Abstract:
The cave systems have a unique cave climate for each of them. This is due to the structural complexity and individuality of separate karst geosystem. At this stage there is no generalized model of the speleoclimate, but there are some regularities in the distribution, dynamics and seasonality of the speleoclimatic parameters: small annual temperature amplitude, high humidity, seasonal change in the direction of air circulation, specific gas composition. The dynamics and circulation modes of the speleoatmosphere are determined by the morphology of the cave system and climatic conditions (the difference in air density caused by differences in temperature and pressure on the surface and in the cave, system determine the changes of the ventilation regimes of the cave atmosphere). The seasonal change in the direction and intensity of the ventilation regimes in the karst caves is a leading factor determining the gas composition of the speleoatmosphere during the different seasons. The average annual temperatures in the explored caves fluctuate in a wide rage – from 6,6 °C for Ivanova Voda cave, to 11,5 °C for Stara cave. In the caves where rivers flow, it has been established specific temperature regimes to each of them and the relative humidity of the cave air. Based on the measured temperatures in the investigated caves, the microclimatic zones in them has been determined. There are three zones in the caves under study, and in some of them are located and subzones formed by the influence of the morphology of the cave. The results of the microclimatic monitoring in the investigated caves are used to clarify the influence of their ventilation regimes on the volumetric activity of the radon. The purpose of this study is to investigate the microclimate of selected model caves with different morphology and temperature regimes in the Western Rhodopes.