Highly sensitive and selective measurements of NO2 on HALO
Zusammenfassung der Projektergebnisse
The instrument proposed to measure NO2 directly using laser-induced fluorescence (LIF) has been evolved from a prototype to a reliable field instrument with high sensitivity and precision. A first deployment during the PARADE campaign yielded first field data as well as an intercomparison with another 4 NO2 instruments using different techniques. All instruments agreed with each other within their respective limits of confidence. However, GANDALF, our laser-induced fluorescence instrument, showed best agreement with the MPI cavity-ringdown spectrometer (CRDS), which, like LIF, measures NO2 directly without having to rely on prior conversion to NO. CRDS is also the instrument with the best precision after GANDALF. However, since measurements in CRDS take place at ambient pressure, while the LIF measurements in GANDALF take place in a reduced pressure, GANDALF is more readily adaptable to airborne measurements. GANDALF was further adapted to fit the requirements for certification on HALO, requiring integration into the existing HORUS LIF instrument. In the resulting setup HORUS and GANDALF shared common resources like the power-expensive pumps and were mounted together on the same porthole and racks, enabling the NO2 measurements with very little additional power and weight. Extensive programming to automize the instrument allowed for largely autonomous operation during flights. GANDALF was successfully deployed during the OMO campaign in summer 2015, yielding valid data during all flights with a precision of 1% or 15 ppt.
Projektbezogene Publikationen (Auswahl)
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Investigation of the photo stationary state of NOx during the PARADE field experiment using a novel Gas Analyzer for Nitrogen Dioxide Applying Laserinduced Fluorescence. EGU General Assembly 2013, held 7-12 April, 2013 in Vienna, Austria, id. EGU2013-12431
Javed, Umar, Dagmar Kubistin, Monica Martinez, Markus Rudolf, Andreas Reiffs, Uwe Parchatka, Anke Nölscher, Wei Song, Jim Thieser, Birger Bohn, Denis Pöhler, Florian Berkes, Rolf Sander, John Crowley, Jonathan Williams, Peter Hoor, Horst Fischer, Jos Lelieveld, and Hartwig Harder
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The link between atmospheric radicals and newly formed particles at a spruce forest site in Germany. Atmos. Chem. Phys., 14, 10823–10843, 2014
Bonn, B., E. Bourtsoukidis, T. S. Sun, H. Bingemer, L. Rondo, U. Javed, J. Li, R. Axinte, X. Li, T. Brauers, H. Sonderfeld, R. Koppmann, A. Sogachev, S. Jacobi, and D. V. Spracklen
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The sensitivity of the photostationary state of NOx and its implication for the oxidation capacity in a semi-rural and boreal forest region. Dissertation, Uni Mainz, 2014
Javed, Umar
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WP4- NA4: Trace gases networking: Volatile organic carbon and nitrogen oxides. Deliverable D4.6: Results of NOx side-by-side intercomparison exercise of ambient air and test gases, ACTRIS IA in FP7 Final Report, 2015
Gilge, Stefan und Christian Plass-Dülmer
