Fraunhofer-Institut für Atmosphärische Umweltforschung IFU

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  • Publication
    Airborne measurements of nucleation mode particles I: Coastal nucleation and growth rates
    ( 2007)
    O'Dowd, C.D.
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    Yoon, Y.J.
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    Junkerman, W.
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    Aalto, P.
    ;
    Kulmala, M.
    ;
    Lihavainen, H.
    ;
    Viisanen, Y.
    A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3-5.4-9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of Ireland, in the vicinity of Mace Head. The objective of the exercise was to provide high resolution micro-physical measurements of the coastal nucleation mode in order to map the spatial extent of new particle production regions and to evaluate the evolution, and associated growth rates of the coastal nucleationmode aerosol plume. Results indicate that coastal new particle production is occurring over most areas along the landsea interface with peak concentrations at the coastal plume-head in excess of 106 cm-3. Pseudo-Lagrangian studies of the coastal plume evolution illustrated significant growth of new particles to sizes in excess of 8 nm approximately 10 km downwind of the source region. Close to the plume head (<1km) growth rates can be as high as 123-171 nm h-1, de creasing gradually to 53-72 nm h-1 at 3km. Further along the plume, at distances up to 10km, the growth rates are calculated to be 17-32 nm h-1. Growth rates of this magnitude suggest that after a couple of hours, coastal nucleation mode particles can reach significant sizes where they can contribution to the regional aerosol loading.
  • Publication
    Multipass open-path Fourier-transform infrared measurements for nonintrusive monitoring of gas turbine exhaust composition
    ( 2005)
    Schafer, K.
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    Brockmann, K.
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    Heland, J.
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    Wiesen, P.
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    Jahn, C.
    ;
    Legras, O.
    The detection limits for NO and NO2 in turbine exhausts by nonintrusive monitoring have to be improved. Multipass mode Fourier-transform infrared (FTIR) absorption spectrometry and use of a White mirror system were found from a sensitivity study with spectra simulations in the mid-infrared to be essential for the retrieval of NO2 abundances. A new White mirror system with a parallel infrared beam was developed and tested successfully with a commercial FTIR spectrometer in different turbine test beds. The minimum detection limits for a typical turbine plume of 50 cm in diameter are approximately 6 parts per million (ppm) for NO and 9 ppm for NO2 (as well 100 ppm for CO2 and 4 ppm for CO).
  • Publication
    Factors and processes controlling the concentration of the cosmogenic radionuclide 7Be at high-altitude Alpine stations
    ( 2005)
    Gerasopoulos, E.
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    Zanis, P.
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    Zerefos, C.S.
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    Papastefanou, C.
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    Ringer, W.
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    Gäggeler, H.W.
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    Tobler, L.
    ;
    Kanter, H.J.
  • Patent
    Vorrichtung zur Messung eines Spektrums
    ( 2003)
    Misslbeck, M.
    ;
    Seckmayer, G.
    ;
    Thiel, S.
    Es wird eine Vorrichtung zur Messung eines Spektrums einer Strahlung, insbesondere im UV-Bereich, vorgeschlagen, das einen Eingangsspalt, eine Anordnung zum Aufspalten der einfallenden Strahlung in ein Spektrum und Abbilden des Eingangsspaltes auf eine erste Fokalebene nach Wellenlaengen getrennt aufweist. Eine erste Empfaengeranordnung ist zeilenfoermig in der ersten Fokalebene vorgesehen und erfasst einen ersten Wellenlaengenbereich. Weiterhin ist der ersten Fokalebene eine Oeffnung und hinter der eine zweite Anordnung zum Aufspalten der durch die Oeffnung gelangenden Strahlung in ein zweites Spektrum und Abbilden der Oeffnung der ersten Fokalebene in eine zweite Fokalebene vorgesehen. Eine zweite Empfaengeranordnung in der zweiten Fokalebene erfasst somit einen zweiten Wellenlaengenbereich selektiv.
  • Patent
    Verfahren zur Ermittlung der Nitrifikations- und/oder Denitrifikationsrate von Boeden und Vorrichtung hierzu
    ( 2003)
    Butterbach-Bahl, K.
    DE 19906872 A UPAB: 20001023 NOVELTY - Determining soil nitrification and denitrification rates comprising introducing a soil sample into a gas- and pressure-tight vessel to leave a gas space above the soil, hermetically sealing the vessel, and measuring the pressure, and oxygen (O2) and carbon dioxide (CO2) concentrations at least at the start and end of an incubation period of 0.5-24 hours, is new. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for apparatus for carrying out the novel method, comprising a sealable gas-tight vessel having at least one pressure sensor access port and at least one sealable inlet. USE - For determining soil nitrification and denitrification rates using a complex set of equations given in the specification. ADVANTAGE - The method is simple and inexpensive.
  • Publication
    Determination of anthropogenic emission ratios in the Augsburg area from concentration ratios results from long-term measurements
    ( 2002)
    Klemp, D.
    ;
    Mannschreck, K.
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    Patz, H.W.
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    Habram, M.
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    Matuska, P.
    ;
    Slemr, F.
  • Publication
    Metabolism of reduced and inorganic sulphur in pea cotyledons and distribution into developing seedlings
    ( 2002)
    Herschbach, C.
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    Pilch, B.
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    Tausz, M.
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    Rennenberg, H.
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    Grill, D.
    Sulphur export and redistribution from the cotyledons of pea (Pisum sativum) seedlings was investigated to determine the role of cotyledons as a sulphur source during root-shoot axis development. Thiols and sulphate were analysed using standard biochemical techniques, and S-35 fed to cotyledons by injection. After S-35-cysteine injection, c. 50% of the labelled S in the cotyledon was metabolized to S-35-sulphate. This reaction was partly inhibited by aminooxyacetic acid, an inhibitor of cysteine-desulfhydrase. After S-35-sulphate application, c. 1% of the radiolabel was found in cysteine and glutathione in the cotyledon. After 2 h, c. 20% of the S-35 was transported into the root-shoot axis independently of whether S-35-sulphate or S-35-cysteine was injected into the cotyledon. After 4 h, 40% of S-35 was found outside the cotyledon. Cotyledons of pea seedlings are capable of sulphate assimilation and cysteine degradation. Both sulphate and reduced sulphur were allocated from the cotyledons to the developing tissues of the pea seedlings.
  • Publication
    Emissions of the city of Augsburg determined using the mass balance method
    ( 2002)
    Kalthoff, N.
    ;
    Corsmeier, U.
    ;
    Schmidt, K.
    ;
    Kottmeier, C.
    ;
    Fiedler, F.
    ;
    Habram, M.
    ;
    Slemr, F.
    Air quality models require emission data of air pollutants with high temporal and spatial resolution. The highly resolved emissions are calculated by complex emission models and may thus be subject to considerable uncertainties. To assess the uncertainty of the emission model calculations, emissions of the city of Augsburg in southern Germany were determined experimentally on several days in October 1998 using the technique of mass balance. Two algorithms were used to estimate the CO and NOx emissions from the data measured by two research aircraft, two tethered balloons, and an airship on the lateral surface enclosing the area of investigation. The two algorithms provided results which agree within the calculated uncertainties. The differences can be attributed mainly to the different interpolation methods applied to the layer between the lowest flight level and the ground. The measurements show that on the different weekdays both CO and NOx emissions varied by about a factor of two which is much larger than the variability predicted by the emission model. Higher than predicted CO emissions were observed on Saturday, 10 October 1998, whereas NOx emissions on 10 October were substantially smaller than predicted by the emission model.
  • Publication
    Exchange of trace gases between soils and the atmosphere in Scots pine forest ecosystems of the northeastern German lowlands
    ( 2002)
    Butterbach-Bahl, K.
    ;
    Breuer, L.
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    Gasche, R.
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    Willibald, G.
    ;
    Papen, H.
  • Publication
    Tuning characteristics of InAsSb continuous-wave lasers
    ( 2002)
    Sherstnev, V.
    ;
    Krier, A.
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    Popov, A.
    ;
    Werle, P.
    We present a detailed analysis of the tuning characteristics of InAsSb continuous-wave (cw) single-frequency lasers emitting at 3.3 µm (3050 cm-1). The lasers demonstrate a tuning range of -7.5 cm-1 by changing the current and -3.5 cm-1 by changing the heat sink temperature without mode hopping. The tuning rates are of -0.015 to -0.089 cm-1/mA and -0.11 to 0.27 cm-1/K. The laser tunes to the blue side both with increasing injection current and heat sink temperature. The extended tuning is attributed to the carrier heating effect in the cw operation and the band-filling effect in the presence of strong losses.