Solar activity effects on cave temperature regimes during five solar cycles (1968 - 2018)

The problems associated with the influence of solar activity on the state of the Earth’s low atmosphere and climate are some of the most important in modern solar-terrestrial physics. On the other hand, it has an impact on the microclimate of the caves in the zone of constant temperature through various physical mechanisms.

Variations in solar activity are accompanied by changes in the flux of solar radiation, disturbances in the solar wind and interplanetary magnetic field, the dynamics of the fluxes of solar and galactic cosmic rays and are especially clear expressed in the scale of the 11 year solar cycle. This applies in particular to the energy transfer and exchange in the Earth’s atmosphere and the influence on various atmospheric processes. Usually, several factors simultaneously affect the atmosphere and this makes it difficult to study the physical mechanisms that shape the atmospheric response. This overlay of energy impacts also affects the thermodynamic processes of heat and moisture transfer in Karst massifs and caves. In addition, due to the presence of thermal flux from the lithosphere and the thermal inertness of the volume and mass of the Karst itself, some filtration of the direct physical factors of impact is obtained.

The response of the earth’s atmosphere (atmospheric pressure, temperature, cloudiness, etc.) and the impact on the cave atmosphere of solar activity may differ significantly depending on the specific Karst region and geographical location. The correlation between atmospheric characteristics and solar geophysical factors prove to be unstable over time – they may intensify, change the sign, or cease altogether.

This report presents a study of the correlation between thermodynamic characteristics of the cave atmosphere (temperature, humidity) and heliophysical indices for the period 1968 – 2018 for four caves on the territory of Bulgaria. Correlation between atmospheric rainfall in the region and thermodynamic changes in the atmosphere of the caves is investigated. A relationship between the cave microclimate and the temperature and barometric pressure of the ground atmosphere is also found. This is probably due to the influence of the pressure of major atmospheric fronts on the Balkan Peninsula.

Authors: Penka Stoeva, Alexey Stoev – Space Research and Technology Institute, BAS, Stara Zagora Department

Section: Symposium “Cave Climate and Paleoclimate – Best Record of the Global Change IV”

Type: poster presentation

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