scholarly journals The influence of natural and anthropogenic secondary sources on the glyoxal global distribution

2008 ◽  
Vol 8 (16) ◽  
pp. 4965-4981 ◽  
Author(s):  
S. Myriokefalitakis ◽  
M. Vrekoussis ◽  
K. Tsigaridis ◽  
F. Wittrock ◽  
A. Richter ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Transport Model ◽  
Hot Spot ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Chemical Production ◽  
Secondary Sources ◽  
Voc Oxidation ◽  
Primary Emissions ◽  
The Impact

Abstract. Glyoxal, the smallest dicarbonyl, which has recently been observed from space, is expected to provide indications on volatile organic compounds (VOC) oxidation and secondary aerosol formation in the troposphere. Glyoxal (CHOCHO) is known to be mostly of natural origin and is produced during biogenic VOC oxidation. However, a number of anthropogenically emitted hydrocarbons, like acetylene and aromatics, have been positively identified as CHOCHO precursors. The present study investigates the contribution of pollution to the CHOCHO levels by taking into account the secondary chemical formation of CHOCHO from precursors emitted from biogenic, anthropogenic and biomass burning sources. The impact of potential primary land emissions of CHOCHO is also investigated. A global 3-dimensional chemistry transport model of the troposphere (TM4-ECPL) able to simulate the gas phase chemistry coupled with all major aerosol components is used. The secondary anthropogenic contribution from fossil fuel and industrial VOCs emissions oxidation to the CHOCHO columns is found to reach 20–70% in the industrialized areas of the Northern Hemisphere and 3–20% in the tropics. This secondary CHOCHO source is on average three times larger than that from oxidation of VOCs from biomass burning sources. The chemical production of CHOCHO is calculated to equal to about 56 Tg y−1 with 70% being produced from biogenic hydrocarbons oxidation, 17% from acetylene, 11% from aromatic chemistry and 2% from ethene and propene. CHOCHO is destroyed in the troposphere primarily by reaction with OH radicals (23%) and by photolysis (63%), but it is also removed from the atmosphere through wet (8%) and dry deposition (6%). Potential formation of secondary organic aerosol through CHOCHO losses on/in aerosols and clouds is neglected here due to the significant uncertainties associated with the underlying chemistry. The global annual mean CHOCHO burden and lifetime in the model domain are estimated to be 0.02 Tg (equal to the global burden seen by SCIAMACHY over land for the year 2005) and about 3 h, respectively. The model results are compared with satellite observations of CHOCHO columns. When accounting only for the secondary sources of CHOCHO in the model, the model underestimates CHOCHO columns observed by satellites. This is attributed to an overestimate of CHOCHO sinks or a missing global source of about 20 Tg y−1. Using the current primary emissions of CHOCHO from biomass burning together with the anthropogenic combustion sources of about 7 Tg y−1 leads to an overestimate by the model over hot spot areas.

scholarly journals The influence of natural and anthropogenic secondary sources on the glyoxal global distribution

2008 ◽  
Vol 8 (1) ◽  
pp. 1673-1708 ◽  
Author(s):  
S. Myriokefalitakis ◽  
M. Vrekoussis ◽  
K. Tsigaridis ◽  
F. Wittrock ◽  
A. Richter ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Transport Model ◽  
Hot Spot ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Chemical Production ◽  
3 Dimensional ◽  
Secondary Sources ◽  
Voc Oxidation ◽  
Potential Formation

Abstract. Glyoxal, the smallest dicarbonyl, which has recently been observed from space, is expected to provide indications on VOC oxidation and secondary aerosol formation in the troposphere. Glyoxal is known to be mostly of natural origin and is produced during biogenic VOC oxidation. However, a number of anthropogenically emitted hydrocarbons, like acetylene and aromatics, have been positively identified as glyoxal precursors. The present study investigates the contribution of pollution emissions to the glyoxal levels by taking into account only the secondary chemical formation of glyoxal from precursors emitted from biogenic, anthropogenic and biomass burning sources. For this purpose, a global 3-dimensional chemistry transport model of the troposphere (TM4) able to simulate the gas phase chemistry coupled with all major aerosol components is used. The model results are compared with satellite observations of glyoxal columns over hot spot areas. According to TM4 model results, the anthropogenic contribution to the glyoxal columns is found to reach 70% in the industrialized areas of the northern hemisphere and up to 20% in the tropics. It is on average three times larger than the secondary production of glyoxal from biomass burning sources. The chemical production of glyoxal is calculated to equal about 56 Tg y−1 with 70% produced from biogenic hydrocarbons oxidation, 17% from acetylene, 11% from aromatic chemistry, and 2% from ethene and propene. Glyoxal is destroyed by reactions mainly with OH radicals (22%) and by photolysis (65%), but it is also removed from the atmosphere through wet (11%) and dry deposition (6%). Secondary organic aerosol potential formation through glyoxal losses on/in aerosols and clouds was neglected here due to the significant uncertainties associated with the underlying chemistry. The global annual mean glyoxal burden and lifetime in the model domain are estimated at 0.02 Tg and 3 h, respectively.

scholarly journals Improving the seasonal cycle and interannual variations of biomass burning aerosol sources

2003 ◽  
Vol 3 (4) ◽  
pp. 1211-1222 ◽  
Author(s):  
S. Generoso ◽  
F.-M. Bréon ◽  
Y. Balkanski ◽  
O. Boucher ◽  
M. Schulz
Keyword(s):  
Biomass Burning ◽  
Seasonal Cycle ◽  
Transport Model ◽  
Hot Spot ◽  
Fire Detection ◽  
Night Time ◽  
Biomass Burning Aerosol ◽  
Emissions Inventories ◽  
Aerosol Emissions ◽  
The Impact

Abstract. This paper suggests a method for improving current inventories of aerosol emissions from biomass burning. The method is based on the hypothesis that, although the total estimates within large regions are correct, the exact spatial and temporal description can be improved. It makes use of open fire detection from the ATSR instrument that is available since 1996. The emissions inventories are re-distributed in space and time according to the occurrence of open fires. Although the method is based on the night-time hot-spot product of the ATSR, other satellite biomass burning proxies (AVHRR, TRMM, GLOBSCAR and GBA2000) show similar distributions. The impact of the method on the emission inventories is assessed using an aerosol transport model, the results of which are compared to sunphotometer and satellite data. The seasonal cycle of aerosol load in the atmosphere is significantly improved in several regions, in particular South America and Australia. Besides, the use of ATSR fire detection may be used to account for interannual events, as is demonstrated on the large Indonesian fires of 1997, a consequence of the 1997-1998 El Niño. Despite these improvements, there are still some large discrepancies between the simulated and observed aerosol optical thicknesses resulting from biomass burning emissions.

scholarly journals Secondary organic aerosol formation from biomass burning emissions

2019 ◽  
Author(s):  
Christopher Y. Lim ◽  
David H. Hagan ◽  
Matthew M. Coggon ◽  
Abigail R. Koss ◽  
Kanako Sekimoto ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Secondary Organic Aerosol ◽  
Total Concentration ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Atmospheric Aging ◽  
Aerosol Mass ◽  
Photochemical Aging ◽  
Organic Gases

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes is not fully understood. As part of the Fire Influence on Regional and Global Environments Experiment (FIREX 2016), we investigated the effect of photochemical aging on biomass burning organic aerosol (BBOA), with a focus on fuels from the western United States. Emissions were sampled into a small (150 L) environmental chamber and photochemically aged via the addition of ozone and irradiation by 254 nm light. While some fraction of species undergoes photolysis, the vast majority of aging occurs via reaction with OH radicals, with total OH exposures corresponding to the equivalent of up to 10 days of atmospheric oxidation. For all fuels burned, large and rapid changes are seen in the ensemble chemical composition of BBOA, as measured by an aerosol mass spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for all aging experiments and continues to grow with increasing OH exposure, but the magnitude of the SOA formation is highly variable between experiments. This variability can be explained well by a combination of experiment-to-experiment differences in OH exposure and the total concentration of non-methane organic gases (NMOGs) in the chamber before oxidation, measured by PTR-ToF-MS (r2 values from 0.64 to 0.83). From this relationship, we calculate the fraction of carbon from biomass burning NMOGs that is converted to SOA as a function of equivalent atmospheric aging time, with carbon yields ranging from 24 ± 4 % after 6 hours to 56 ± 9 % after 4 days.

scholarly journals Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) – Part 1: Fine particle composition and organic source apportionment

2009 ◽  
Vol 9 (2) ◽  
pp. 8377-8427 ◽  
Author(s):  
A. C. Aiken ◽  
D. Salcedo ◽  
M. J. Cubison ◽  
J. A. Huffman ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
High Resolution ◽  
Mexico City ◽  
Biomass Burning ◽  
Emissions Inventory ◽  
Secondary Sources ◽  
Diurnal Cycles ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Order Of Magnitude ◽  
Primary Emissions

Abstract. Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM2.5 chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM2.5 emissions by a factor of ~4, and it is ~16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is underestimated by at least an order-of-magnitude in the inventory.

scholarly journals Key chemical NO<sub>x</sub> sink uncertainties and how they influence top-down emissions of nitrogen oxides

2013 ◽  
Vol 13 (17) ◽  
pp. 9057-9082 ◽  
Author(s):  
T. Stavrakou ◽  
J.-F. Müller ◽  
K. F. Boersma ◽  
R. J. van der A ◽  
J. Kurokawa ◽  
...  
Keyword(s):  
South Asia ◽  
Transport Model ◽  
Field Studies ◽  
Anthropogenic Source ◽  
Oh Radicals ◽  
Top Down ◽  
Model Calculations ◽  
Tropical Regions ◽  
Recent Developments ◽  
The Impact

Abstract. Triggered by recent developments from laboratory and field studies regarding major NOx sink pathways in the troposphere, this study evaluates the influence of chemical uncertainties in NOx sinks for global NOx distributions calculated by the IMAGESv2 chemistry-transport model, and quantifies their significance for top-down NOx emission estimates. Our study focuses on five key chemical parameters believed to be of primary importance, more specifically, the rate of the reaction of NO2 with OH radicals, the newly identified HNO3-forming channel in the reaction of NO with HO2, the reactive uptake of N2O5 and HO2 by aerosols, and the regeneration of OH in the oxidation of isoprene. Sensitivity simulations are performed to estimate the impact of each source of uncertainty. The model calculations show that, although the NO2+OH reaction is the largest NOx sink globally accounting for ca. 60% of the total sink, the reactions contributing the most to the overall uncertainty are the formation of HNO3 in NO+HO2, leading to NOx column changes exceeding a factor of two over tropical regions, and the uptake of HO2 by aqueous aerosols, in particular over East and South Asia. Emission inversion experiments are carried out using model settings which either minimise (MINLOSS) or maximise (MAXLOSS) the total NOx sink, both constrained by one year of OMI NO2 column data from the DOMINO v2 KNMI algorithm. The choice of the model setup is found to have a major impact on the top-down flux estimates, with 75% higher emissions for MAXLOSS compared to the MINLOSS inversion globally. Even larger departures are found for soil NO (factor of 2) and lightning (1.8). The global anthropogenic source is better constrained (factor of 1.57) than the natural sources, except over South Asia where the combined uncertainty primarily associated to the NO+HO2 reaction in summer and HO2 uptake by aerosol in winter lead to top-down emission differences exceeding a factor of 2. Evaluation of the emission optimisation is performed against independent satellite observations from the SCIAMACHY sensor, with airborne NO2 measurements of the INTEX-A and INTEX-B campaigns, as well as with two new bottom-up inventories of anthropogenic emissions in Asia (REASv2) and China (MEIC). Neither the MINLOSS nor the MAXLOSS setup succeeds in providing the best possible match with all independent datasets. Whereas the minimum sink assumption leads to better agreement with aircraft NO2 profile measurements, consistent with the results of a previous analysis (Henderson et al., 2012), the same assumption leads to unrealistic features in the inferred distribution of emissions over China. Clearly, although our study addresses an important issue which was largely overlooked in previous inversion exercises, and demonstrates the strong influence of NOx loss uncertainties on top-down emission fluxes, additional processes need to be considered which could also influence the inferred source.

scholarly journals Influences of hydroxyl radicals (OH) on top-down estimates of the global and regional methane budgets

2020 ◽  
Author(s):  
Yuanhong Zhao ◽  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Xin Lin ◽  
Antoine Berchet ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Climate Models ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Temporal Variations ◽  
Oh Radicals ◽  
Chemical Transport Model ◽  
Top Down ◽  
Ch4 Emissions ◽  
The Impact

Abstract. The hydroxyl radical (OH), which is the dominant sink of methane (CH4), plays a key role to close the global methane budget. Previous research that assessed the impact of OH changes on the CH4 budget mostly relied on box modeling inversions with a very simplified atmospheric transport and no representation of the heterogeneous spatial distribution of OH radicals. Here using a variational Bayesian inversion framework and a 3D chemical transport model, LMDz, combined with 10 different OH fields derived from chemistry-climate models (CCMI experiment), we evaluate the influence of OH burden, spatial distribution, and temporal variations on the global CH4 budget. The global tropospheric mean CH4-reaction-weighted [OH] ([OH]GM-CH4) ranges 10.3–16.3 × 105 molec cm−3 across 10 OH fields during the early 2000s, resulting in inversion-based global CH4 emissions between 518 and 757 Tg yr−1. The uncertainties in CH4 inversions induced by the different OH fields are comparable to, or even larger than the uncertainty typically given by bottom-up and top-down estimates. Based on the LMDz inversions, we estimate that a 1 %-increase in OH burden leads to an increase of 4 Tg yr−1 in the estimate of global methane emissions, which is about 25 % smaller than what is estimated by box-models. The uncertainties in emissions induced by OH are largest over South America, corresponding to large inter-model differences of [OH] in this region. From the early to the late 2000s, the optimized CH4 emissions increased by 21.9 ± 5.7 Tg yr−1 (16.6–30.0 Tg yr−1), of which ~ 25 % (on average) is contributed by −0.5 to +1.8 % increase in OH burden. If the CCMI models represent the OH trend properly over the 2000s, our results show that a higher increasing trend of CH4 emissions is needed to match the CH4 observations compared to the CH4 emission trend derived using constant OH. This study strengthens the importance to reach a better representation of OH burden and of OH spatial and temporal distributions to reduce the uncertainties on the global CH4 budget.

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

2007 ◽  
Vol 7 (24) ◽  
pp. 6119-6129 ◽  
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.

Climatological Biomass Burning CO – Where it comes from and where it goes.

2020 ◽  
Author(s):  
Nikos Daskalakis ◽  
Maria Kanakidou ◽  
Mihalis Vrekoussis ◽  
Laura Gallardo
Keyword(s):  
Biomass Burning ◽  
Transport Model ◽  
Source Region ◽  
Atmospheric Composition ◽  
Anthropogenic Sources ◽  
3 Dimensional ◽  
Source Regions ◽  
The World ◽  
Transport Patterns ◽  
The Impact

&lt;p&gt;Carbon Monoxide (CO) is an important atmospheric trace gas, and among the key O&lt;sub&gt;3&lt;/sub&gt; precursors in the troposphere, alongside NO&lt;sub&gt;x&lt;/sub&gt; and VOCs. It is among the most important sinks of OH radical in the atmosphere, which controls lifetime of CH&lt;sub&gt;4&lt;/sub&gt; &amp;#8212; a major greenhouse gas. Biomass burning sources contribute about 25% to the global emissions of CO, with the remaining CO being either emitted from anthropogenic sources, or being chemically formed in the atmosphere. Because of CO tropospheric lifetime is about two months; it can be transported in the atmosphere thus its sources have a hemispheric impact on atmospheric composition.&lt;/p&gt;&lt;p&gt;The extent of the impact of biomass burning to remote areas of the world through long range transport is here investigated using the global 3-dimensional chemistry transport model TM4-ECPL. For this, tagged biomass burning CO tracers from the 13 different HTAP (land) source regions are used in the model in order to evaluate the contribution of each source region to the CO concentrations in the 170 HTAP receptor regions that originate from biomass burning. The global simulations cover the period 1994&amp;#8212;2015 in order to derive climatological transport patterns for CO and assess the contribution of each of the source regions to each of the receptor regions in the global troposphere. The CO simulations are evaluated by comparison with satellite observations from MOPITT and ground based observations from WDCGG. We show the significant impact of biomass burning emissions to the most remote regions of the world.&lt;/p&gt;

scholarly journals Organic pollutants from tropical peatland fires: regional influences and its impact on lower stratospheric ozone

2020 ◽  
Author(s):  
Simon Rosanka ◽  
Bruno Franco ◽  
Lieven Clarisse ◽  
Pierre-François Coheur ◽  
Andreas Wahner ◽  
...  
Keyword(s):  
Biomass Burning ◽  
El Niño ◽  
El Nino ◽  
Stratospheric Ozone ◽  
Lower Troposphere ◽  
Atmospheric Model ◽  
Chemical Production ◽  
Global Models ◽  
Upward Transport ◽  
The Impact

Abstract. The particularly strong dry season in Indonesia in 2015, caused by an exceptional strong El Niño, led to severe peatland fires resulting in high volatile organic compound (VOC) biomass burning emissions. At the same time, the developing Asian monsoon anticyclone (ASMA) and the general upward transport in the intertropical convergence zone (ITCZ) efficiently transported the resulting primary and secondary pollutants to the upper troposphere/lower stratosphere (UTLS). In this study, we assess the importance of these VOC emissions for the composition of the lower troposphere and the UTLS, and we investigate the effect of in-cloud oxygenated VOC (OVOC) oxidation during such a strong pollution event. This is achieved by performing multiple chemistry simulations using the global atmospheric model ECHAM/MESSy (EMAC). By comparing modelled columns of the biomass burning marker hydrogen cyanide (HCN) to spaceborne measurements from the Infrared Atmospheric Sounding Interferometer (IASI), we find that EMAC properly captures the exceptional strength of the Indonesian fires. In the lower troposphere, the increase in VOC levels is higher in Indonesia compared to other biomass burning regions. This has a direct impact on the oxidation capacity, resulting in the largest regional reduction in hydroxyl radicals (OH) and nitrogen oxides (NOx). Even though an increase in ozone (O3) is predicted close to the peatland fires, particular high concentrations of phenols lead to an O3 depletion in eastern Indonesia. By employing the detailed in-cloud OVOC oxidation scheme Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC), we find that the predicted changes are dampened and that by ignoring these processes, global models tend to overestimate the impact of such extreme pollution events. In the ASMA and the ITCZ, the upward transport leads to elevated VOC concentrations in the UTLS region, which results in a depletion of lower stratospheric O3. We find that this is caused by a high destruction of O3 by phenoxy radicals and by the increased formation of NOx reservoir species, which dampen the chemical production of O3. The Indonesian peatland fires regularly occur during El Niño years and contribute to the depletion of O3. In the time period from 2001 to 2016, we find that the lower stratospheric O3 is reduced by about 0.38 DU and contributes to about 25 % to the lower stratospheric O3 reduction observed by remote sensing. By not considering these processes, global models might not be able to reproduce this variability in lower stratospheric O3.

Analysis of the impact of biomass burning emissions on global ozone production in the upper troposphere with MOCAGE CTM and IAGOS airborne data.

2020 ◽  
Author(s):  
Martin Cussac ◽  
Virginie Marécal ◽  
Valérie Thouret ◽  
Béatrice Josse
Keyword(s):  
Significant Role ◽  
Biomass Burning ◽  
Transport Model ◽  
Chemical Species ◽  
Ozone Production ◽  
In Situ Observation ◽  
Transport Pathway ◽  
Upper Troposphere ◽  
The Impact

&lt;p&gt;The UTLS (Upper Troposphere/Lower Stratosphere) is a key layer of the atmosphere as its chemical composition impacts both the troposphere and the stratosphere, and therefore plays a significant role in the climate system. Ozone at this altitude for instance plays a great role on surface temperature. Unlike in the stratosphere; it can be produced from the photolysis of precursors originating in the troposphere; mainly nitrous oxides (NO&lt;sub&gt;x&lt;/sub&gt;) and carbon monoxide (CO) at this pressure range. Biomass burning emissions in particular are likely to play a significant role in the quantities of these species in the upper troposphere and thus impacting ozone balance. This effect is investigated thanks to the global chemistry transport model MOCAGE. Because of the strong vertical gradients in this layer of the atmosphere, well resolved in-situ observation dataset are valuable for model evaluation. As of measurements used to validate MOCAGE results, IAGOS in-situ measurements from equipped commercial aircraft were chosen for their fine vertical resolution as well as their wide geographical coverage. Using both of these tools, upper tropospheric air composition is studied, with a focus on ozone precursors and production linked to biomass burning emissions.&lt;/p&gt;&lt;p&gt;Firstly is investigated the direct impact of biomass burning emissions on CO concentration in the upper troposphere, as it is both a good tracer of wildfire plumes in the atmosphere and it plays a role in the upper troposphere chemical balance. For this purpose MOCAGE simulations spaning over the year of 2013 where biomass burning emissions were turned on and off are compared to estimate a contribution to upper tropospheric CO. These simulations were validated using all the available data from the IAGOS database. It was found that biomass burning impacted CO levels globally, with the strongest enhancement happening above the most emitting areas (equatorial Africa and the Boreal forests). The importance of a fast vertical transport pathway above the fires was also highlighted with the possible occurrence of pyroconvection in addition to deep convection. Secondly, other chemical species related to ozone production were looked upon. Peroxyacetyl Nitrates (PAN) for instance were found to be impacted by biomass burning as it is a product of NOx oxidation as well as the main &quot;reservoir&quot; specie for NOx in the upper troposphere. Ultimately, ozone production resulting from biomass burning emissions is investigated, both in biomass burning plumes encountered by IAGOS aircraft, and on a more global scale using the MOCAGE simulations.&lt;/p&gt;

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