Blar i NTNU Open på forfatter "Franzen, Christoph"
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Aeronomy of hydroxyl airglow variability by means of high-resolution telescope observations and gravity wave simulations
Franzen, Christoph (Doctoral theses at NTNU;2019:202, Doctoral thesis, 2019)Are there waves on the fjord right now? “Easy to find out”, you might think. Just go down to the water and have a look. Now imagine that you are in Oppdal, about 90 kilometres away, trying to see the waves on the fjord in ... -
Airglow Derived Measurements of Q-Branch Transition Probabilities for Several Hydroxyl Meinel Bands
Franzen, Christoph; Espy, Patrick Joseph; hofmann, niklas; Hibbins, Robert; Djupvik, Anlaug Amanda (Journal article; Peer reviewed, 2019)Spectroscopic measurements of the hydroxyl (OH) airglow emissions are often used to infer neutral temperatures near the mesopause. Correct Einstein coefficients for the various transitions in the OH airglow are needed to ... -
Modelled effects of temperature gradients and waves on the hydroxyl rotational distribution in ground-based airglow measurements
Franzen, Christoph; Espy, Patrick Joseph; Hibbins, Robert (Journal article; Peer reviewed, 2020)Spectroscopy of the hydroxyl (OH) airglow has been a commonly used way to remotely sense temperatures in the mesopause region for many decades. This technique relies on the OH rotational state populations to be thermalized ... -
Observation of Quasiperiodic Structures in the Hydroxyl Airglow on Scales Below 100 m
Franzen, Christoph; Espy, Patrick Joseph; Hibbins, Robert; Djupvik, Anlaug Amanda (Journal article; Peer reviewed, 2018)Gravity waves are known to transport energy and momentum to the middle atmosphere. The breaking processes associated with divergence of fluxes of energy and momentum into the atmosphere occur on scales that cannot be ... -
Optimizing hydroxyl airglow retrievals from long-slit astronomical spectroscopic observations
Franzen, Christoph; Hibbins, Robert; Espy, Patrick Joseph; Djupvik, Anlaug Amanda (Journal article; Peer reviewed, 2017)Astronomical spectroscopic observations from ground-based telescopes contain background emission lines from the terrestrial atmosphere's airglow. In the near infrared, this background is composed mainly of emission from ... -
Using Background OH Airglow from astronomical Observations for atmospheric Research: A Proof of Concept
Franzen, Christoph (Master thesis, 2015)The physics of the hydroxyl (OH) layer located in the Mesosphere and Lower Thermosphere (MLT) has become a focus of interest, as more and more climate models extend into this region. This is shown by the IPCC's last two ...