1. Atmospheric peroxyacetyl nitrate (PAN) : a global budget and source attributionE. V. Fischer, D. J. Jacob, R. M. Yantosca, M. P. Sulprizio, D. B. Millet, Jiandong Mao, F. Paulot, H. B. Singh, A. Roiger, Katja Džepina, 2014, original scientific article Abstract: Peroxyacetyl nitrate (PAN) formed in the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs) is the principal tropospheric reservoir for nitrogen oxide radicals (NOx = NO + NO2). PAN enables the transport and release of NOx to the remote troposphere with major implications for the global distributions of ozone and OH, the main tropospheric oxidants. Simulation of PAN is a challenge for global models because of the dependence
of PAN on vertical transport as well as complex and uncertain NMVOC sources and chemistry. Here we use an improved representation of NMVOCs in a global 3-D chemical
transport model (GEOS-Chem) and show that it can simulate PAN observations from aircraft campaigns worldwide.
The immediate carbonyl precursors for PAN formation include acetaldehyde (44 % of the global source), methylglyoxal (30 %), acetone (7 %), and a suite of other isoprene and
terpene oxidation products (19 %). A diversity of NMVOC
emissions is responsible for PAN formation globally including isoprene (37 %) and alkanes (14 %). Anthropogenic
sources are dominant in the extratropical Northern Hemisphere outside the growing season. Open fires appear to play
little role except at high northern latitudes in spring, although
results are very sensitive to plume chemistry and plume rise.
Lightning NOx is the dominant contributor to the observed
PAN maximum in the free troposphere over the South Atlantic. Keywords: peroxyacetyl nitrate, non-methane volatile organic compounds, global 3-D chemical transport model, GEOS-chem Published in RUNG: 11.04.2021; Views: 2372; Downloads: 0 This document has many files! More... |
2. Substantial brown carbon emissions from wintertime residential wood burning over FranceYunjiang Zhang, Alexandre Albinet, Jean-Eudes Petit, Véronique Jacob, Florie Chevrier, Gregory Gille, Sabrina Pontet, Eve Chrétien, Marta Dominik-Sègue, Gilles Levigoureux, Griša Močnik, Valérie Gros, Jean-Luc Jaffrezo, Olivier Favez, 2020, original scientific article Abstract: Brown carbon (BrC) is known to absorb light at subvisible wavelengths but its optical properties and sources are still poorly documented, leading to large uncertainties in climate studies. Here, we show its major wintertime contribution to total aerosol absorption at 370 nm (18–42%) at 9 different French sites. Moreover, an excellent correlation with levoglucosan (r2 = 0.9 and slope = 22.2 at 370 nm), suggesting important contribution of wood burning emissions to ambient BrC aerosols in France. At all sites, BrC peaks were mainly observed during late evening, linking to local intense residential wood burning during this time period. Furthermore, the geographic origin analysis also highlighted the high potential contribution of local and/or small-regional emissions to BrC. Focusing on the Paris region, twice higher BrC mass absorption efficiency value was obtained for less oxidized biomass burning organic aerosols (BBOA) compared to more oxidized BBOA (e.g., about 4.9 ± 0.2 vs. 2.0 ± 0.1 m2 g−1, respectively, at 370 nm). Finally, the BBOA direct radiative effect was found to be 40% higher when these two BBOA fractions are treated as light-absorbing species, compared to the non-absorbing BBOA scenario. Keywords: Brown carbon, Multi sites, Residential wood burning, Mass absorption efficiency, France Published in RUNG: 20.07.2020; Views: 3075; Downloads: 0 This document has many files! More... |
3. Pipistrel Taurus G4 : on creation and evaluation of the winning aeroplane of NASA Green Flight Challenge 2011Gregor Veble, Jure Tomažič, Tine Tomažič, Vid Plevnik, Franc Popit, Sašo Kolar, Rado Kikelj, Jacob W. Langelaan, Kirk Miles, 2011, original scientific article Keywords: električna letala, konstrukcija, učinkovitost, modeliranje zmogljivosti, poskusi letenja Published in RUNG: 10.07.2015; Views: 5429; Downloads: 29 Link to full text |