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August 2008 - August 2009
November 2010 - present
April 2003 - November 2010
Education
April 2003 - June 2006
Publications
Publications (185)
Human activities have profoundly altered natural vegetation, primarily by converting pristine land for agriculture and grazing. Land cover change (LCC) influences the Earth system through modifications of surface albedo, roughness length, evapotranspiration, and atmospheric composition. This work investigates how LCC-driven changes in BVOC fluxes,...
For balloon-borne detection of aerosols and cloud droplets (diameter 0.4 < Dp< 40 µm), a passive-flow Universal Cloud and Aerosol Sounding System (UCASS) was used, whose sample flow rate is conventionally derived from GPS-based balloon’s ascent rates. Improvements are achieved by implementing thermal flow sensors (TFS) 94 mm downstream of the UCASS...
Convective transport leads to a rapid vertical redistribution of tracers. This has a major influence on the composition of the upper troposphere, a highly climate sensitive region. It is not yet clear how the convective transport is affected by climate change. In this study, we applied a new tool, the so-called convective exchange matrix, in histor...
This sequence of papers examines spatio-temporal patterns of convective cloud activity and organisation. In response to the limitations of current remote sensing sensors, our analysis employs a machine learning (ML)-based contiguous 3D extrapolation of 2D satellite data. In Part 2, we investigate spatio-temporal patterns of convective organisation...
In this two-part sequence of papers, we investigate spatio-temporal patterns of convective cloud activity and organisation. The analysis employs a machine learning (ML)-based contiguous 3D extrapolation of satellite data from multiple sensors to simultaneously follow horizontal and vertical cloud development. Our study covers West Africa, a hotspot...
Benzo(a)pyrene (BaP) is a ubiquitous and hazardous air pollutant that increases the risk of lung cancer. Heterogeneous oxidation by ozone limits the atmospheric concentrations and long-range transport potential of BaP, but the actual oxidation rates and chemical lifetimes of BaP under varying atmospheric conditions are not yet well constrained. In...
Benzo(a)pyrene (BaP) is a ubiquitous and hazardous air pollutant that increases the risk of lung cancer. Heterogeneous oxidation by ozone limits the atmospheric concentrations and long-range transport potential of BaP, but the actual oxidation rates and chemical lifetimes of BaP under varying atmospheric conditions are not yet well constrained. In...
Biogenic volatile organic compounds (BVOCs) are emitted in large quantities from the terrestrial biosphere and play a significant role in atmospheric gaseous and aerosol compositions. Secondary organic aerosols (SOAs) resulting from BVOC oxidation affect the radiation budget both directly, through the scattering and absorption of sunlight, and indi...
The chemical composition of the upper troposphere/lower stratosphere (UTLS) plays an important role for the climate by affecting the radiation budget. Small-scale diabatic mixing like turbulence has a significant impact on the distribution of tracers which further affect the energy budget via their radiative impact. Current models usually have a hi...
We present a methodological study to document the operation of a new submodel for tracer emissions from Explosive Volcanic ERuptions (EVER v1.1), developed within the Modular Earth Submodel System (MESSy, version 2.55.1). EVER calculates additional tendencies of gaseous and aerosol tracers based on volcanic emission source parameters, aligned to sp...
We present the coupling of the Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg version 4 (JSBACHv4) to the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. With JSBACH, the soil water bucket model in EMAC is replaced by a diffusive hydrological transport model for soil water that includes water storage and infiltration in five soil layers,...
Biogenic volatile organic compounds (BVOC) are emitted in large quantities from the terrestrial biosphere and play a significant role in atmospheric gaseous and aerosol composition. Such emissions account for 90 % of the total global volatile organic compound (VOC) emissions and exert a significant influence on the atmosphere’s oxidation capacity....
Upper-tropospheric deep convective outflows during an event on 10–11 June 2019 over central Europe are analysed in ensembles of the operational Icosahedral Nonhydrostatic (ICON) numerical weather prediction model. Both a parameterised and an explicit representation of deep convective systems is studied. Near-linear response of deep convective outfl...
Aqueous-phase chemical processes in clouds, fog, and deliquescent aerosols are known to alter atmospheric composition and acidity significantly. Traditionally, global and regional models predict aerosol composition by relying on thermodynamic equilibrium models and neglect non-equilibrium processes. Here, we present the AERosol CHEMistry (GMXe–AERC...
This study explores the differences in performance and results by various versions of the ISORROPIA thermodynamic module implemented within the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. Three different versions of the module were used, ISORROPIA II v1, ISORROPIA II v2.3, and ISORROPIA-lite. First, ISORROPIA II v2.3 replaced ISORROPIA II v1 in...
Satellite instruments provide high-temporal-resolution data on a global scale, but extracting 3D information from current instruments remains a challenge. Most observational data are two-dimensional (2D), offering either cloud top information or vertical profiles. We trained a neural network (Res-UNet) to merge high-resolution satellite images from...
We present the coupling of the Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg (JSBACH) version four to the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. With JSBACH, the soil water bucket model in EMAC is replaced by a diffusive hydrological transport model for soil water that includes water storage and infiltration in five soil layers,...
Aqueous-phase chemical processes in clouds, fog, and deliquescent aerosols are known to alter atmospheric composition and acidity significantly. Traditionally, global and regional models predict aerosol composition by relying on thermodynamic equilibrium models and neglect non-equilibrium processes. Here, we present the AERosol CHEMistry (GMXe–AERC...
Emissions of biogenic volatile organic compounds (BVOCs) from the terrestrial biosphere play a significant role in major atmospheric processes. BVOCs are highly reactive compounds that influence the atmosphere's oxidation capacity and also serve as precursors for the formation of aerosols that influence global radiation budgets. Emissions depend on...
This study explores the differences in performance and results by various versions of the ISORROPIA thermodynamic module implemented within the global atmospheric chemistry model EMAC. Three different versions of the module were used, ISORROPIA II v1, ISORROPIA II v2.3, and ISORROPIA-lite. First, ISORROPIA II v2.3 replaced ISORROPIA II v1 in EMAC t...
Satellite instruments provide spatially extended data with a high temporal resolution on almost global scales. However, nowadays, it is still a challenge to extract fully three-dimensional data from the current generation of satellite instruments, which either provide horizontal patterns or vertical profiles along the orbit track. Following this, w...
We present a novel method to identify and locate weather fronts at various pressure levels to create a three dimensional structure using weather data located at the North Atlantic. It provides statistical evaluations regarding the slope and weather phenomena correlated to the identified three dimensional structure. Our approach is based on a deep n...
Upper-tropospheric outflow is analysed in cloud-resolving large-eddy simulations. Thereby, the role of convective organization, latent heating, and other factors in upper-tropospheric divergent-outflow variability from deep convection is diagnosed using a set of more than 80 large-eddy simulations because the outflows are thought to be an important...
Isoprene and monoterpene emissions from the terrestrial biosphere play a significant role in major atmospheric processes. Emissions depend on the vegetation's response to atmospheric conditions (primarily temperature and light), as well as other stresses e.g. from droughts and herbivory. It has been well documented that biogenic volatile organic co...
Upper-tropospheric deep convective outflows during an event on 10th–11th of June 2019 over Central Europe are analysed from simulation output of the operational numerical weather prediction model ICON. Both, a parameterised and an explicit representation of deep convective systems are studied. Near-linear response of deep convective outflow strengt...
Earth system models (ESMs) integrate previously separate models of the ocean, atmosphere and vegetation into one comprehensive modelling system enabling the investigation of interactions between different components of the Earth system. Global isoprene and monoterpene emissions from terrestrial vegetation, which represent the most important source...
A chain of processes is identified that regulates much of the spread in an ensemble of squall lines in large eddy simulations with tight initial conditions. Patterns of gravity wave propagation de-correlate and restructure the initial condition spread until a second phase of convective initiation is taking place, i.e. after 30 min of simulation tim...
We employ the ECHAM5/MESSy2 atmospheric chemistry general circulation model (EMAC) that incorporates calculations of gas-phase and heterogeneous chemistry coupled with the ozone cycle and aerosol formation, transport, and microphysics to calculate the 1991 Pinatubo volcanic cloud. We considered simultaneous injections of SO2, volcanic ash, and wate...
Urbanization requires the replacement of natural land into impervious surfaces, which in turn leads to surface sealing and a loss of natural soil functions. Next to a modification of the surface hydrological properties, warming of concrete materials arouses a respective warming of the air aloft. This study analyses the impact of increased sensible...
Upper tropospheric outflow is analysed in cloud resolving large eddy simulations. Thereby, the role of convective organisation, latent heating and other factors in upper tropospheric divergent outflow variability from deep convection is diagnosed using a set of about 100 large eddy simulations, because the outflows are thought to be an important fe...
Earth system models (ESMs) integrate previously separate models of the ocean, atmosphere and vegetation in one comprehensive modelling system enabling the investigation of interactions between different components of the Earth system. Global isoprene and monoterpene emissions from terrestrial vegetation, which represents the most important source o...
Squall lines represent an organized form of atmospheric convection that link processes occurring at the small end of the mesoscale and processes ocurring at the large end of the mesoscale. This study analyses the initial condition sensitivity of idealized squall lines in an LES ensemble. The ensemble spread of the squall lines is evaluated using pa...
We employ the atmospheric chemistry general circulation model (EMAC) with gas phase, heterogeneous chemistry, and detailed aerosol microphysics to simulate the 1991 Pinatubo volcanic cloud. We explicitly account for the interaction of simultaneously injected SO2, volcanic ash, and water vapor and conducted multiple ensemble simulations with differe...
An updated and expanded representation of organics in the chemistry general circulation model EMAC (ECHAM5/MESSy for Atmospheric Chemistry) has been evaluated. First, the comprehensive Mainz Organic Mechanism (MOM) in the submodel MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) was activated with explicit degradation of organ...
An updated and expanded representation of organics in the chemistry general circulation model EMAC (ECHAM5/MESSy for Atmospheric Chemistry) has been evaluated. First, the comprehensive Mainz Organic Mechanism (MOM) in the submodel MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) was activated with explicit degradation of organ...
From 27 July to 10 August 2017, the airborne StratoClim mission took place in Kathmandu, Nepal, where eight mission flights were conducted with the M-55 Geophysica up to altitudes of 20 km. New particle formation (NPF) was identified by the abundant presence of nucleation-mode aerosols, with particle diameters dp smaller than 15 nm, which were in-s...
It has been long understood that land cover change from natural to impervious modifies the surface energy balance and hence the dynamical properties of the overlying atmosphere. The urban heat island is manifested in the formation of an urban boundary layer with distinct thermodynamic features that in turn govern transport processes of air pollutan...
We present high spatial resolution (up to 2.2×2.2 km2) simulations focussed over south-west Germany using the online coupled regional atmospheric chemistry model system MECO(n) (MESSy-fied ECHAM and COSMO models nested n times). Numerical simulation of nitrogen dioxide (NO2) surface volume mixing ratios (VMRs) are compared to in situ measurements f...
Microphysical processes in cold clouds which act as sources or sinks of hydrometeors below 0 ∘C control the ice crystal number concentrations (ICNCs) and in turn the cloud radiative effects. Estimating the relative importance of the cold cloud microphysical process rates is of fundamental importance to underpin the development of cloud parameteriza...
From 27 July to 10 August 2017 the airborne StratoClim mission took place in Kathmandu, Nepal where eight mission flights were conducted with the M-55 Geophysica up to altitudes of 20 km. New Particle Formation (NPF) was identified by the abundant presence of ultrafine aerosols, with particle diameters dp smaller than 15 nm, which were in-situ dete...
As efforts to recognise the Anthropocene as a new epoch of geological time are mounting, the controversial debate about the time of its beginning continues. Here, we suggest the term Palaeoanthropocene for the period between the first, barely recognizable, anthropogenic environmental changes and the industrial revolution when anthropogenically indu...
The sensitivity of upper tropospheric and lower stratospheric convective outflows and related divergence fields is analysed using an ensemble of cloud resolving model (CM1) simulations in LES-mode including various physically manipulated simulations for three different convective systems initialized with an idealized trigger. The main goal of this...
Ozone profile measurements collected at L'Aquila (Italy, 42.4° N) during seventeen years of radio-sounding (2000–2016) are presented here, with an analysis of derived trends. Model results from the SPARC-CCMI exercise are used in parallel to highlight the physical and chemical mechanisms regulating mid-latitude ozone trends. The statistically signi...
A new module has been implemented in the fifth generation of the ECMWF/Hamburg (ECHAM5)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model that simulates cloud-related processes on a much smaller grid. This so-called superparameterisation acts as a replacement for the convection parameterisation and large-scale cloud scheme. T...
Abstract. Microphysical processes in cold clouds which act as sources or sinks of hydrometeors below 0 °C control the ice crystal number concentrations (ICNCs) and in turn the cloud radiative effects. Estimating the relative importance of the cold cloud microphysical process rates is of fundamental importance to underpin the development of cloud pa...
Central to the development of Earth system models (ESMs) has been the coupling of previously separate model types, such as ocean, atmospheric, and vegetation models, to address interactive feedbacks between the system components. A modelling framework which combines a detailed representation of these components, including vegetation and other land...
The hydroxyl radical (OH) plays critical roles within the troposphere, such as determining the lifetime of methane (CH4), yet is challenging to model due to its fast cycling and dependence on a multitude of sources and sinks. As a result, the reasons for variations in OH and the resulting methane lifetime (τCH4), both between models and in time, ar...
Enhanced aerosol abundance in the upper troposphere and lower stratosphere (UTLS) associated with the Asian summer monsoon (ASM) is referred to as the Asian Tropopause Aerosol Layer (ATAL). The chemical composition, microphysical properties, and climate effects of aerosols in the ATAL have been the subject of discussion over the past decade. In thi...
https://www.oru.se/english/schools/science-and-technology/conferenses/ispac-september-9-12-2019/
Hydroxyl radical (OH) plays critical roles within the troposphere, such as determining the lifetime of methane (CH4), yet is challenging to model due to its fast cycling and dependence on a multitude of sources and sinks. As a result, the reasons for variations in OH and the resulting CH4 lifetime (τCH4), both between models and in time, are diffic...
A new module has been implemented in the ECHAM5/MESSy Atmospheric Chemistry (EMAC) Model that simulates cloud related processes on a much smaller grid. This so called superparametrisation acts as a replacement for the convection parametrisation and large-scale cloud scheme. The concept of embedding an ensemble of cloud resolving models (CRMs) insid...
The new submodel SVOC for the Modular Earth Submodel System (MESSy) was developed and applied within the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model to simulate the atmospheric cycling and air–surface exchange processes of semivolatile organic pollutants. Our focus is on four polycyclic aromatic hydrocarbons (PAHs) of largely varying properties...
Enhanced aerosol abundance in the upper troposphere and lower stratosphere (UTLS) associated with the Asian summer monsoon (ASM), is referred to as the Asian Tropopause Aerosol Layer (ATAL). The chemical composition, microphysical properties and climate effects of aerosols in the ATAL have been the subject of discussion over the past decade. In thi...
Human activities lead to an increase of emissions of air pollutants influencing the chemical composition of urban air. Chemical reactions and aerosol formation processes in urban areas in turn are altered due to increased temperature, reduced humidity and modified urban-rural trace substance mixture. Urban-rural circulation patterns driven by the s...
Climate sensitive urban planning involves the implementation of green infrastructure as one measure to mitigate excessive heat in urban areas. Depending on thermal conditions, certain trees tend to emit more biogenic volatile organic compounds, which act as precursors for ozone formation, thus hampering air quality. Combining a theoretical approach...
The excessive warming of impervious surfaces and additional release of anthropogenic heat promotes urban heat island (UHI) formation. Human activities lead to an increase of emissions of air pollutants which in turn influences the chemical composition of urban air. Anthropogenic aerosols either produced locally or transported from remote areas are...
The new submodel SVOC for the Modular Earth Submodel System (MESSy) was developed and applied within the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model to simulate the atmospheric cycling and air-surface exchange processes of semivolatile organic pollutants. Our focus is on four polycyclic aromatic hydrocarbons (PAHs) of largely varying properties...
Recently, the aerosol microphysics submodel MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, third generation) was introduced as a successor to MADE and MADE-in. It includes nine aerosol species and nine lognormal modes to represent aerosol particles of three different mixing states throughout the aerosol size spectr...
A comprehensive ice nucleation parameterization has been implemented in the global chemistry-climate model EMAC to improve the representation of ice crystal number concentrations (ICNCs). The parameterization of Barahona and Nenes (2009, hereafter BN09) allows for the treatment of ice nucleation taking into account the competition for water vapour...
Recently, the aerosol microphysics submodel MADE3 was introduced as a successor to MADE and MADE-in. It includes nine aerosol species and nine lognormal modes to represent aerosol particles of three different mixing states throughout the aeroso size spectrum. Here we describe the implementation of the most recent version of MADE3 into the atmospher...
Earth System Models (ESMs) are invaluable tools that have emerged from decades of research modelling the earth system. Central to this development has been the coupling of previously separate model types, such as ocean, atmospheric and vegetation models, to provide interactive feedbacks between these earth system components. Here we present the ini...
A comprehensive ice nucleation parameterization has been implemented in the global chemistry-climate model EMAC to realistically represent ice crystal number concentrations. The parameterization of Barahona and Nenes (2009, hereafter BN09) allows the treatment of ice nucleation, taking into account the competition for water vapour between homogeneo...
This study uses the EMAC atmospheric chemistry-climate model to simulate cloud properties with a prognostic cloud droplet nucleation scheme. We present modeled global distributions of cloud condensation nuclei (CCN) number concentrations and CCN activation rates, together with the effective hygroscopicity parameter κ, to describe the aerosol chemic...
We present a sensitivity study on transatlantic dust transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the dust outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral dust, by using the EMAC model following . To char...
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-troposph...
For the first time, a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSy-fied ECHAM and COSMO models nested n times. It features an online coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called C...
Lightning represents one of the dominant emission source 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 troposphe...
The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a base model via a highly flexible data management facility (Jöckel et al., 2010). In the present paper we present the four new radiation related submodels RAD, AEROPT, CLOUDOPT, and ORBIT. The submodel RAD (including the shortwave radiation scheme RAD_FUBRAD) si...
Three types of reference simulations, as recommended by the
Chemistry–Climate Model Initiative (CCMI), have been performed with version 2.51 of the European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC)
model:
hindcast simulations (1950–2011), hindcast simulations with...
Aerosols have important impacts on air quality and climate, but the processes
affecting their removal from the atmosphere are not fully understood and are
poorly constrained by observations. This makes modelled aerosol lifetimes
uncertain. In this study, we make use of an observational constraint on
aerosol lifetimes provided by radionuclide measur...
For the first time a simulation incorporating tropospheric and stratospheric chemistry using the newly developed MECO(n) model system is performed. MECO(n) is short for MESSyfied ECHAM and COSMO model nested n-times. It features an on-line coupling of the COSMO-CLM model, equipped with the Modular Earth Submodel System (MESSy) interface (called COS...
The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a basemodel via a highly flexible data management facility (Jöckel et al., 2010). In the present paper we present the four new radiation related submodels RAD, AEROPT, CLOUDOPT and ORBIT. The submodel RAD (with shortwave radiation scheme RAD_FUBRAD) simulates the...
The Community Earth System Model (CESM1), maintained by the United States National Centre for Atmospheric Research (NCAR) is connected with the Modular Earth Submodel System (MESSy). For the MESSy user community, this offers many new possibilities. The option to use the Community Atmosphere Model (CAM) atmospheric dynamical cores, especially the st...
With version 2.51 of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model three types of reference simulations as recommended by the Chemistry-Climate Model Initiative (CCMI) have been performed: hindcast simulations (1950–2011), hindcast simulations with specified dynamics (1978–2013), i.e., nudged towards ERA-Interim reanalysis data, and combined h...
Aerosols have important impacts on air quality and climate, but the
processes affecting their removal from the atmosphere are not fully
understood and are poorly constrained by observations. This makes
modelled aerosol lifetimes uncertain. In this study, we make use of an
observational constraint on aerosol lifetimes provided by radionuclide
measur...
The convective transport module, CVTRANS, of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model has been revised to better represent the physical flows and incorporate recent findings on the properties of the convective plumes. The modifications involve (i) applying intermediate time stepping based on a settable criterion, (ii) using an analytic ex...
The aerosol optical depth (AOD) trend between 2001 and 2010 is estimated
globally and regionally from observations and results from simulations with
the EMAC (ECHAM5/MESSy Atmospheric Chemistry) model. Although interannual
variability is applied only to anthropogenic and biomass-burning emissions,
the model is able to quantitatively reproduce the A...
Abstract. The aerosol optical depth (AOD) trend between 2001 and 2010 is estimated globally and regionally from observations and results from simulations with the EMAC (ECHAM5/MESSy Atmospheric Chemistry) model. Although interannual variability is applied only to anthropogenic and biomass-burning emissions, the model is able to quantitatively repro...
The convective transport module, CVTRANS, of the ECHAM/MESSy
Atmospheric Chemistry (EMAC) model has been revised to better
represent the physical flows and incorporate recent findings on the
properties of the convective plumes. The modifications involve
(i) applying intermediate time stepping based on a settable
criterion, (ii) using an analytic ex...
Multiyear simulations with the atmospheric chemistry general circulation model EMAC with a microphysical modal aerosol module at high vertical resolution demonstrate that the sulfur gases COS and SO2, the latter from low-latitude and midlatitude volcanic eruptions, predominantly control the formation of stratospheric aerosol. Marine dimethyl sulfid...
The modelling of aerosol radiative forcing is a major cause of uncertainty in
the assessment of global and regional atmospheric energy budgets and climate
change. One reason is the strong dependence of the aerosol optical properties
on the mixing state of aerosol components, such as absorbing black carbon and,
predominantly scattering sulfates. Usi...
The aerosol Optical Depth (AOD) trend between 2001–2010 is estimated globally and regionally from
observations and from model simulations. The model is able to reproduce quantitatively the AOD
trends as observed by MODIS satellite sensor, while some discrepancies are found when compared to
MISR and SeaWIFS observations. Thanks to an additional simu...
This study uses the EMAC atmospheric chemistry-climate model to simulate cloud properties and estimate cloud radiative effects induced by aerosols. We have tested two prognostic cloud droplet nucleation parameterizations, i.e., the standard STN (osmotic coefficient model) and hybrid (HYB, replacing the osmotic coefficient by the κ hygroscopicity pa...
In the last decades several convection parameterisations have been developed
to consider the impact of small-scale unresolved processes in Earth System
Models associated with convective clouds. Global model simulations, which
have been performed under current climate conditions with different
convection schemes, significantly differ among each othe...
The modelling of aerosol radiative forcing is a major cause of uncertainty in the assessment of global and regional atmospheric energy budgets and climate change. One reason is the strong dependence of the aerosol optical properties on the mixing state of aerosol components like black carbon and sulphates. Using a new column version of the aerosol...
This paper evaluates the current status of global modeling of the organic aerosol (OA) in the troposphere and analyzes the differences between models as well as between models and observations. Thirty-one global chemistry transport models (CTMs) and general circulation models (GCMs) have participated in this intercomparison, in the framework of Aer...
This paper evaluates the current status of global modeling of the
organic aerosol (OA) in the troposphere and analyzes the differences
between models as well as between models and observations.
Thirty-one global chemistry/transport and general circulation models
have participated in this intercomparison, in the framework of
AeroCom phase II. The si...
We apply a cloud slicing technique (CST), originally developed for
Total Ozone Mapping Spectrometer (TOMS) ozone observations, to CO vertical
column densities retrieved from the SCanning Imaging Absorption spectroMeter
for Atmospheric CHartographY (SCIAMACHY). CST makes use of the shielding
effect of clouds and combines trace gas column measurement...
Recently, realistic simulation of nitrous acid (HONO) based on the
HONO / NOx ratio of 0.02 was found to have a significant impact on the
global budgets of HOx (OH + HO2) and gas phase oxidation
products in polluted regions, especially in winter when other photolytic
sources are of minor importance. It has been reported that
chemistry-transport mod...
Many of the next generation of global climate models will include
aerosol schemes which explicitly simulate the microphysical
processes that determine the particle size distribution. These
models enable aerosol optical properties and cloud condensation
nuclei (CCN) concentrations to be determined by fundamental aerosol
processes, which should lead...
As efforts to recognize the Anthropocene as a new epoch of geological time are mounting, the controversial debate about the time of its beginning continues. Here, we suggest the term Palaeoanthropocene for the period between the first, barely recognizable, anthropogenic environmental changes and the industrial revolution when anthropogenically indu...
In the last decades several convection parameterisations have been
developed to consider the impact of small-scale unresolved processes in
Earth System Models associated with convective clouds. Global model
simulations, which have been performed under current climate conditions
with different convection schemes, significantly differ among each othe...
Nitrous acid (HONO) photolysis can significantly increase HOx (OH+HO2) radical formation, enhancing organic and inorganic oxidation products in polluted regions, especially during winter. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that HONO can significantly enhance...
We apply a cloud slicing technique (CST), originally developed for Total Ozone Mapping Spectrometer (TOMS) ozone observations, to CO vertical column densities retrieved from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). CST makes use of the shielding effect of clouds and combines trace gas column measurement...
Major population centers (MPCs), or megacities, represent the largest of growing urban agglomerations with major societal and environmental implications. In terms of air quality, they are seen as localized but strong emission sources of aerosols and trace gases which in turn affect air pollution levels in the city or in downwind regions. In the sta...
