Blar i forfatter "Lester, Mark"

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    • Atmospheric tomography using the Nordic Meteor Radar Cluster and Chilean Observation Network de Meteor Radars: Network details and 3D-Var retrieval 

      Stober, Gunter; Kozlovsky, A.; Liu, Alan; Qiao, Zishun; Tsutsumi, Masaki; Hall, Chris; Nozawa, Satonori; Lester, Mark; Belova, Evgenia; Kero, Johan; Espy, Patrick Joseph; Hibbins, Robert E.; Mitchell, N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-08)
      Ground-based remote sensing of atmospheric parameters is often limited to single station observations by vertical profiles at a certain geographic location. This is a limiting factor for investigating gravity wave dynamics as the spatial information is often missing, e.g., horizontal wavelength, propagation direction or intrinsic frequency. In this study, we present a new retrieval algorithm for ...

    • Horizontal electric fields from flow of auroral O+(2P) ions at sub-second temporal resolution 

      Tuttle, Sam; Lanchester, Betty; Gustavsson, Björn Johan; Keith Whiter, Daniel; Ivchenko, Nickolay; Fear, R. C.; Lester, Mark (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-14)
      Electric fields are a ubiquitous feature of the ionosphere and are intimately linked with aurora through particle precipitation and field-aligned currents. They exhibit order-of-magnitude changes on temporal and spatial scales of seconds and kilometres respectively which are not easy to measure; knowing their true magnitude and temporal variability is important for a theoretical understanding of ...

    • Identifying gravity waves launched by the Hunga Tonga-Hunga Ha′apai volcanic eruption in mesosphere/lower-Thermosphere winds derived from CONDOR and the Nordic Meteor Radar Cluster 

      Stober, Gunter; Liu, Alan; Kozlovsky, Alexander; Qiao, Zishun; Krochin, Witali; Shi, Guochun; Kero, Johan; Tsutsumi, Masaki; Gulbrandsen, Njål; Nozawa, Satonori; Lester, Mark; Baumgarten, Kathrin; Belova, Evgenia; Mitchell, Nicholas (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-18)
      The Hunga Tonga–Hunga Ha'apai volcano eruption was a unique event that caused many atmospheric phenomena around the globe. In this study, we investigate the atmospheric gravity waves in the mesosphere/lowerthermosphere (MLT) launched by the volcanic explosion in the Pacific, leveraging multistatic meteor radar observations from the Chilean Observation Network De Meteor Radars (CONDOR) and the ...

    • Inferring neutral winds in the ionospheric transition region from atmospheric-gravity-wave traveling-ionospheric-disturbance (AGW-TID) observations with the EISCAT VHF radar and the Nordic Meteor Radar Cluster 

      Günzkofer, Florian; Pokhotelov, Dimitry; Stober, Gunter; Mann, Ingrid Brigitte; Vadas, Sharon L.; Becker, Erich; Tjulin, Anders; Kozlovsky, Alexander; Tsutsumi, Masaki; Gulbrandsen, Njål; Nozawa, Satonori; Lester, Mark; Belova, Evgenia; Kero, Johan; Mitchell, Nicholas J.; Borries, Claudia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-18)
      Atmospheric gravity waves and traveling ionospheric disturbances can be observed in the neutral atmosphere and the ionosphere at a wide range of spatial and temporal scales. Especially at medium scales, these oscillations are often not resolved in general circulation models and are parameterized. We show that ionospheric disturbances forced by upward-propagating atmospheric gravity waves can be ...

    • Meteor radar vertical wind observation biases and mathematical debiasing strategies including the 3DVAR+DIV algorithm 

      Stober, Gunter; Liu, Alan; Kozlovsky, Alexander; Qiao, Zishun; Kuchar, Ales; Jacobi, Christoph; Meek, Chris; Janches, Diego; Liu, Guiping; Tsutsumi, Masaki; Gulbrandsen, Njål; Nozawa, Satonori; Lester, Mark; Belova, Evgenia; Kero, Johan; Mitchell, Nicholas (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-13)
      Meteor radars have become widely used instruments to study atmospheric dynamics, particularly in the 70 to 110 km altitude region. These systems have been proven to provide reliable and continuous measurements of horizontal winds in the mesosphere and lower thermosphere. Recently, there have been many attempts to utilize specular and/or transverse scatter meteor measurements to estimate vertical ...

    • Multi-instrument observations of the Pajala fireball: origin, characteristics, and atmospheric implications 

      Vierinen, Juha; Aslaksen, Torstein; Chau, Jorge L.; Gritsevich, Maria; Gustavsson, Bjorn Johan; Kastinen, Daniel; Kero, Johan; Kozlovsky, Alexandre; Kværna, Tormod; Näsholm, Sven Peter; Ulich, Thomas; Vegum, Ketil; Midtskogen, Steinar; Lester, Mark (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-07)
      Meteor observations provide information about Solar System constituents and their influx onto Earth, their interaction processes in the atmosphere, as well as the neutral dynamics of the upper atmosphere. This study presents optical, radar, and infrasound measurements of a daytime fireball that occurred on 4 December 2020 at 13:30 UTC over Northeast Sweden. The fireball was recorded with two video ...