EGU2020-9194
https://doi.org/10.5194/egusphere-egu2020-9194
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Study of seasonal and short-term temperature variations in the middle atmosphere using cosmic muons

Matias Tramontini1, Marina Rosas-Carbajal2, Christophe Nussbaum3, Dominique Gibert4, and Jacques Marteau5
Matias Tramontini et al.
  • 1Universidad Nacional de La Plata, Facultad de Ciencias Astronómicas y Geofísicas, Geofísica Aplicada, Argentina (mtramontini@fcaglp.unlp.edu.ar)
  • 2Institut de Physique du Globe de Paris
  • 3Swiss Geological Survey at Swisstopo
  • 4Géosciences Rennes
  • 5Institut de Physique des 2 Infinis de Lyon

In the last decades, large particle-physics experiments have shown that muon rate variations detected in underground laboratories are sensitive to regional, middle-atmosphere temperature variations. Therefore, muon measurements may be used to study middle-atmosphere dynamics, including short-term phenomena such as Sudden Stratospheric Warmings. In this work we use a portable muon detector conceived for geosciences applications. We study seasonal and short-term variations in the middle-atmosphere’s temperature by analyzing a year of continuous muon measurements at the Mont Terri underground rock laboratory. This site is located in the Jura Mountains in north-western Switzerland, at a depth of ~300 meters below the Earth's surface. We observe a direct correlation between middle‐atmosphere seasonal temperature variations and muon rate. Muon rate variations are also sensitive to the abnormal atmosphere heating in January-February 2017, associated to a major Sudden Stratospheric Warming that in a few days increased the zonal mean temperature in the polar region by more than 20 K. We estimate the effective temperature coefficient for our particular case and found that it agrees with theoretical models and with those calculated from large neutrino experiments under comparable conditions. Finally, we discuss the implications of our observations for the Atmospheric Sciences community.

How to cite: Tramontini, M., Rosas-Carbajal, M., Nussbaum, C., Gibert, D., and Marteau, J.: Study of seasonal and short-term temperature variations in the middle atmosphere using cosmic muons, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9194, https://doi.org/10.5194/egusphere-egu2020-9194, 2020

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Display material version 1 – uploaded on 27 Apr 2020
  • CC1: Comment on EGU2020-9194, Martin Schrön, 07 May 2020

    Hi Matias, thanks for the very nice presentation. I am wondering what are the uncertainties introduced by this temperature effect and how they compare to the variation of incoming cosmic rays. Do you think that muon detection could be used to determine the temperature of the atmosphere despite of the cosmic fluctuations? Or the other way round, if you would use the muon detector to measure incoming cosmic rays, what would be the error by not knowing the atmospheric temperature?

    Thanks,
    Martin

    • AC1: Reply to CC1, Matias Tramontini, 08 May 2020

      Hi Martin, thanks a lot for you comment. That is actually an interesting point.

      Particularly, when deploying a muon detector underground, the measured muon rate relative variations has been found to be proportional to the atmospheric effective temperature relative variations.

      So, by theoretically estimating the proportionality coefficient, I think that muon detection could be used to estimate the atmospheric effective temperature relative variations, but not the absolute value of the atmospheric effective temperature itself.

      For our experiment, we have found the proportionality coefficient to be of 0.68+/-0.04 (Figure IV), so the error for not accounting for the atmosphere’s effect would be quite significant if one would interpret that the fluctuations observed in the muon rate correspond to variations of groundwater content, for example.

      I will look further into the variation of incoming cosmic rays you mention. I thank you in advance if you have any suggestions for documentation on this subject.

      Best,

      Matias