Solar cycle variation of the ionization by cosmic rays in the atmosphere at the mid-latitude region of Athens

• Published in: Astrophysics and space science Vol. 366; no. 7
• Main Authors: Makrantoni, P., Mavromichalaki, H., Paschalis, P.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-07-2021; Springer Nature B.V
• Subjects: Astrobiology; Astronomy; Astrophysics; Astrophysics and Astroparticles; Atmosphere; Cosmic ray intensities; Cosmic ray particles; Cosmic ray showers; Cosmic rays; Cosmology; Earth surface; Equatorial regions; Galactic cosmic rays; Geomagnetic latitude; Ionization; Latitude; Magnetospheres; Observations and Techniques; Original Article; Physics; Physics and Astronomy; Polar environments; Polar regions; Rigidity; Sea level; Sea level monitoring; Seasonal variations; Solar cycle; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Space weather; Upper atmosphere; Neutron monitors; Solar cycle; Ionization; Atmosphere; Cosmic rays
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/s10509-021-03978-8

In this study, the ionization rate in the atmosphere induced by solar and galactic cosmic rays is calculated for the region of Athens (Greece) during the time period from 1996 to 2019 covering the last two solar cycles 23 and 24. In order to compute the cosmic ray induced ionization, the corresponding model of the University of Oulu was used along with its new version which is extended to the upper atmosphere. This model has been applied to the entire atmosphere, i.e., from the atmospheric depth of 0.00 g/cm
2
corresponding to the upper limit of the atmosphere (∼40 km), to that one of 1025 g/cm
2
corresponding to the Earth’s surface. Furthermore, an application has been made as a function of rigidity and geomagnetic latitude, from 0.1 GV (∼90
∘
polar regions) to 14.9 GV (∼0
∘
equatorial regions). Specifically, we focus at the region of Athens that is a middle latitude one, located at 38
∘
N geographic latitude, and cosmic ray intensity is recorded by the sea level (260 m) neutron monitor station of the National and Kapodistrian University of Athens. Cosmic ray particles with a vertical cut-off rigidity of 8.5 GV are measured in real time and magnetospheric effects of the cosmic ray intensity with the maximum amplitude in the north hemisphere, are often observed. A comparison of the calculated cosmic ray induced ionization in this region with the ionization of polar and equatorial regions during the different phases of the solar cycles 23 and 24, is performed. A seasonal variation of this ionization during all the examined period is for first time observed. Obtained results are discussed in terms of Space Weather applications.