Blar i forfatter "Volz, Ryan"

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    • Four-dimensional mesospheric and lower thermospheric wind fields using Gaussian process regression on multistatic specular meteor radar observations 

      Volz, Ryan; Chau, Jorge L.; Erickson, Philip J.; Vierinen, Juha P.; Urco, J. Miguel; Clahsen, Matthias (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-17)
      Mesoscale dynamics in the mesosphere and lower thermosphere (MLT) region have been difficult to study from either ground- or satellite-based observations. For understanding of atmospheric coupling processes, important spatial scales at these altitudes range between tens and hundreds of kilometers in the horizontal plane. To date, this scale size is challenging observationally, so structures are ...

    • Novel specular meteor radar systems using coherent MIMO techniques to study the mesosphere and lower thermosphere 

      Chau, J. L.; Urco, Miguel; Vierinen, Juha; Volz, Ryan; Clahsen, Matthias; Pfeffer, Nico; Trautner, Jörg (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-05)
      Typical specular meteor radars (SMRs) use one transmitting antenna and at least a five-antenna interferometric configuration on reception to study the mesosphere and lower thermosphere (MLT) region. The interferometric configuration allows the measurement of the angle-of-arrival (AOA) of the detected meteor echoes, which in turn is needed to derive atmospheric parameters (e.g., mean winds, momentum ...

    • Observing Mesospheric Turbulence With Specular Meteor Radars: A Novel Method for Estimating Second-Order Statistics of Wind Velocity 

      Vierinen, Juha; Chau, Jorge L.; Charuvil, Harikrishnan; Urco, Miguel; Clahsen, Matthias; Avsarkisov, Victor; Marino, Raffaele; Volz, Ryan (Journal article; Peer reviewed, 2019-07)
      There are few observational techniques for measuring the distribution of kinetic energy within the mesosphere with a wide range of spatial and temporal scales. <br>This study describes a method for estimating the three‐dimensional mesospheric wind field correlation function from specular meteor trail echoes. Each radar echo provides a measurement of a one‐dimensional projection of the wind velocity ...

    • Sparse signal recovery in MIMO specular meteor radars with waveform diversity 

      Urco, Miguel; Chau, Jorge Luis; Weber, Tobias; Vierinen, Juha; Volz, Ryan (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-15)
      Since the 1950s, specular meteor radars (SMRs) have been used to study the mesosphere and lower thermosphere (MLT) dynamics. Atmospheric parameters derived from SMRs are highly dependent on the number of detected meteors and the accuracy of the meteors' locations. Recently, incoherent and coherent multiple-input-multiple-output (MIMO) radar approaches combined with waveform diversity have been ...