Browsing by Author "Taylor, M.J."
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- ItemPropagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign(München : European Geopyhsical Union, 2006) Nielsen, K.; Taylor, M.J.; Pautet, P.-D.; Fritts, D.C.; Mitchell, N.; Beldon, C.; Williams, B.P.; Singer, W.; Schmidlin, F.J.; Goldberg, R.A.As part of the MaCWAVE (Mountain and Convective Waves Ascending Vertically) winter campaign an all-sky monochromatic CCD imager has been used to investigate the properties of short-period mesospheric gravity waves at high northern latitudes. Sequential measurements of several nightglow emissions were made from Esrange, Sweden, during a limited period from 27–31 January 2003. Coincident wind measurements over the altitude range (~80–100 km) using two meteor radar systems located at Esrange and Andenes have been used to perform a novel investigation of the intrinsic properties of five distinct wave events observed during this period. Additional lidar and MSIS model temperature data have been used to investigate their nature (i.e. freely propagating or ducted). Four of these extensive wave events were found to be freely propagating with potential source regions to the north of Scandinavia. No evidence was found for strong orographic forcing by short-period waves in the airglow emission layers. The fifth event was most unusual exhibiting an extensive, but much smaller and variable wavelength pattern that appeared to be embedded in the background wind field. Coincident wind measurements indicated the presence of a strong shear suggesting this event was probably due to a large-scale Kelvin-Helmholtz instability.
- ItemSimultaneous 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).
- ItemThermal 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.