5° resolution combined with second order rate kinetics. The last series of tests were on the mean radius assumed for the sulphate aerosols that indirectly impacts the production of BrO by heterogeneous reactions. The simulations show that the BrO production is sensitive to this parameter with a stronger production when smaller aerosols are assumed. These results will be used to guide the implementation of volcanic halogen emissions in the 3-D configuration of MOCAGE.

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Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990–2013

10.5194/acp-2017-338 ◽

2017 ◽

Author(s):

Camilla Andersson ◽

Heléne Alpfjord ◽

Lennart Robertson ◽

Per Erik Karlsson ◽

Magnuz Engardt

Keyword(s):

Transport Model ◽

Linear Trend ◽

Surface Ozone ◽

Vegetation Indices ◽

High Sensitivity ◽

Anthropogenic Emissions ◽

Data Sets ◽

Chemistry Transport Model ◽

Near Surface ◽

Surface O3

Abstract. We have constructed two data sets of hourly resolution reanalyzed near-surface ozone (O3) concentrations for the period 1990–2013 for Sweden. Long-term simulations from a chemistry-transport model (CTM) covering Europe were combined with hourly ozone concentration observations at Swedish and Norwegian background measurement sites using data assimilation. The reanalysis data sets show improved performance than the original CTM when compared to independent observations. In one of the reanalyzes we included all available hourly near-surface O3 observations, whilst in the other we carefully selected time-consistent observations in order to avoid introducing artificial trends. Based on the second reanalysis we investigated statistical aspects of the near-surface O3 concentration, focusing on the linear trend over the 24 year period. We show that high near-surface O3 concentrations are decreasing and low O3 concentrations are increasing, which is mirrored by observed improvement of many health and vegetation indices (apart from those with a low threshold). Using the chemistry-transport model we also conducted sensitivity simulations to quantify the causes of the observed change, focusing on three processes: change in hemispheric background, meteorology and anthropogenic emissions (Swedish and other European). The rising low concentrations of near-surface O3 in Sweden are caused by a combination of all three processes, whilst the decrease in the highest O3 concentrations is caused by O3 precursor emissions reductions. While studying the relative impact of anthropogenic emissions changes, we identified systematic differences in the modelled trend compared to observations that must be caused by incorrect trends in the utilised emissions inventory or by too high sensitivity of our model to emissions changes.

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-9183-2007 ◽

2007 ◽

Vol 7 (3) ◽

pp. 9183-9202 ◽

Cited By ~ 2

Author(s):

G. Dufour ◽

S. Szopa ◽

D. A. Hauglustaine ◽

C. D. Boone ◽

C. P. Rinsland ◽

...

Keyword(s):

Fourier Transform ◽

Transport Model ◽

State Of The Art ◽

Tropospheric Chemistry ◽

Biogenic Emissions ◽

Fourier Transform Spectrometer ◽

Satellite Measurements ◽

Chemistry Transport Model ◽

Organic Species ◽

Global Space

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Effects of stratospheric ozone recovery on tropospheric chemistry and air quality

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-21427-2013 ◽

2013 ◽

Vol 13 (8) ◽

pp. 21427-21453

Author(s):

H. Zhang ◽

S. Wu ◽

Y. Wang

Keyword(s):

Air Quality ◽

Transport Model ◽

Stratospheric Ozone ◽

Surface Ozone ◽

Montreal Protocol ◽

Tropospheric Chemistry ◽

Chemical Transport Model ◽

Photolysis Rates ◽

Global Chemical Transport Model ◽

Ozone Depleting Substances

Abstract. The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increases by 0.78%. The perturbations to tropospheirc ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 5% for some regions.

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