Physikalisch-chemische Prozesse in der Stratosphaere

Description: Dieser Antrag fasst die folgenden Einzelvorhaben zusammen: 1. Laboruntersuchungen zur Kinetik von Ionen- und Radikal-Konversionsreaktionen und Photolyseprozess innerhalb stratosphaerischer fluessiger Aerosol-Teilchen (Antrag-Nr. 095068), 2. Experimentelle Untersuchungen zum Wachstum und Gefrierverhalten von stratosphaerischen Aerosol- und PSC-Einzelteilchen (Antrag-Nr. 095135), 3. Studie zur Ozon-Restauration durch photochemische Prozesse (Antrag-Nr. 0 95136), 4. Koordination des Deutschen Ozonforschungsprogramms (Antrag- Nr. 0 95 xxx).

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Tags: Atmosphärisches Aerosol ? Photochemie ? Atmosphärenmodell ? Ozonschicht ? Stratosphäre ? Studie ? Modellierung ? Atmosphärenchemie ? Laboruntersuchung ? Ozon-Restauration ? optical levitation ? polar stratospheric clouds ? radical interconversion ? raman spectroscopy ? stratospheric aerosol chemistry ?

Region: Nordrhein-Westfalen

Bounding boxes: 5.8662503507406045° .. 9.461478369136085° x 50.323011952581965° .. 52.53144342795586°

License: Creative Commons Namensnennung-keine Bearbeitung-Nichtkommerziell 4.0

Language: Deutsch

Organisations

• Bundesministerium für Forschung, Technologie und Raumfahrt (Finanzielle Förderung)
• Umweltbundesamt (Bereitstellung)
• Universität-Gesamthochschule Essen, Fachbereich 8 Chemie, Institut für Physikalische und Theoretische Chemie (Projektverantwortung)

Last harvest: 15.05.2026 00:27

Time ranges: 1996-04-01 - 1999-12-31

Alternatives

• Language: Englisch/English
  Title: Physical-chemical processes in the stratosphere
  Description: This applications has four different projects: 1. Laboratory Studies of the Kinetic of lon and Radical Conversion Reactions and Photolysis Processes in Stratospheric Liquid Aerosol Particles: Chemical reactions in liquid stratospheric aerosol particles such as SSAs and STSs have been identified to be potential contributors to the chemical activation of CIOy and BrOy species. Since the main oxidative capacity in the stratospheric liquid phase is by the radicals OH and NO3 as well as by the radical anion SO4 conversion reactions of these species under stratospheric conditions will be investigated. Furthermore photochemical OH sources at stratospheric temperatures and liquid phase compositon will be studied. The project consists of three separate parts: 1. Kinetic studies of radical interconversion reactions at relevant stratospheric temperatures and solution compositions. 2. Investigations of photochemical in-situ radical sources under stratospheric conditions. 3. Implication studies of the processes investigated. 2. Laboratory Studies of the Growth and Freezing of Stratospheric Aerosol-and PSC-Particles: Heterogeneous processes on stratospheric aerosols and polar-stratospheric clouds (PSC) play an important role in the activation and passivation of reservoir gases such as CIONO2, HCI, BrONO2, HBr and N2O5. Knowledge of the growth of aerosol particles and their phase transitions upon cooling as well as their influence on the chemistry of the polar stratosphere are important for an improved understanding of these stratospheric processes. Stratospheric particles mainly consist of HNO3, H2O and H2SO4. Their actual composition and physical state as a function of ambient conditions, however, is as yet not well defined. The growth of single stratospheric sulfate aerosol particles and their freezing behaviour will be investigated in laboratory experiments. Single H2So4 minus particles will be isolated by means of optical levitation using an Ar-ion laser in a well defined volume of air with simulated stratospheric conditions with respect to pressure, temperature and compositon. Information about their chemical content is derived from the inelastically scattered light (Raman-effect) whereas their size can be measured by analyzing the elastic scattered light (interference, Mie-effect). Freezing of the particles will be observed by the appearance of additional peaks in the Raman-spectrum and the depolarization of the scattered light. The temperature of the particles will be determined from the Stokes/Anti-Stokes-rates of the Raman signals. Variation of the composition of the gas-phase (H2O/HNO3 partial pressure) leads to condensation-/evaporation-processes which are investigated by observation of the droplet-size and intensity ratios of characteristic peaks in the Raman spectrum. https://ufordat.uba.de/UFORDAT/pages/PublicRedirect.aspx?TYP=PR&DSNR=56007

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