Fraunhofer-Institut für Atmosphärische Umweltforschung IFU

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  • Publication
    Biogenic and anthropogenic fluxes of non-methane hydrocarbons over an urban-impacted forest, Frankfurter Stadtwald, Germany
    ( 2000)
    Steinbrecher, R.
    ;
    Klauer, M.
    ;
    Hauff, K.
    ;
    Stockwell, W.R.
    ;
    Jaeschke, W.
    ;
    Dietrich, T.
    ;
    Herbert, F.
    In an urban-impacted oak/beech/pine forest (Frankfurter Stadtwald, 50° 04' 06" N; 8° 40' 17" E) trace gas distributions and fluxes of anthropogenic and biogenic non-methane hydrocarbons (NMHC) were determined for a bright weather period in August 1995. In general, ozone peaked at 70 ppb in the early afternoon. NO and NO sub x reach values of up to 25 ppb under low wind conditions and local automobile traffic. Anthropogenic NMHC dominate with up to 8.0 ppb in the air above the forest. The dominating biogenic NMHC in ambient air above the forest was isoprene with peak values of 1.5 ppb during daytime. The flux-gradient relationship with specific adapted and validated stability functions for this forest was used for calculating NMHC-fluxes. Transfer times of up to 100 s require a correction of the mixing ratios for HO-radical chemistry occurring along the gradient between 22 and 51 m for high reactive substances such as isoprene. The specific situation in the Frankfurter Stadtwald with high road traffic inside the forest (up to 10,000 vehicles per hour) lead to sometimes significant emission of anthropogenic NMHC as exhaust plumes were spread in the trunk space. Isoprene fluxes were high and amounted to 3.5 nmol m high -2 ground area s high -1 due to the high percentage of oaks growing in the forest but were at the lower end of estimates made by current biogenic NMHC emission inventories. The high isoprene emission flux and ambient air mixing ratios underscore the importance of isoprene daytime and nighttime chemistry for the Frankfurt area.
  • Publication
    Modeling speciated terpenoid emissions from the European boreal forest
    ( 2000)
    Lindfors, V.
    ;
    Laurila, T.
    ;
    Hakola, H.
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    Steinbrecher, R.
    ;
    Rinne, J.
    We present the first estimates of speciated monoterpene emissions from the North European coniferous forests. Measured emission factors and emission profiles of boreal tree species (Picea abies, Pinus sylvestris, Betula pendula, Salix phylicifolia, Populus tremula, and Alnus incana) were used together with detailed satellite land cover information and meteorological data in an emission model based on the Guenther emission algorithms. The variation of the coniferous biomass within the boreal region (60°N to 70°N) was obtained from forest inventory data, and the seasonal variability of the deciduous biomass was taken into account through simple boreal climatology parameterisation. The annual biogenic emissions in the boreal zone are dominated by coniferous species, but in the summer months, the deciduous contribution to the monoterpene and isoprene emissions is considerable. Norway spruce (Picea abies) is the most important isoprene emitter in the north European boreal forests. The biogenic emission fluxes in the South boreal zone are approximately twice as high as fluxes in the North boreal zone. alpha- and ß-pinene, carene, and cineole are the most abundant emitted terpenes, with a strong contribution of isoprene and linalool during the summer months.
  • Publication
    An overview of the castelporziano experiments
    ( 1997)
    Seufert, G.
    ;
    Bartzis, J.
    ;
    Bomboi, T.
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    Ciccioli, P.
    ;
    Cieslik, S.
    ;
    Dlugi, R.
    ;
    Foster, P.
    ;
    Hewitt, C.N.
    ;
    Kesselmeier, J.
    ;
    Kotzias, D.
    ;
    Lenz, R.
    ;
    Manes, F.
    ;
    Perez Pastor, R.
    ;
    Steinbrecher, R.
    ;
    Torres, L.
    ;
    Valentini, R.
    ;
    Versino, B.
    This paper reviews the major outcomes of the measuring campaigns performed at the Castelporziano nature preserve near Rome, Italy, by 14 European laboratories as part of the BEMA (Biogenic Emissions in the Mediterranean Area)-project. Six campaigns of 1-4 weeks duration were carried out in different seasons of the years 1993-1994 at semi-continuously running test plots in the nature reserve, representing common Mediterranean vegetation types. The aim was to characterise, at the different test plots, the atmospheric chemical and meteorological situations, the plant biomass and physiology, the type, amount and controls of emissions from different plants by means of branch enclosures, and the BVOC emission fluxes from different ecosystems, by scaling up enclosure data from individual sources, and by measuring fluxes directly by use of micrometeorological methods. An important focus during the initial phase of the five year BEMA-project was the harmonisation and improvement of the analytic al, physiological and micrometeorological methods used, and the development and testing of new methods for measuring BVOC fluxes.
  • Publication
    Sampling and analysis of terpenes in air. An interlaboratory comparison
    ( 1997)
    Larsen, B.
    ;
    Bomboi-Mingarro, T.
    ;
    Brancaleoni, E.
    ;
    Calogirou, A.
    ;
    Cecinato, A.
    ;
    Coeur, C.
    ;
    Chatzianestis, I.
    ;
    Duane, M.
    ;
    Frattoni, M.
    ;
    Fugit, J.-L.
    ;
    Hansen, U.
    ;
    Jacob, V.
    ;
    Mimikos, N.
    ;
    Hoffmann, T.
    ;
    Owen, S.
    ;
    Perez Pastor, R.
    ;
    Reichmann, A.
    ;
    Seufert, G.
    ;
    Staudt, M.
    ;
    Steinbrecher, R.
    An interlaboratory comparison on the sampling and analysis of terpenes in air was held within the framework of the BEMA (Biogenic Emissions in the Mediterranean Area) project in May 1995. Samples were drawn and analysed by 10 European laboratories from a dynamic artificial air generator in which five terpenes were present at low ng litre(-1) levels and ozone varied between 8 and 125 ppbv. Significant improvements over previous inter-comparison exercises in the quality of results were observed. At the ozone mixing ratio of 8 ppbv a good agreement among laboratories was obtained for all test compounds with mean values close to the target concentration. At higher mixing ratios, ozone reduced terpene recoveries and decreased the precision of the measurements due to ozonolysis during sampling. For beta-pinene this effect was negligible but for the more reactive compounds significant losses were observed in some laboratories (cis-beta-ocimene = trans-beta-ocimene > linalool > d-limonene). Th e detrimental effect of ozone was significantly lower for the laboratories which removed ozone prior to sampling by scrubbers. Parallel sampling was carried out with a standardised sampler and each individual laboratory's own device. A good agreement between the two sets of results was obtained, clearly showing that the majority of laboratories used efficient sampling systems. Two different standard solutions were analysed by each laboratory. Only in a few cases did interference in the GC separation cause problems for the quantification of the terpenes (nonanal/linalool). However, making up of standards for the calibration of the analytical equipment (GC-MS or GC-FID) was pointed out as a source of error in some laboratories.
  • Publication
    Ambient atmospheric trace gas concentrations and meteorological parameters during the first BEMA measuring campaign on may 1994 at Castelporziano, Italy
    ( 1997)
    Kalabokas, P.
    ;
    Bartzis, J.G.
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    Bomboi, T.
    ;
    Ciccioli, P.
    ;
    Cieslik, S.
    ;
    Dlugi, R.
    ;
    Foster, P.
    ;
    Kotzias, D.
    ;
    Steinbrecher, R.
    During the first measuring campaign of the BEMA project, carried out in May 1994 at Castelporziano, near Rome, Italy, one of the tasks was to measure continuously meteorological parameters and tropospheric trace gas concentrations. The atmospheric species measured were ozone, NOx anthropogenic and biogenic hydrocarbons, carbonyl compounds, hydrogen peroxide, organic peroxides and PAN. Another goal was the characterization of the atmospheric circulation patterns. The results showed that anthropogenic pollution is present at the Castelporziano site originating mainly from the Rome metropolitan area but also from other directions. The average concentration levels of NOx were about 9 ppb, the average total measured anthropogenic hydrocarbon concentration was 67 ppbC and the average ozone mixing ratio was 36 ppb. The possible role of naturally emitted VOCs in tropospheric ozone formation is discussed.
  • Publication
    Isoprenoid emission of oak species typical for the mediterranean area. Source strength and controlling variables
    ( 1997)
    Steinbrecher, R.
    ;
    Hauff, K.
    ;
    Rabong, R.
    ;
    Steinbrecher, J.
    Measurements of isoprenoid emission on five Mediterranean oak species in the field revealed that Quercus frainetto, Quercus petraea and Quercus pubescens are strong emitters of isoprene. In contrast Quercus cerris and Quercus suber emitted no significant amounts of isoprene and monoterpenes. For Q. pubenscens and Q. frainetto median emission factors of 16.68 nmolm(-2) s(-1) (86.06 my g g(-1) dwh(-1)) and 30.72 nmolm(-2) s(-1) (133.95 my g g(-1) dwh(-1)) were calculated, respectively. The 25 to 75 percentiles span of the emission factor data sets ranged from - 53 per cent to + 56 per cent of the median values. Light and temperature are the main controlling factors for isoprene emission. The influence of other environmental and plant physiological parameters on the isoprene emission is discussed. The "Guenther" emission algorithm is able to predict the daily maximum of the isoprene emission within the plant specific uncertainty range. However, the morning increase and the afternoon drop in the isoprene emission is not well parameterized. On the basis of process oriented models for the synthesis of isoprene in plants, a further reduction in the uncertainty may be achieved resulting in a more reliable prediction of short-time variation in isoprene emission.
  • Publication
    Biogenic emission from the mediterranean pseudosteppe ecosystem present in Castelporziano
    ( 1997)
    Ciccioli, P.
    ;
    Fabozzi, C.
    ;
    Brancaleoni, E.
    ;
    Cecinato, A.
    ;
    Frattoni, M.
    ;
    Cieslik, S.
    ;
    Kotzias, D.
    ;
    Seufert, G.
    ;
    Foster, P.
    ;
    Steinbrecher, R.
    Emission rates and fluxes of biogenic components emitted by a Mediterranean Pseudosteppe were measured in the BEMA test site of Castelporziano during the 1993 and 1994 field campaigns. Enclosure and micrometeorological techniques were used. Although the emission was comprised of isoprene, semi-volatile aldehydes, acetic acid and monoterpenes at trace levels, the most relevant compound in air was isoprene. Basal emission rates for isoprene (normalized at 30 deg C and 1000 myE PAR) as defined by Guenther et al. (1991, J. geophys. Res. 96, 10,799-10,808) were obtained for this ecosystem by combining experimental observations and predictions based on the Guenther algorithm. It is shown that the Mediterranean Pseudosteppe is a strong isoprene emitter with a basal emission rate of 0.45 my g m (-2) s (-1) during the flowering season. At the end of the maximum physiologically active season basal emission rate ranged only in 0.1-0.15my g m(-2) s(-1). A close dependence from light and temperatur e for the isoprene emission is observed. The decline in emission rates seems to be associated with a reduction in photosynthetic activity linked to senescence of the vegetation present in this ecosystem. The results obtained indicate that the Mediterranean Pseudosteppe is an ecosystem characterized by a rapid and strong variability in isoprene emission. It represents a source of isoprene comparable to deciduous forest areas only during the flowering season (from the middle of March to the middle of May) whereas it becomes a minor source during the end of the maximum physiologically active season.
  • Publication
    Monoterpenes in air samples. European intercomparison experiments
    ( 1994)
    Steinbrecher, R.
    ;
    Eichstädter, G.
    ;
    Schürmann, W.
    ;
    Torres, L.
    ;
    Clement, B.
    ;
    Simon, V.
    ;
    Kotzias, D.
    ;
    Daiber, R.
    ;
    Eijk, J. van
  • Publication
    Biosphere/atmosphere interactions: integrated research in an European coniferous forest ecosystem
    ( 1992)
    Enders, G.
    ;
    Dlugi, R.
    ;
    Steinbrecher, R.
    ;
    Clement, B.
    ;
    Daiber, R.
    ;
    Eijk, V.J.
    ;
    Gäb, S.
    ;
    Haziza, M.
    ;
    Helas, G.
    ;
    Herrman, U.
    ;
    Kessel, M.
    ;
    Kesselmeier, J.
    ;
    Kotzias, D.
    ;
    Kourtidis, K.
    ;
    Kurth, H.-H.
    ;
    McMillen, R.T.
    ;
    Roider, G.
    ;
    Schürmann, W.
    ;
    Torres, L.
    For the determination of regionally averaged fluxes and budgets of atmospheric trace constituents, the ultimate goal of the European Environment Research EUROTRAC, several ecosystems must be investigated, each representative of larger areas. One of the most wide-spread vegetation type is the coniferous forest, in which several compartments exist such as soil, trunk space, canopy and 'free' atmosphere above, which differ considerably in biology, chemistry and meteorology, but increase strongly by feedback processes caused by turbulent mixing and chemical reactions. To understand forest/atmosphere relations in detail, measurements are needed which provide concentrations, emission and deposition data of various chemical compounds as well as micrometeorological quantities. These measurements have to be carried out simultaneously in all storeys of a forest over extended periods and must be highly resolved with respect to time and space. In a first step detailed small-scale studies must be performed. This paper describes the scientific approach for integrated multi-disciplinary studies at Schachtenau, a research site in Central Europe's largest continuous forest, and presents first results from joint experiments.