Atmospheric circulation influence during winter on change of air pressure, temperature and spectral transparency at Yakutsk Array

Abstract

The paper presents long-term observations of the atmosphere in Yakutsk region. Analysis of the data for 40 year period indicates a gradual strengthening of cyclonic activity in the region and hence the increase of the average winter temperature, increase variations of the rest atmosphere, which greatly softens the continental climate of Central Yakutia.

Aerosol in spring-summer-autumn-winter cycles by observation at Yakutsk EAS array in 2004-2013.

“…Igor Petrov series of these parameters have been created, which allow us to get correction coefficients and apply them in the primary analysis of EAS. At the same time it is possible to analyze the series of geophysical data and get more information about changing parameters of the atmosphere and climate as a whole [12]. For example, analysis of the AOT and transparency of the atmosphere for a long period of time, revealed a seasonal variation of these parameters in the context of the spring -summer -autumn -winter cycle, which is important for air showers data averaging for the annual and long-term perspective observations as well.…”

On irregularities in the cosmic ray spectrum of $10^{16}-10^{18}$ eV range

“…in winter a non-standard atmosphere is formed above the array, the parameters that differ significantly from the atmosphere during summer period. As it was shown in the papers [12,14] in winter, with near-ground mists and haze, the maximum flux attenuation of Cherenkov light at distances of 100-400 m from the shower axis reaches ∼ (30-40)%, while under excellent weather conditions the losses do not exceed 10%, which occurs due to Rayleigh scattering of the light in the atmosphere. Because of this, constant observations of the atmosphere are conducted at the Yakutsk array during optical observation periods [14] and the obtained data on the atmospheric transparency are taken into account when determining certain characteristics of air showers, in particular, energy and depth of maximum development of the EAS [15].…”

Muons in showers with energy $\boldsymbol{E_{0} \geq}$ 5 EeV and QGSjetII-04 and EPOS LHC models of hadronic interactions. Is there a muon deficit in the models?

“…The Yakutsk array has been a testing ground for the study of cosmic radiation in the field of ultra-high and highest energies for 50 years. The complex registration of charged particles, muons, Cherenkov light and air shower radio emission, together with the developed software for the preliminary and subsequent analysis of showers, made it possible to study the radial and longitudinal development of showers and determine their main characteristics [12,18,32,36,37]. Large statistics of showers with a good precision made it possible to create a database in the energy range 10 15 − 10 20 eV for the study of air shower physics.…”