scholarly journals The On-Line Integrated Mesoscale Chemistry Model BOLCHEM

Atmosphere ◽  
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.

scholarly journals Bolchem: an On-Line Coupled Mesoscale Chemistry Model

2019 ◽  
Author(s):  
Rita Cesari ◽  
Alberto Maurizi ◽  
Massimo D'Isidoro ◽  
Tony Christian Landi ◽  
Mihaela Mircea ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Transport Model ◽  
Operator Splitting ◽  
Splitting Method ◽  
Chemistry Transport Model ◽  
Continental Scale ◽  
Operator Splitting Method ◽  
On Line ◽  
Removal Processes ◽  
Wet Removal

Abstract. 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 integretation step, by means of operator splitting method. The paper describes the model and shows the model performances at continental scale for oneyear run (December 2009–November 2010). The results show that BOLCHEM reproduces both O3 and PM10 at surface. For O3, we found the best agreement in the summer, with a correlation coefficient R of 0.7 and mean bias of 4.0. On the contrary, PM10 is better reproduced in the winter, with a correlation coefficient R of 0.6 and the mean bias MB of 6.7.

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

2011 ◽  
Vol 4 (4) ◽  
pp. 1077-1102 ◽  
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.

scholarly journals Equilibrium of sinks and sources of sulphate over Europe: comparison between a six-year simulation and EMEP observations

2009 ◽  
Vol 9 (13) ◽  
pp. 4505-4519 ◽  
Author(s):  
M. Ménégoz ◽  
D. Salas y Melia ◽  
M. Legrand ◽  
H. Teyssèdre ◽  
M. Michou ◽  
...  
Keyword(s):  
Transport Model ◽  
Weather Conditions ◽  
General Tendency ◽  
Chemistry Transport Model ◽  
Annual Variations ◽  
Sulphur Cycle ◽  
Sulphate Aerosols ◽  
Chemical Scheme ◽  
One Year ◽  
Year 2000

Abstract. Sulphate distributions were simulated with a global chemistry transport model. A chemical scheme describing the sulphur cycle and the parameterisations of the main sinks for sulphate aerosols were included in the model. A six-year simulation was conducted from the years 2000 to 2005, driven by the ECMWF operational analyses. Emissions come from an inventory representative of the year 2000. This paper focuses on the analysis of the sulphate sinks and sources over Europe for the entire period of simulation. The Sulphate burden shows a marked annual cycle, which is the result of the annual variations of the aqueous and gaseous chemistry. Regionally, the monthly mean aerosol burden can vary by a factor of 2 from one year to another, because of different weather conditions, driving chemistry, transport and wet deposition of sulphate aerosols. Sulphate ground concentrations, scavenging fluxes and precipitation modelled were compared with observations. The model represents quite well sulphate fields over Europe, but has a general tendency to overestimate sulphate ground concentrations, in particular over Northern Europe. We assume that it is linked to the representation of the scavenging fluxes, which are underestimated. We suggest that uncertainties in modelled precipitation explain only partially the underestimation of the scavenging fluxes in the model.

scholarly journals Impact of the vertical emission profiles on background gas-phase pollution simulated from the EMEP emissions over Europe

2013 ◽  
Vol 13 (12) ◽  
pp. 5987-5998 ◽  
Author(s):  
S. Mailler ◽  
D. Khvorostyanov ◽  
L. Menut
Keyword(s):  
Air Quality ◽  
Gas Phase ◽  
Recent Literature ◽  
Transport Model ◽  
Anthropogenic Emissions ◽  
Vertical Profiles ◽  
Chemistry Transport Model ◽  
Vertical Injection ◽  
One Year ◽  
Background Gas

Abstract. Five one-year air quality simulations over a domain covering Europe have been performed using the CHIMERE chemistry transport model and the EMEP emission dataset for Europe. These five simulations differ only by the representation of the effective emission heights for anthropogenic emissions: one has been run using the EMEP standard recommendations, three others with vertical injection profiles derived from the EMEP recommendations but multiplying the injection height by 0.75, 0.50 and 0.25, respectively, while the last one uses vertical profiles derived from the recent literature. It is shown that using injection heights lower than the EMEP recommendations leads to significantly improved simulation of background SO2, NO2 and O3 concentrations when compared to the Airbase station measurements.

scholarly journals Impact of the vertical emission profiles on ground-level gas-phase pollution simulated from the EMEP emissions over Europe

2013 ◽  
Vol 13 (2) ◽  
pp. 3663-3693
Author(s):  
S. Mailler ◽  
D. Khvorostyanov ◽  
L. Menut
Keyword(s):  
Air Quality ◽  
Gas Phase ◽  
Recent Literature ◽  
Transport Model ◽  
Ground Level ◽  
Anthropogenic Emissions ◽  
Vertical Profiles ◽  
Chemistry Transport Model ◽  
Vertical Injection ◽  
One Year

Abstract. Five one-year air quality simulations over a domain covering Europe have been performed using the CHIMERE chemistry transport model and the EMEP emission dataset for Europe. These five simulations differ only by the representation of the effective emission heights for anthropogenic emissions: one has been run using the EMEP standard recommandations, three others with vertical injection profiles derived from the EMEP recommandations but multiplying the injection height by respectively 0.75, 0.50 and 0.25, while the last one uses vertical profiles derived from the recent literature. It is shown that using injection heights lower than the EMEP recommandations leads to significantly improved simulation of SO2, NO2 and O3 concentrations when compared to the Airbase station measurements.

scholarly journals Simulating CH<sub>4</sub> and CO<sub>2</sub> over South and East Asia using the zoomed chemistry transport model LMDzINCA

2017 ◽  
Author(s):  
Xin Lin ◽  
Philippe Ciais ◽  
Philippe Bousquet ◽  
Michel Ramonet ◽  
Yi Yin ◽  
...  
Keyword(s):  
East Asia ◽  
Transport Model ◽  
Model Performance ◽  
Horizontal Resolution ◽  
Surface Fluxes ◽  
Vertical Resolution ◽  
Monitoring Networks ◽  
Atmospheric Measurements ◽  
Monsoon Period ◽  
Chemistry Transport Model

Abstract. The increasing availability of atmospheric measurements of greenhouse gases (GHGs) from surface stations can improve the retrieval of their fluxes at higher spatial and temporal resolutions by inversions, provided that chemistry transport models are able to properly represent the variability of concentrations observed at different stations. South and East Asia (SEA) is a region with large and very uncertain emissions of carbon dioxide (CO2) and methane (CH4), the most potent anthropogenic GHGs. Monitoring networks have expanded greatly during the past decade in this region, which should contribute to reducing uncertainties in estimates of regional GHG budgets. In this study, we simulate concentrations of CH4 and CO2 using a zoomed version of the global chemistry transport model LMDzINCA during the period 2006–2013. The zoomed version has a fine horizontal resolution of ~ 0.66° in longitude and ~0.51° in latitude over SEA and a coarser resolution elsewhere. The concentrations of CH4 and CO2 simulated from the zoomed model (abbreviated as ‘ZASIA’) are compared to those from the same model but with a uniform regular grid of 2.50° in longitude and 1.27° in latitude (abbreviated as ‘REG’), both having the same vertical 19 sigma pressure levels and prescribed with the same biogenic and anthropogenic fluxes. Model performance is evaluated for annual gradients between sites, seasonal, synoptic and diurnal variations, against a new dataset including 30 surface stations over SEA and adjacent regions. Our results show that, when prescribed with identical surface fluxes, compared to REG, the ZASIA version moderately improves the representation of CH4 mean annual gradients between stations as well as the seasonal and synoptic variations of this trace gas within the zoomed region. This moderate improvement probably results from reduction of representation errors and a better description of the CH4 concentration gradients related to the skewed spatial distribution of surface CH4 emissions, suggesting that the zoom transport model will be better suited for inversions of CH4 fluxes in SEA. With the relatively coarse vertical resolution and low-frequency (monthly) prescribed fluxes, the model generally does not capture the diurnal cycle of CH4 at most stations even with its zoomed configuration, emphasizing the need to increase the vertical resolution, and to improve parameterizations of turbulent diffusion in the planetary boundary layer and deep convection during the monsoon period. The model performance for CH4 is better than that for CO2 at any temporal scale, likely due to inaccuracies in the CO2 fluxes prescribed in this study.

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

2011 ◽  
Vol 4 (4) ◽  
pp. 873-900 ◽  
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

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.

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

2011 ◽  
Vol 4 (2) ◽  
pp. 1129-1183 ◽  
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

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.

scholarly journals Development of a custom OMI NO<sub>2</sub> data product for evaluating biases in a regional chemistry transport model

2015 ◽  
Vol 15 (10) ◽  
pp. 5627-5644 ◽  
Author(s):  
G. Kuhlmann ◽  
Y. F. Lam ◽  
H. M. Cheung ◽  
A. Hartl ◽  
J. C. H. Fung ◽  
...  
Keyword(s):  
Hong Kong ◽  
Air Quality ◽  
High Resolution ◽  
Correlation Coefficient ◽  
Spatial Resolution ◽  
Transport Model ◽  
Satellite Observations ◽  
Surface Reflectance ◽  
Data Set ◽  
Chemistry Transport Model

Abstract. In this paper, we present the custom Hong Kong NO2 retrieval (HKOMI) for the Ozone Monitoring Instrument (OMI) on board the Aura satellite which was used to evaluate a high-resolution chemistry transport model (CTM) (3 km × 3 km spatial resolution). The atmospheric chemistry transport was modelled in the Pearl River Delta (PRD) region in southern China by the Models-3 Community Multiscale Air Quality (CMAQ) modelling system from October 2006 to January 2007. In the HKOMI NO2 retrieval, tropospheric air mass factors (AMFs) were recalculated using high-resolution ancillary parameters of surface reflectance, a priori NO2 and aerosol profiles, of which the latter two were taken from the CMAQ simulation. We tested the influence of the ancillary parameters on the data product using four different aerosol parametrizations. Ground-level measurements by the PRD Regional Air Quality Monitoring (RAQM) network were used as additional independent measurements. The HKOMI retrieval increases estimated tropospheric NO2 vertical column densities (VCD) by (+31 ± 38)%, when compared to NASA's standard product (OMNO2-SP), and improves the normalized mean bias (NMB) between satellite and ground observations by 26 percentage points from −41 to −15%. The individual influences of the parameters are (+11.4 ± 13.4)% for NO2 profiles, (+11.0 ± 20.9)% for surface reflectance and (+6.0 ± 8.4)% for the best aerosol parametrization. The correlation coefficient r is low between ground and satellite observations (r = 0.35). The low r and the remaining NMB can be explained by the low model performance and the expected differences when comparing point measurements with area-averaged satellite observations. The correlation between CMAQ and the RAQM network is low (r ≈ 0.3) and the model underestimates the NO2 concentrations in the northwestern model domain (Foshan and Guangzhou). We compared the CMAQ NO2 time series of the two main plumes with our best OMI NO2 data set (HKOMI-4). The model overestimates the NO2 VCDs by about 15% in Hong Kong and Shenzhen, while the correlation coefficient is satisfactory (r = 0.56). In Foshan and Guangzhou, the correlation is low (r = 0.37) and the model underestimates the VCDs strongly (NMB = −40%). In addition, we estimated that the OMI VCDs are also underestimated by about 10 to 20% in Foshan and Guangzhou because of the influence of the model parameters on the AMFs. In this study, we demonstrate that the HKOMI NO2 retrieval reduces the bias of the satellite observations and how the data set can be used to study the magnitude of NO2 concentrations in a regional model at high spatial resolution of 3 × 3 km2. The low bias was achieved with recalculated AMFs using updated surface reflectance, aerosol profiles and NO2 profiles. Since unbiased concentrations are important, for example, in air pollution studies, the results of this paper can be very helpful in future model evaluation studies.

scholarly journals Evaluation of a regional chemistry transport model using a newly developed regional OMI NO<sub>2</sub> retrieval

2014 ◽  
Vol 14 (22) ◽  
pp. 31039-31090
Author(s):  
G. Kuhlmann ◽  
Y. F. Lam ◽  
H. M. Cheung ◽  
A. Hartl ◽  
J. C. H. Fung ◽  
...  
Keyword(s):  
Hong Kong ◽  
Air Quality ◽  
High Resolution ◽  
Correlation Coefficient ◽  
Atmospheric Chemistry ◽  
Transport Model ◽  
Southern China ◽  
Model Parameters ◽  
Surface Reflectance ◽  
Chemistry Transport Model

Abstract. In this paper, we evaluate a high-resolution chemistry transport model (CTM) (3 km x 3 km spatial resolution) with the new Hong Kong (HK) NO2 retrieval developed for the Ozone Monitoring Instrument (OMI) on-board the Aura satellite. The three-dimensional atmospheric chemistry was modelled in the Pearl River Delta (PRD) region in southern China by the Models-3 Community Multiscale Air Quality (CMAQ) modelling system from October 2006 to January 2007. In the HK NO2 retrieval, tropospheric air mass factors (AMF) were recalculated using high-resolution ancillary parameters of surface reflectance, NO2 profile shapes and aerosol profiles of which the latter two were taken from the CMAQ simulation. We also tested four different aerosol parametrizations. Ground level measurements by the PRD Regional Air Quality Monitoring (RAQM) network were used as additional independent measurements. The HK NO2 retrieval increases the NO2 vertical column densities (VCD) by (+31 ± 38) %, when compared to NASA's standard product (SP2), and reduces the mean bias (MB) between satellite and ground measurements by 26 percentage points from −41 to −15 %. The correlation coefficient r is low for both satellite datasets (r = 0.35) due to the high spatial variability of NO2 concentrations. The correlation between CMAQ and the RAQM network is low (r &amp;approx; 0.3) and the model underestimates the NO2 concentrations in the north-western model domain (Foshan and Guangzhou). We compared the CMAQ NO2 time series of the two main plumes with our regional OMI NO2 product. The model overestimates the NO2 VCDs by about 15 % in Hong Kong and Shenzhen, while the correlation coefficient is satisfactory (r = 0.56). In Foshan and Guangzhou, the correlation is low (r = 0.37) and the model underestimates the VCDs strongly (MB = −40 %). In addition, we estimated that the OMI VCDs are also underestimated by about 10 to 20 % in Foshan and Guangzhou because of the influence of the model parameters on the AMF. In this study, we demonstrate that the HK OMI NO2 retrieval reduces the bias of the satellite measurements and thus the dataset can be used to study the magnitude of NO2 concentrations in a regional model. The low bias can be achieved if AMFs are recalculated with more accurate surface reflectance, aerosol profiles and NO2 profiles; only NO2 profiles have been replaced in earlier studies. Since unbiased concentrations are important, for example, in air pollution studies, the results of this paper can be very helpful in future model evaluation studies.

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