scholarly journals Simulation of organics in the atmosphere: evaluation of EMACv2.54 with the Mainz Organic Mechanism (MOM) coupled to the ORACLE (v1.0) submodel

2021 ◽  
Author(s):  
Andrea Pozzer ◽  
Simon Reifenberg ◽  
Vinod Kumar ◽  
Bruno Franco ◽  
Domenico Taraborrelli ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
Organic Aerosol ◽  
Efficient Estimation ◽  
Chemical Degradation ◽  
Aerosol Formation ◽  
Organic Species ◽  
Volatile Organic ◽  
Good Agreement

Abstract. 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 organic species up to five carbon atoms and a simplified mechanism for larger molecules. Second, the ORACLE submodel (version 1.0) considers now condensation on aerosols for all organics in the mechanism. Parameterizations for aerosol yields are used only for the lumped species that are not included in the explicit mechanism. The simultaneous usage of MOM and ORACLE allows an efficient estimation, not only of the chemical degradation of the simulated volatile organic compounds, but also of the contribution of organics to the growth and fate of (organic) aerosol, with a complexity of the mechanism largely increased compared to EMAC simulations with more simplified chemistry. The model evaluation presented here reveals that the OH concentration is well reproduced globally, while significant biases for observed oxygenated organics are present. We also investigate the general properties of the aerosols and their composition, showing that the more sophisticated and process-oriented secondary aerosol formation does not degrade the good agreement of previous model configurations with observations at the surface, allowing further research in the field of gas-aerosol interactions.

scholarly journals Energetic particle precipitation in ECHAM5/MESSy – Part 2: Solar proton events

2010 ◽  
Vol 10 (15) ◽  
pp. 7285-7302 ◽  
Author(s):  
A. J. G. Baumgaertner ◽  
P. Jöckel ◽  
H. Riede ◽  
G. Stiller ◽  
B. Funke
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Solar Proton ◽  
No Production ◽  
Particle Precipitation ◽  
Total Column Ozone ◽  
Solar Proton Events ◽  
Good Agreement

Abstract. The atmospheric chemistry general circulation model ECHAM5/MESSy (EMAC) has been extended by processes that parameterize particle precipitation. Several types of particle precipitation that directly affect NOy and HOx concentrations in the middle atmosphere are accounted for and discussed in a series of papers. In part 1, the EMAC parameterization for NOx produced in the upper atmosphere by low-energy electrons is presented. Here, we discuss production of NOy and HOx associated with Solar Proton Events (SPEs). A submodel that parameterizes the effects of precipitating protons, based on flux measurements by instruments on the IMP or GOES satellites, was added to the EMAC model. Production and transport of NOy and HOx, as well as effects on other chemical species and dynamics during the 2003 Halloween SPEs are presented. Comparisons with MIPAS/ENVISAT measurements of a number of species affected by the SPE are shown and discussed. There is good agreement for NO2, but a severe disagreement is found for N2O similar to other studies. We discuss the effects of an altitude dependence of the N/NO production rate on the N2O and NOy changes during the SPE. This yields a modified parameterization that shows mostly good agreement between MIPAS and model results for NO2, N2O, O3, and HOCl. With the ability of EMAC to relax the model meteorology to observations, accurate assessment of total column ozone loss is also possible, yielding a loss of approximately 10 DU at the end of November. Discrepancies remain for HNO3, N2O5, and ClONO2, which are likely a consequence from the missing cluster ion chemistry and ion-ion recombination in the EMAC model as well as known issues with the model's NOy partitioning.

scholarly journals Energetic particle precipitation in ECHAM5/MESSy – Part 2: Solar Proton Events

2010 ◽  
Vol 10 (2) ◽  
pp. 4501-4542 ◽  
Author(s):  
A. J. G. Baumgaertner ◽  
P. Jöckel ◽  
H. Riede ◽  
G. Stiller ◽  
B. Funke
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Solar Proton ◽  
No Production ◽  
Particle Precipitation ◽  
Total Column Ozone ◽  
Solar Proton Events ◽  
Good Agreement

Abstract. The atmospheric chemistry general circulation model ECHAM5/MESSy (EMAC) has been extended by processes that parameterize particle precipitation. Several types of particle precipitation that directly affect NOy and HOx concentrations in the middle atmosphere are accounted for and discussed in a series of papers. In part 1, the EMAC parameterization for NOx produced in the upper atmosphere by low-energy electrons is presented. Here, we discuss production of NOy and HOx associated with Solar Proton Events (SPEs). A submodel that parameterizes the effects of precipitating protons, based on flux measurements by instruments on the IMP or GOES satellites, was added to the EMAC model. Production and transport of NOy and HOx, as well as effects on other chemical species and dynamics during the 2003 Halloween SPEs are presented. Comparisons with MIPAS/ENVISAT measurements of a number of species affected by the SPE are shown and discussed. There is good agreement for NO2, but a severe disagreement is found for N2O similar to other studies. We discuss the effects of an altitude dependence of the N/NO production rate on the N2O and NOy changes during the SPE. This yields a modified parameterization that shows good agreement between MIPAS and model results for NO2, N2O, O3, and HOCl. With the ability of EMAC to relax the model meteorology to observations, accurate assessment of total column ozone loss is also possible, yielding a loss of approximately 10 DU at the end of November. Discrepancies remain for HNO3, N2O5, and ClONO2, which are likely a consequence from the missing cluster ion chemistry in the EMAC model as well as known issues with the model's NOy partitioning.

scholarly journals Microphysical simulations of new particle formation in the upper troposphere and lower stratosphere

2011 ◽  
Vol 11 (17) ◽  
pp. 9303-9322 ◽  
Author(s):  
J. M. English ◽  
O. B. Toon ◽  
M. J. Mills ◽  
F. Yu
Keyword(s):  
Atmospheric Chemistry ◽  
Radiative Forcing ◽  
General Circulation ◽  
Lower Stratosphere ◽  
Three Dimensional ◽  
Circulation Model ◽  
Number Concentration ◽  
Aerosol Formation ◽  
Upper Troposphere ◽  
Microphysical Processes

Abstract. Using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA), we studied aerosol formation and microphysics in the upper troposphere and lower stratosphere (UTLS) as well as the middle and upper stratosphere based on three nucleation schemes (two binary homogeneous schemes and an ion-mediated scheme related to one of the binary schemes). Simulations suggest that ion-mediated nucleation rates in the UTLS are 25 % higher than its related binary scheme, but that the rates predicted by the two binary schemes vary by two orders of magnitude. None of the nucleation schemes is superior at matching the limited observations available at the smallest sizes. However, it is found that coagulation, not nucleation, controls number concentration at sizes greater than approximately 10 nm. Therefore, based on this study, processes relevant to atmospheric chemistry and radiative forcing in the UTLS are not sensitive to the choice of nucleation schemes. The dominance of coagulation over other microphysical processes in the UTLS is consistent with other recent work using microphysical models. Simulations using all three nucleation schemes compare reasonably well to observations of size distributions, number concentration across latitude, and vertical profiles of particle mixing ratio in the UTLS. Interestingly, we find that we need to include Van der Waals forces in our coagulation scheme to match the UTLS aerosol concentrations. We conclude that this model can reasonably represent sulfate microphysical processes in the UTLS, and that the properties of particles at atmospherically relevant sizes appear to be insensitive to the details of the nucleation scheme. We also suggest that micrometeorites, which are not included in this model, dominate the aerosol properties in the upper stratosphere above about 30 km.

scholarly journals Global impact of monocyclic aromatics on tropospheric composition

2017 ◽  
Author(s):  
David Cabrera-Perez ◽  
Domenico Taraborrelli ◽  
Jos Lelieveld ◽  
Thorsten Hoffmann ◽  
Andrea Pozzer
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Aromatic Compounds ◽  
Urban Areas ◽  
General Circulation ◽  
Organic Aerosol ◽  
Global Scale ◽  
Chemical Mechanism ◽  
Aerosol Formation ◽  
Mixing Ratios

Abstract. Aromatic compounds are reactive species influencing ozone formation, OH concentrations and organic aerosol formation. An assessment of their impacts on the gas-phase composition at a global scale has been performed using a general circulation atmospheric-chemistry model. Globally, we found a small annual average net decrease (less than 3 %) in global OH, ozone, and NOx mixing ratios when aromatic compounds are included in the chemical mechanism. This inclusion of aromatics also results in CO mixing ratio increases, which cause a general decrease in OH concentrations. The largest changes are found in glyoxal and NO3, with increases in the atmospheric burden of 10 % and 6 %, respectively. Regionally, significant differences were found particularly in high NOx regime areas, with an increase of up to 4 % in O3 mixing ratios and 8 % in OH concentrations. NO3 increased by more than 30 % in several regions of the northern hemisphere, and glyoxal increased up to 40 % in Europe and Asia. Large increases in formaldehyde were found in urban areas. Although the relative impact of aromatics at the global scale is limited, at a regional level they are important in atmospheric chemistry.

scholarly journals A new radiation infrastructure for the Modular Earth Submodel System (MESSy, based on version 2.51)

2016 ◽  
Author(s):  
Simone Dietmüller ◽  
Patrick Jöckel ◽  
Holger Tost ◽  
Markus Kunze ◽  
Cathrin Gellhorn ◽  
...  
Keyword(s):  
Optical Properties ◽  
Atmospheric Chemistry ◽  
Radiative Forcing ◽  
General Circulation ◽  
Circulation Model ◽  
Shortwave Radiation ◽  
Aerosol Optical Properties ◽  
On Line ◽  
User Friendly ◽  
Radiation Scheme

Abstract. 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 radiative transfer, the submodel AEROPT calculates the aerosol optical properties, the submodel CLOUDOPT calculates the cloud optical properties, and the submodel ORBIT is responsible for Earth orbit calculations. These submodels are coupled via the standard MESSy infrastructure and are largely based on the original radiation scheme of the general circulation model ECHAM5, however, expanded with additional features. These features comprise, among others, user-friendly and flexibly controllable (by namelists) on-line radiative forcing calculations by multiple diagnostic calls of the radiation routines. With this, it is now possible to calculate radiative forcing (instantaneous as well as stratosphere adjusted) of various greenhouse gases simultaneously in only one simulation, as well as the radiative forcing of cloud perturbations. Examples of on-line radiative forcing calculations in the ECHAM/MESSy Atmospheric Chemistry (EMAC) model are presented.

scholarly journals Development of a secondary organic aerosol formation mechanism: comparison with smog chamber experiments and atmospheric measurements

2007 ◽  
Vol 7 (3) ◽  
pp. 8361-8393 ◽  
Author(s):  
L. E. Olcese ◽  
J. E. Penner ◽  
S. Sillman
Keyword(s):  
New England ◽  
Formation Mechanism ◽  
General Circulation ◽  
Circulation Model ◽  
Average Error ◽  
Smog Chamber ◽  
Vapor Pressures ◽  
Aerosol Formation ◽  
Atmospheric Measurements ◽  
Chamber Measurements

Abstract. A new mechanism to simulate the formation of secondary organic aerosols (SOA) from reactive primary hydrocarbons is presented, together with comparisons with experimental smog chamber results and ambient measurements found in the literature. The SOA formation mechanism is based on an approach using calculated vapor pressures and a selection of species that can partition to the aerosol phase from a gas phase photochemical mechanism. The mechanism has been validated against smog chamber measurements using α-pinene, xylene and toluene as SOA precursors, and has an average error of 17%. Qualitative comparisons with smog chamber measurements using isoprene were also performed. A comparison against SOA production in the TORCH 2003 experiment (atmospheric measurements) had an average error of only 12%. This contrasts with previous efforts, in which it was necessary to increase partition coefficients by a factor of 500 in order to match the observed values. Calculations for rural and urban-influenced regions in the eastern U.S. suggest that most of the SOA is biogenic in origin, mainly originated from isoprene. A 0-dimensional calculation based on the New England Air Quality Study also showed good agreement with measured SOA, with about 40% of the total SOA from anthropogenic precursors. This mechanism can be implemented in a general circulation model (GCM) to estimate global SOA formation under ambient NOx and HOx levels.

scholarly journals Simulating organic species with the global atmospheric chemistry general circulation model ECHAM5/MESSy1: a comparison of model results with observations

2007 ◽  
Vol 7 (1) ◽  
pp. 127-202 ◽  
Author(s):  
A. Pozzer ◽  
P. Jöckel ◽  
H. Tost ◽  
R. Sander ◽  
L. Ganzeveld ◽  
...  
Keyword(s):  
General Circulation Model ◽  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
Oxygenated Compounds ◽  
Reference Simulation ◽  
Sensitivity Studies ◽  
Systematic Biases ◽  
Using Data ◽  
Prior Analysis

Abstract. The atmospheric-chemistry general circulation model ECHAM5/MESSy1 is evaluated with observations of different organic ozone precursors. This study continues a prior analysis which focused primarily on the representation of atmospheric dynamics and ozone. We use the results of the same reference simulation and apply a statistical analysis using data from numerous field campaigns. The results serve as a basis for future improvements of the model system. ECHAM5/MESSy1 generally reproduces the spatial distribution and the seasonal cycle of carbon monoxide (CO) very well. However, for the background in the northern hemisphere we obtain a negative bias (mainly due to an underestimation of emissions from fossil fuel combustion), and in the high latitude southern hemisphere a yet unexplained positive bias. The model results agree well with observations of alkanes, whereas severe problems in the simulation of alkenes are present. For oxygenated compounds the results are ambiguous: The model results are in good agreement with observations of formaldehyde, but systematic biases are present for methanol and acetone. The discrepancies between the model results and the observations are explained (partly) by means of sensitivity studies.

scholarly journals Application of the Statistical Oxidation Model (SOM) to Secondary Organic Aerosol formation from photooxidation of C<sub>12</sub> alkanes

2013 ◽  
Vol 13 (3) ◽  
pp. 1591-1606 ◽  
Author(s):  
C. D. Cappa ◽  
X. Zhang ◽  
C. L. Loza ◽  
J. S. Craven ◽  
L. D. Yee ◽  
...  
Keyword(s):  
Formation Process ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Atomic Ratio ◽  
Model Parameters ◽  
Reaction Products ◽  
Aerosol Formation ◽  
Volatile Organic ◽  
Oxidation Model ◽  
Mechanism Of Oxidation

Abstract. Laboratory chamber experiments are the main source of data on the mechanism of oxidation and the secondary organic aerosol (SOA) forming potential of volatile organic compounds. Traditional methods of representing the SOA formation potential of an organic do not fully capture the dynamic, multi-generational nature of the SOA formation process. We apply the Statistical Oxidation Model (SOM) of Cappa and Wilson (2012) to model the formation of SOA from the formation of the four C12 alkanes, dodecane, 2-methyl undecane, cyclododecane and hexylcyclohexane, under both high- and low-NOx conditions, based upon data from the Caltech chambers. In the SOM, the evolution of reaction products is defined by the number of carbon (NC) and oxygen (NO) atoms, and the model parameters are (1) the number of oxygen atoms added per reaction, (2) the decrease in volatility upon addition of an oxygen atom and (3) the probability that a given reaction leads to fragmentation of the molecules. Optimal fitting of the model to chamber data is carried out using the measured SOA mass concentration and the aerosol O:C atomic ratio. The use of the kinetic, multi-generational SOM is shown to provide insights into the SOA formation process and to offer promise for application to the extensive library of existing SOA chamber experiments that is available.

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