Blar i forfatter "Kero, Johan"

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    • 2018 Beam-park observations of space debris with the EISCAT radars 

      Vierinen, Juha; Kastinen, D; Markkanen, Jussi; Grydeland, Tom; Kero, Johan; Horstmann, A.; Hesselbach, S.; Kebschull, C.; Røynestad, Elisabeth; Krag, Holger (Journal article; Tidsskriftartikkel, 2019)
      Monitoring the evolution of the space debris environment requires regular radar observations of the space debris population. This study presents the results from 24 hours of beam-park observations of space objects conducted simultaneously with the EISCAT Svalbard and Tromsø radars on and between January 4th and 5th, 2018. The measurements are processed with a new matched filter bank analysis program, ...

    • 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 ...

    • Detection of meteoroid hypervelocity impacts on the Cluster spacecraft: First results 

      Vaverka, Jakub; Pellinen-Wannberg, Asta; Kero, Johan; Mann, Ingrid; De Spiegeleer, Alexandre; Hamrin, Maria; Norberg, Carol; Pitkaenen, Timo (Journal article; Peer reviewed, 2017-06-29)
      We present the first study of dust impact events on one of the Earth‐orbiting Cluster satellites. The events were identified in the measurements of the wide band data (WBD) instrument on board the satellite operating in monopole configuration. Since 2009 the instrument is operating in this configuration due to the loss of three electric probes and is therefore measuring the potential between the ...

    • EISCAT 3D: the next generation international atmosphere and geospace research radar 

      Kero, Johan; Kastinen, D; Vierinen, Juha; Grydeland, Tom; Heinselman, Craig J.; Markkanen, Jussi; Tjulin, A. (Journal article; Tidsskriftartikkel, 2019)
      EISCAT_3D is the next generation international atmosphere- and geospace research radar under development in Arctic Europe. Construction have started in September 2017 and the radar system is expected to be operational in the end of 2021. The EISCAT_3D facility will be distributed across three sites in Northern Scandinavia - in Skibotn, Norway, near Kiruna in Sweden, and near Karesuvanto in Finland. ...

    • Estimating the Space Debris Density Function using Radar Beam Park Measurements 

      Vierinen, Juha; Hermann, Frank; Kastinen, Daniel; Kero, Johan; Markkanen, Jussi; Grydeland, Tom (Journal article; Tidsskriftartikkel; Peer reviewed, 2023)
      Estimating the density of space debris as a function of orbital elements and size is crucial for determining the risk of collision of spacecraft. For objects 1 cm or larger in diameter, this information can be obtained using beam park observations made with powerful ground based radars. This study presents a novel technique for estimating the density of space debris as a function of orbital elements ...

    • 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 ...

    • Next-generation Space Object Radar Tracking Simulator: SORTS++ 

      Kastinen, D; Vierinen, Juha; Kero, Johan; Hesselbach, S; Grydeland, Tom; Krag, Holger (Journal article; Tidsskriftartikkel, 2019)
      We describe the software toolbox SORTS++ which is the next-generation Space Object Radar Tracking Simulator (SORTS). This toolbox is able to simulate general Space Surveillance and Tracking (SST) applications from catalogue maintenance to cold-start performance for radar systems or collections of radar systems. We have applied this toolbox to the EISCAT 3D radar system, currently under construction, ...

    • The science case for the EISCAT_3D radar 

      McCrea, Ian W.; Aikio, Anita; Alfonsi, Lucilla; Belova, Evgenia; Buchert, Stephan C.; Clilverd, Mark; Engler, Norbert; Gustavsson, Björn Johan; Heinselman, C.; Kero, Johan; Kosch, Mike; Lamy, Herve; Leyser, Thomas; Ogawa, Yasunobu; Oksavik, Kjellmar; Pellinen-Wannberg, Asta; Pitout, Frederic; Rapp, Markus; Stanislawska, Iwona; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-29)
      The EISCAT (European Incoherent SCATer) Scientific Association has provided versatile incoherent scatter (IS) radar facilities on the mainland of northern Scandinavia (the EISCAT UHF and VHF radar systems) and on Svalbard (the electronically scanning radar ESR (EISCAT Svalbard Radar) for studies of the high-latitude ionised upper atmosphere (the ionosphere). The mainland radars were constructed ...

    • Using radar beam-parks to characterize the Kosmos-1408 fragmentation event 

      Kastinen, Daniel; Vierinen, Juha; Grydeland, Tom; Kero, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-22)
      We describe the use of radar beam-park experiments to characterize the space debris resulting from a recent fragmentation event, the deliberate demolition of the defunct Kosmos-1408 satellite. We identify the Kosmos-1408 fragments and present distribution of measurement parameters as well as proxy orbit parameters. We present and apply a novel technique to estimate the size of objects by matching ...