Global Modeling of the Oceanic Source of Organic Aerosols

Myriokefalitakis, Stelios; Vignati, E.; Tsigaridis, Kostas; Papadimas, C. D.; Sciare, Jean; Mihalopoulos, Nikolaos; Facchini, M. C.; Rinaldi, Matteo; Dentener, Frank; Čeburnis, Darius; Hatzianastasiou, Nikos; O’Dowd, Colin; Weele, M. van; Kanakidou, Maria

doi:10.1155/2010/939171

Cited by 122 publications

(134 citation statements)

References 76 publications

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“…Although high phytoplankton activity in the surface ocean can emit a certain amount of isoprene and other BVOCs, their levels are rather minor compared to emissions from terrestrial plants. 9,10,53 Here, the NAQPMS model results demonstrated that at Mumbai, SOA loadings were lower in June 2006 (about 0.6 μg m −3 ) than those in February 2007 (1.5 μg m −3 ). The GEOS-Chem model results again showed that SOA loadings were much lower (about 0.072 μg m −3 ) in summer than those (0.51 μg m −3 ) in winter.…”

Section: ■ Materials and Methodsmentioning

confidence: 68%

Molecular markers of biomass burning, fungal spores and biogenic SOA in the Taklimakan desert aerosols

Zhuang

Sun

et al. 2016

Atmospheric Environment

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Biogenic secondary organic aerosols (SOA) are generally considered to be more abundant in summer than in winter. Here, polar organic marker compounds in urban background aerosols from Mumbai were measured using gas chromatography−mass spectrometry. Surprisingly, we found that concentrations of biogenic SOA tracers at Mumbai were several times lower in summer (8−14 June 2006; wet season; n = 14) than in winter (13−18 February 2007; dry season; n = 10). Although samples from less than 10% of the season are extrapolated to the full season, such seasonality may be explained by the predominance of the southwest summer monsoon, which brings clean marine air masses to Mumbai. While heavy rains are an important contributor to aerosol removal during the monsoon season, meteorological data (relative humidity and T) suggest no heavy rains occurred during our sampling period. However, in winter, high levels of SOA and their day/night differences suggest significant contributions of continental aerosols through long-range transport together with local sources. The winter/summer pattern of SOA loadings was further supported by results from chemical transport models (NAQPMS and GEOS-Chem). Furthermore, our study suggests that monoterpene-and sesquiterpene-derived secondary organic carbon (SOC) were more significant than those of isoprene-and toluene-SOC at Mumbai.

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Section: ■ Materials and Methodsmentioning

confidence: 68%

Molecular markers of biomass burning, fungal spores and biogenic SOA in the Taklimakan desert aerosols

Zhuang

Sun

et al. 2016

Atmospheric Environment

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“…The emission of alkyl nitrates from the ocean has been linked to both the concentration of chlorophyll and sea temperature (Chuck et al, 2002;Dahl and Saltzman, 2008). A strong seasonality exists in the chlorophyll concentrations in the SH (Myriokefalitakis et al, 2010) resulting in maximal concentrations occurring during the boreal wintertime; therefore any resulting emission flux is likely to exhibit a similar seasonality. The small emission of CH 3 ONO 2 measured from biomass and savannah fires (∼ 18 Gg yr −1 , Simpson et al, 2002) is an order of magnitude lower than the ocean emission flux and thus is not included.…”

Section: Definition Of the Emission Scenarios And Sensitivity Studiesmentioning

confidence: 99%

“…As we do not apply either a diurnal or seasonal variation in the emission term, the model cannot be expected to be able to capture exactly the same profile. To improve on this, future studies could exploit chlorophyll maps from satellites such as MODIS as demonstrated by Myriokefalitakis et al (2010) for marine organic aerosol formation. However, our study is more focussed on the influence of the chemical production term therefore we consider developing such an approach to be beyond the scope of this present study.…”

Section: Comparisons Against Surface and Aircraft Measurementsmentioning

confidence: 99%

The impact of the chemical production of methyl nitrate from the NO + CH<sub>3</sub>O<sub>2</sub> reaction on the global distributions of alkyl nitrates, nitrogen oxides and tropospheric ozone: a global modelling study

et al. 2014

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Abstract. The formation, abundance and distribution of organic nitrates are relevant for determining the production efficiency and resident mixing ratios of tropospheric ozone (O 3 ) on both regional and global scales. Here we investigate the effect of applying the recently measured direct chemical production of methyl nitrate (CH 3 ONO 2 ) during NO x recycling involving the methyl-peroxy radical on the global tropospheric distribution of CH 3 ONO 2 and the perturbations introduced towards tropospheric NO x and O 3 using the TM5 global chemistry transport model. By comparisons against numerous observations, we show that the global surface distribution of CH 3 ONO 2 can be largely explained by introducing the chemical production mechanism using a branching ratio of 0.3 %, when assuming a direct oceanic emission source of ∼ 0.15 Tg N yr −1 . On a global scale, the chemical production of CH 3 ONO 2 converts 1 Tg N yr −1 from nitrogen oxide for this branching ratio. The resident mixing ratios of CH 3 ONO 2 are found to be highly sensitive to the dry deposition velocity that is prescribed, where more than 50 % of the direct oceanic emission is lost near the source regions, thereby mitigating the subsequent effects due to long-range and convective transport out of the source region. For the higher alkyl nitrates (RONO 2 ) we find improvements in the simulated distribution near the surface in the tropics (10 • S-10 • N) when introducing direct oceanic emissions equal to ∼ 0.17 Tg N yr −1 . In terms of the vertical profile of CH 3 ONO 2 , there are persistent overestimations in the free troposphere and underestimations in the upper troposphere across a wide range of latitudes and longitudes when compared against data from measurement campaigns. This suggests either a missing transport pathway or source/sink term, although measurements show significant variability in resident mixing ratios at high altitudes at global scale. For the vertical profile of RONO 2 , TM5 performs better at tropical latitudes than at mid-latitudes, with similar features in the comparisons to those for CH 3 ONO 2 . Comparisons of CH 3 ONO 2 with a wide range of surface measurements shows that further constraints are necessary regarding the variability in the deposition terms for different land surfaces in order to improve on the comparisons presented here. For total reactive nitrogen (NO y ) ∼ 20 % originates from alkyl nitrates in the tropics and subtropics, where the introduction of both direct oceanic emissions and the chemical formation mechanism of CH 3 ONO 2 only makes a ∼ 5 % contribution to the total alkyl nitrate content in the upper troposphere when compared with aircraft observations. We find that the increases in tropospheric O 3 that occur due oxidation of CH 3 ONO 2 originating from direct oceanic emission is negated when accounting for the chemical formation of CH 3 ONO 2 , meaning that the impact of such oceanic emissions on atmospheric lifetimes becomes marginal when a branching ratio of 0.3 % is adopted.

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“…Recent estimates of OM from marine sources range between 2.3 to 75 TgC yr −1 Roelofs, 2008;Gantt et al, 2009;Ito and Kawamiya, 2010;Myriokefalitakis et al, 2010;Long et al, 2011;Vignati et al, 2010). This wide range reflects challenges and large uncertainties associated with quantifying these emissions, as well as differences in treatment (including both sub-micron and super-micron size ranges or primary and secondary sources).…”

Section: K Lapina Et Al: Marine Aerosol Backgroundmentioning

confidence: 99%

Investigating organic aerosol loading in the remote marine environment

et al. 2011

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Abstract. Aerosol loading in the marine environment is investigated using aerosol composition measurements from several research ship campaigns (ICEALOT, MAP, RHaMBLe, VOCALS and OOMPH), observations of total AOD column from satellite (MODIS) and ship-based instruments (Maritime Aerosol Network, MAN), and a global chemical transport model (GEOS-Chem). This work represents the most comprehensive evaluation of oceanic OM emission inventories to date, by employing aerosol composition measurements obtained from campaigns with wide spatial and temporal coverage. The model underestimates AOD over the remote ocean on average by 0.02 (21 %), compared to satellite observations, but provides an unbiased simulation of ground-based Maritime Aerosol Network (MAN) observations. Comparison with cruise data demonstrates that the GEOS-Chem simulation of marine sulfate, with the mean observed values ranging between 0.22 µg m −3 and 1.34 µg m −3 , is generally unbiased, however surface organic matter (OM) concentrations, with the mean observed concentrations between 0.07 µg m −3 and 0.77 µg m −3 , are underestimated by a factor of 2-5 for the standard model run. Addition of a sub-micron marine OM source of approximately 9 TgC yr −1 brings the model into agreement with the ship-based measurements, however this additional OM source does not exCorrespondence to: K. Lapina (klapina@atmos.colostate.edu) plain the model underestimate of marine AOD. The model underestimate of marine AOD is therefore likely the result of a combination of satellite retrieval bias and a missing marine aerosol source (which exhibits a different spatial pattern than existing aerosol in the model).

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Global Modeling of the Oceanic Source of Organic Aerosols

Cited by 122 publications

References 76 publications

Molecular markers of biomass burning, fungal spores and biogenic SOA in the Taklimakan desert aerosols

Molecular markers of biomass burning, fungal spores and biogenic SOA in the Taklimakan desert aerosols

The impact of the chemical production of methyl nitrate from the NO + CH<sub>3</sub>O<sub>2</sub> reaction on the global distributions of alkyl nitrates, nitrogen oxides and tropospheric ozone: a global modelling study

Investigating organic aerosol loading in the remote marine environment

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Global Modeling of the Oceanic Source of Organic Aerosols

Cited by 122 publications

References 76 publications

Molecular markers of biomass burning, fungal spores and biogenic SOA in the Taklimakan desert aerosols

Molecular markers of biomass burning, fungal spores and biogenic SOA in the Taklimakan desert aerosols

The impact of the chemical production of methyl nitrate from the NO + CH&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; reaction on the global distributions of alkyl nitrates, nitrogen oxides and tropospheric ozone: a global modelling study

Investigating organic aerosol loading in the remote marine environment

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The impact of the chemical production of methyl nitrate from the NO + CH<sub>3</sub>O<sub>2</sub> reaction on the global distributions of alkyl nitrates, nitrogen oxides and tropospheric ozone: a global modelling study