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search.filters.applied.f.access: openAccess × Author: Höffner, J. × Start date: 2018 × WGL Institute: IAP ×

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    Thermal structure of the mesopause region during the WADIS-2 rocket campaign
    (Göttingen : Copernicus GmbH, 2019) Wörl, R.; Strelnikov, B.; Viehl, T.P.; Höffner, J.; Pautet, P.-D.; Taylor, M.J.; Zhao, Y.; Löbken, F.-J.
    This paper presents simultaneous temperature measurements by three independent instruments during the WADIS-2 rocket campaign in northern Norway (69° N, 14° E) on 5 March 2015. Vertical profiles were measured in situ with the CONE instrument. Continuous mobile IAP Fe lidar (Fe lidar) measurements during a period of 24 h, as well as horizontally resolved temperature maps by the Utah State University (USU) Advanced Mesospheric Temperature Mapper (AMTM) in the mesopause region, are analysed. Vertical and horizontal temperature profiles by all three instruments are in good agreement. A harmonic analysis of the Fe lidar measurements shows the presence of waves with periods of 24, 12, 8, and 6 h. Strong waves with amplitudes of up to 10K at 8 and 6 h are found. The 24 and 12 h components play only a minor role during these observations. In contrast only a few short periodic gravity waves are found. Horizontally resolved temperatures measured with the AMTM in the hydroxyl (OH) layer are used to connect the vertical temperature profiles. In the field of view of 200km×160km only small deviations from the horizontal mean of the order of 5K are found. Therefore only weak gravity wave signatures occurred. This suggests horizontal structures of more than 200 km. A comparison of Fe lidar, rocket-borne measurements, and AMTM temperatures indicates an OH centroid altitude of about 85 km. © 2019 Copernicus GmbH. All rights reserved.
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    Simultaneous in situ measurements of small-scale structures in neutral, plasma, and atomic oxygen densities during the WADIS sounding rocket project
    (Göttingen : Copernicus GmbH, 2019) Strelnikov, B.; Eberhart, M.; Friedrich, M.; Hedin, J.; Khaplanov, M.; Baumgarten, G.; Williams, B.P.; Staszak, T.; Asmus, H.; Strelnikova, I.; Latteck, R.; Grygalashvyly, M.; Lübken, F.-J.; Höffner, J.; Wörl, R.; Gumbel, J.; Löhle, S.; Fasoulas, S.; Rapp, M.; Barjatya, A.; Taylor, M.J.; Pautet, P.-D.
    In this paper we present an overview of measurements conducted during the WADIS-2 rocket campaign. We investigate the effect of small-scale processes like gravity waves and turbulence on the distribution of atomic oxygen and other species in the mesosphere-lower thermosphere (MLT) region. Our analysis suggests that density fluctuations of atomic oxygen are coupled to fluctuations of other constituents, i.e., plasma and neutrals. Our measurements show that all measured quantities, including winds, densities, and temperatures, reveal signatures of both waves and turbulence. We show observations of gravity wave saturation and breakdown together with simultaneous measurements of generated turbulence. Atomic oxygen inside turbulence layers shows two different spectral behaviors, which might imply a change in its diffusion properties. © 2019 Author(s).
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    Simultaneous observations of NLCs and MSEs at midlatitudes: Implications for formation and advection of ice particles
    (Göttingen : Copernicus GmbH, 2018) Gerding, M.; Zöllner, J.; Zecha, M.; Baumgarten, K.; Höffner, J.; Stober, G.; Lübken, F.-J.
    We combined ground-based lidar observations of noctilucent clouds (NLCs) with collocated, simultaneous radar observations of mesospheric summer echoes (MSEs) in order to compare ice cloud altitudes at a midlatitude site (Kühlungsborn, Germany, 54° N, 12° E). Lidar observations are limited to larger particles ( > 10 nm), while radars are also sensitive to small particles ( < 10 nm), but require sufficient ionization and turbulence at the ice cloud altitudes. The combined lidar and radar data set thus includes some information on the size distribution within the cloud and through this on the of the cloud. The soundings for this study are carried out by the IAP Rayleigh-Mie-Raman (RMR) lidar and the OSWIN VHF radar. On average, there is no difference between the lower edges (lowNLC and lowMSE). The mean difference of the upper edges upNLC and upMSE is g1/4 500 m, which is much less than expected from observations at higher latitudes. In contrast to high latitudes, the MSEs above our location typically do not reach much higher than the NLCs. In addition to earlier studies from our site, this gives additional evidence for the supposition that clouds containing large enough particles to be observed by lidar are not formed locally but are advected from higher latitudes. During the advection process, the smaller particles in the upper part of the cloud either grow and sediment, or they sublimate. Both processes result in a thinning of the layer. High-altitude MSEs, usually indicating nucleation of ice particles, are rarely observed in conjunction with lidar observations of NLCs at Kühlungsborn. © Author(s) 2018.