EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Semidiurnal tidal signatures in microbarom infrasound array measurements

Sven Peter Näsholm1, Ekaterina Vorobeva1,2, Alexis Le Pichon3, Yvan J. Orsolini4, Antoine L. Turquet1, Robert E. Hibbins2, Patrick J. Espy2, Marine De Carlo3,6, Jelle D. Assink5, and Ismael Vera Rodriguez1
Sven Peter Näsholm et al.
  • 1NORSAR, Kjeller, Norway (
  • 2Norwegian University of Science and Technology (NTNU), Department of Physics, Trondheim, Norway
  • 3CEA/DAM/DIF, DASE, Arpajon, France
  • 4Norwegian Institute for Air Research (NILU), Kjeller, Norway
  • 5Royal Netherlands Meteorological Institute (KNMI), R&D Seismology and Acoustics, De Bilt, Netherlands
  • 6Univ. Brest, CNRS, IRD, Ifremer, Laboratoire d’Oceanographie Physique et Spatiale (LOPS), IUEM, Brest, France

Recent studies on infrasonic signatures related to atmospheric tides are mostly focused on stratospherically ducted infrasound or on tidal signatures in recorded infrasound signal power.

In the current work, we address microbarom infrasound ducted by mesosphere-lower thermosphere (MLT) waveguides and the associated infrasound apparent velocity (trace velocity) of arrivals at a ground-based array station in northern Norway.

A hypothesis is that the infrasound apparent velocity – which is related to the incidence angle of the wavefront impinging the station – is linked to the altitude of the final refraction of the infrasound waves. This altitude would be affected by the regional MLT tidal pattern.

We apply specialized beamforming and filtering recipes to highlight the MLT-ducted microbarom arrivals and we find semidiurnal patterns in the infrasound apparent velocity measurements.

How to cite: Näsholm, S. P., Vorobeva, E., Le Pichon, A., Orsolini, Y. J., Turquet, A. L., Hibbins, R. E., Espy, P. J., De Carlo, M., Assink, J. D., and Vera Rodriguez, I.: Semidiurnal tidal signatures in microbarom infrasound array measurements, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19035,, 2020


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