scholarly journals Observed and simulated global distribution and budget of atmospheric C<sub>2</sub>−C<sub>5</sub> alkanes

2010 ◽  
Vol 10 (1) ◽  
pp. 615-655
Author(s):  
A. Pozzer ◽  
J. Pollmann ◽  
D. Taraborrelli ◽  
P. Jöckel ◽  
D. Helmig ◽  
...  
Keyword(s):  
General Circulation Model ◽  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
The Other ◽  
Primary Sources ◽  
Model Output ◽  
Anthropogenic Emission ◽  
Sampling Network ◽  
Global Coverage

Abstract. The primary sources and atmospheric chemistry of C2−C5 alkanes have been incorporated into the atmospheric chemistry general circulation model EMAC. Model output is compared with new observations from the NOAA/ESRL GMD cooperative air sampling network. Based on the global coverage of the data, two different anthropogenic emission datasets for C4−C5 alkanes, widely used in the modelling community, are evaluated. We show that the model reproduces the main atmospheric features of the C2−C5 alkanes (e.g., seasonality). While the simulated values of ethane and propane are within a 20% range of the measurements, larger deviations are found for the other tracers. Finally the effect of C3−C5 alkanes on the concentration of acetone and acetaldehyde are assessed. Their chemical sources are largely controlled by the reaction with OH, while the reactions with NO3 and Cl contribute only to a little extent. The total amount of acetone produced by propane, i-butane and i-pentane oxidation is 11.2 Tg/yr, 4.2 Tg/yr and 5.8 Tg/yr, respectively. Moreover, 3.1, 3.3, 1.4 and 4.8 Tg/yr of acetaldehyde are formed by the oxidation of propane, n-butane, n-pentane and i-pentane, respectively.

scholarly journals Observed and simulated global distribution and budget of atmospheric C<sub>2</sub>-C<sub>5</sub> alkanes

2010 ◽  
Vol 10 (9) ◽  
pp. 4403-4422 ◽  
Author(s):  
A. Pozzer ◽  
J. Pollmann ◽  
D. Taraborrelli ◽  
P. Jöckel ◽  
D. Helmig ◽  
...  
Keyword(s):  
General Circulation Model ◽  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
The Other ◽  
Primary Sources ◽  
Model Output ◽  
Anthropogenic Emission ◽  
Sampling Network ◽  
Global Coverage

Abstract. The primary sources and atmospheric chemistry of C2-C5 alkanes were incorporated into the atmospheric chemistry general circulation model EMAC. Model output is compared with new observations from the NOAA/ESRL GMD Cooperative Air Sampling Network. Based on the global coverage of the data, two different anthropogenic emission datasets for C4-C5 alkanes, widely used in the modelling community, are evaluated. We show that the model reproduces the main atmospheric features of the C2-C5 alkanes (e.g., seasonality). While the simulated values for ethane and propane are within a 20% range of the measurements, larger deviations are found for the other tracers. According to the analysis, an oceanic source of butanes and pentanes larger than the current estimates would be necessary to match the observations at some coastal stations. Finally the effect of C2-C5 alkanes on the concentration of acetone and acetaldehyde are assessed. Their chemical sources are largely controlled by the reaction with OH, while the reactions with NO3 and Cl contribute only to a little extent. The total amount of acetone produced by propane, i-butane and i-pentane oxidation is 11.2 Tg/yr, 4.3 Tg/yr, and 5.8 Tg/yr, respectively. Moreover, 18.1, 3.1, 3.4, 1.4 and 4.8 Tg/yr of acetaldehyde are formed by the oxidation of ethane, propane, n-butane, n-pentane and i-pentane, respectively.

scholarly journals C<sub>3</sub>-C<sub>5</sub> alkanes in the atmosphere: concentration, seasonal cycle and contribution to the atmospheric budgets of acetone and acetaldehyde

2009 ◽  
Vol 9 (1) ◽  
pp. 1939-1976 ◽  
Author(s):  
A. Pozzer ◽  
J. Pollmann ◽  
D. Taraborrelli ◽  
P. Jöckel ◽  
D. Helmig ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
Measurement Range ◽  
The Other ◽  
Measurement Standard ◽  
Mixing Ratios ◽  
Oxygenated Compounds ◽  
Sampling Network ◽  
Propane Butane

Abstract. The atmospheric chemistry of C3-C5 alkanes has been incorporated in the atmospheric-chemistry general circulation model EMAC. Model output is compared with observations from the NOAA/ESRL GMD cooperative air sampling network. A new series of measurements is used to evaluate the model in representing C3-C5 alkanes (i.e. propane, isobutane, butane, isopentane and pentane). While the representation of propane is within the measurement standard deviation, some deviations are found for the other tracers. The model is able to reproduce the main features of the C3-C5 alkanes (e.g., seasonality). However, in the Northern Hemisphere during winter the mixing ratios of these alkanes are generally overestimated. Conversely, the model shows an underestimation in the Southern Hemisphere. Moreover, only for iso-pentane there is a net overestimation of the mixing ratios, while for the other alkanes, the results are at the higher end of the measurement range. The effects of the C3-C5 alkanes to atmospheric acetone and acetaldehyde are quantified. The total amount of acetone produced by propane, isobutane and isopentane oxidation is 11.6 Tg/yr, 4.2 Tg/yr and 5.8 Tg/yr, respectively. These chemical sources are largely controlled by the reaction with OH, while the reactions with NO3 and Cl contribute only to a little extent. Moreover, 3.1, 4.5, 1.9 and 6.7 Tg/yr of acetaldehyde are formed from the oxidation of propane, butane, pentane and isopentane, respectively. Also for acetaldehyde, the formation is controlled by the reaction of alkanes with OH. However, since isopentane is generally overestimated, its contribution to the production of these oxygenated compounds represents an upper limit.

scholarly journals Using Different Formulations of the Transformed Eulerian Mean Equations and Eliassen–Palm Diagnostics in General Circulation Models

2010 ◽  
Vol 67 (6) ◽  
pp. 1983-1995 ◽  
Author(s):  
Steven C. Hardiman ◽  
David G. Andrews ◽  
Andy A. White ◽  
Neal Butchart ◽  
Ian Edmond
Keyword(s):  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
General Circulation Models ◽  
Primitive Equations ◽  
Model Output ◽  
Vertical Coordinate ◽  
Order Of Magnitude ◽  
Transformed Eulerian Mean

Abstract Transformed Eulerian mean (TEM) equations and Eliassen–Palm (EP) flux diagnostics are presented for the general nonhydrostatic, fully compressible, deep atmosphere formulation of the primitive equations in spherical geometric coordinates. The TEM equations are applied to a general circulation model (GCM) based on these general primitive equations. It is demonstrated that a naive application in this model of the widely used approximations to the EP diagnostics, valid for the hydrostatic primitive equations using log-pressure as a vertical coordinate and presented, for example, by Andrews et al. in 1987 can lead to misleading features in these diagnostics. These features can be of the same order of magnitude as the diagnostics themselves throughout the winter stratosphere. Similar conclusions are found to hold for “downward control” calculations. The reasons are traced to the change of vertical coordinate from geometric height to log-pressure. Implications for the modeling community, including comparison of model output with that from reanalysis products available only on pressure surfaces, are discussed.

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 On the bias correction of general circulation model output for Indian summer monsoon

2012 ◽  
Vol 20 (3) ◽  
pp. 349-356 ◽  
Author(s):  
Nachiketa Acharya ◽  
Surajit Chattopadhyay ◽  
U. C. Mohanty ◽  
S. K. Dash ◽  
L. N. Sahoo
Keyword(s):  
General Circulation Model ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Bias Correction ◽  
General Circulation ◽  
Circulation Model ◽  
Model Output ◽  
General Circulation Model Output

scholarly journals Development of the global atmospheric chemistry general circulation model BCC-GEOS-Chem v1.0: model description and evaluation

2020 ◽  
Vol 13 (9) ◽  
pp. 3817-3838
Author(s):  
Xiao Lu ◽  
Lin Zhang ◽  
Tongwen Wu ◽  
Michael S. Long ◽  
Jun Wang ◽  
...  
Keyword(s):  
General Circulation Model ◽  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
General Circulation ◽  
Climate Models ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Circulation Model ◽  
Satellite Observations ◽  
Model Description

Abstract. Chemistry plays an indispensable role in investigations of the atmosphere; however, many climate models either ignore or greatly simplify atmospheric chemistry, limiting both their accuracy and their scope. We present the development and evaluation of the online global atmospheric chemical model BCC-GEOS-Chem v1.0, coupling the GEOS-Chem chemical transport model (CTM) as an atmospheric chemistry component in the Beijing Climate Center atmospheric general circulation model (BCC-AGCM). The GEOS-Chem atmospheric chemistry component includes detailed tropospheric HOx–NOx–volatile organic compounds–ozone–bromine–aerosol chemistry and online dry and wet deposition schemes. We then demonstrate the new capabilities of BCC-GEOS-Chem v1.0 relative to the base BCC-AGCM model through a 3-year (2012–2014) simulation with anthropogenic emissions from the Community Emissions Data System (CEDS) used in the Coupled Model Intercomparison Project Phase 6 (CMIP6). The model captures well the spatial distributions and seasonal variations in tropospheric ozone, with seasonal mean biases of 0.4–2.2 ppbv at 700–400 hPa compared to satellite observations and within 10 ppbv at the surface to 500 hPa compared to global ozonesonde observations. The model has larger high-ozone biases over the tropics which we attribute to an overestimate of ozone chemical production. It underestimates ozone in the upper troposphere which is likely due either to the use of a simplified stratospheric ozone scheme or to biases in estimated stratosphere–troposphere exchange dynamics. The model diagnoses the global tropospheric ozone burden, OH concentration, and methane chemical lifetime to be 336 Tg, 1.16×106 molecule cm−3, and 8.3 years, respectively, which is consistent with recent multimodel assessments. The spatiotemporal distributions of NO2, CO, SO2, CH2O, and aerosol optical depth are generally in agreement with satellite observations. The development of BCC-GEOS-Chem v1.0 represents an important step for the development of fully coupled earth system models (ESMs) in China.

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