Description: Das Projekt "Transfer over Ecosystems of Reduced nitrogen by Mass Spectrometry (TERMS)" wird vom Umweltbundesamt gefördert und von Forschungsanstalt Agroscope Reckenholz-Tänikon ART durchgeführt. The project 'Transfer over Ecosystems of Reduced Nitrogen by Mass Spectrometry' (TERMS) proposes to adopt Proton Transfer Reaction Mass Spectrometry (PTR-MS) to measure ambient concentrations of ammonia and selected volatile organic nitrogenous compounds. The project also aims at measuring turbulent ammonia fluxes using eddy covariance approaches by taking advantage of the fast time resolution of PTR-MS. The project consists of the following three parts: a) Instrument development: The PTR-MS instrument will be operated in a new mode, using O2+ as the reagent ion instead of H3O+. Because NH3 is a very sticky molecule, memory effects in the inlet system -- including the sampling line and the transfer into the drift tube of the instrument -- limit the time resolution and present major challenges to the application in an eddy covariance approach. A series of optimizations will be performed to lower memory effects to a degree that the losses can be corrected for. b) Concentration measurements of ammonia and other volatile organic nitrogen species: Measurements will be carried out at the NitroEurope grassland site Oensingen in Switzerland. The focus of the ammonia measurements is the characterization of the temporal dynamics of ambient concentrations at diurnal to seasonal time scales, with a special focus on the morning breakup of the nocturnal boundary layer. In addition the concentrations of selected volatile organic nitrogen compounds will be measured in order to assess their relevance for atmospheric chemistry processes. c) Ammonia exchange flux measurements at NitroEurope sites: The modified and improved PTR-MS system will be applied to measure ammonia exchange fluxes with an eddy covariance approach over several months. We focus on temperate grasslands systems that dominate agricultural production in Switzerland, covering about 69Prozent of the agricultural land. On the European scale this fraction amounts to 49Prozent, representing 30Prozent of the total land area. Grasslands are alternately important sinks and sources for reduced nitrogen, and thus influence the fraction of total emitted reduced nitrogen that is deposited downwind onto semi-natural and natural areas. The quantification of exchange fluxes is crucial for the evaluation of the ecological problems related to the N-cycle. The core of the project is a dissertation focusing on the characterization of the concentrations and fluxes of reduced nitrogen compounds over grassland systems. The PhD candidate can build on the large experience of our group both in field measurements and in the application of eddy covariance techniques for flux measurements of reactive trace gases.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Spülsaum ? Ammonium ? Ammoniak ? Ammoniumverbindung ? Messstation ? Stickstoffgehalt ? Stickstoffverbindung ? Ökologie ? Skigebiet ? Spurengas ? Stickstoff ? Organische Stickstoffverbindung ? Wiese ? Schweiz ? Grünland ? Massenspektrometrie ? U-Bahn ? Wirkung ? Gasförmiger Stoff ? Pestizidabdrift ? Bewertung ? Landfläche ? Ackerland ? Agrarproduktion ? Anwendungstechnik ? Bohrkern ? Ionen ? Standortwahl ? Technik ? Sediment ? Naturraum ? Schaden ? Wirkung ? Messung ? Naturlandschaft ? Produktion ? Atmosphärenchemie ? Forschungseinrichtung ? Grenzschicht ? Landwirtschaft ? Ökosystem ? Fahrradfahren ? Turbulenz ? Landwirtschaftliche Fläche ? Maßnahme ? Abdeckung ? Versuchsperson ? Art [Spezies] ? BEWERTEN ? AUSGEWAEHLT ? DAUER ? VERSCHIEBUNG ? VERBINDUNG ? EINGESCHRAENKT ? ENTWICKLUNG ? SONSTIG ? Erlass [Recht] ? FRAKTION ? GEGENWART ? GRUPPE ? Verwertung ? BESCHREIBUNG ? JAHRESZEITLICH ? Konzentrat ? LAND ? WICHTIG ? Werkzeug ? BESONDER ? NAECHTLICH ? VERWANDT ? ANGEWANDT ? TEIL ? NEU ? VERARBEITEN ? PROBE ? PROJEKT ? AUSTAUSCHEN ? BETRAG ?
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2008-06-01 - 2011-05-31
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