Volume of Abstracts - Università degli Studi di Milano

5 th Int. Workshop on Ice Caves (IWIC – V)
Barzio (LC), Valsassina, Grigna and Milano, September 16 – 23, 2012
Volume of Abstracts
AIR TEMPERATURE VARIABILITY AND ICE CAVE MICROCLIMATE
CHARACTERISTICS OBSERVED IN ŽUPANOVA JAMA, SLOVENIA
Košutnik J. 1 & Ravbar N. 2
1 Cesta Ceneta Stuparja 148, 1231 Ljubljana
2 Karst Research Institute ZRC SAZU, Titov trg 2, 6230 Postojna
Detailed monitoring of cave air temperature is being carried out in a show
cave of Ţupanova jama (Mayor‟s cave) in order to reconstruct its temporal
and spatial variability patterns. The cave is located at the northern rim of
the Dinaric karst in central Slovenia. It has two entrances at the elevations
of 442 m and 477 m a.s.l. respectively. The known parts of the cave
consist of eight collapse chambers sited relatively close to surface – max.
thickness of the ceiling is 45 m. Since February 2009 monitoring was being
set up on six different locations within the cave and outside the cave.
Continuous measurements with a resolution of 30 and 60 min respectively
have been made using BaroDiver (Eijkelkamp) and T-buttons 22L. The
study focuses on two cave chambers that are opened to surface and most
influenced by the external temperature; Ledenica (Ice cave) and
Permetova dvorana (Mayor's hall). Ledenica is a lower lying chamber and
has a pocket-shaped morphology with steep descending walls. On one side
the chamber opens to the surface and on the other is connected to the
Permetova dvorana. This is a bell shaped chamber with the entrance on the
top. In Ledenica the results of air temperature time series analyses show
seasonal and daily patterns that are characteristic for ice caves. Air
temperature gradient and seasonal effect on heat exchange has been
observed. When the outside air is cooler and thus denser than the cave air,
it intrudes the cave through the lower entrance and sinks under the
warmer air by displacing it. The warmer cave air rises and flows towards
and then through the upper entrance. This upward flow is referred to as
“winter flow” which results in cooling of the cave air and rock. When cave
air is cooler than the air outside the cave, it flows from the upper entrance
down through the cave and out the lower entrance. This downward flow is
referred to as “summer flow”, leaving the lake of cold air at the bottom of
the pocket-shaped chamber isolated and stagnant. The study shows that
not only caves at higher elevations and with the presence of perennial ice,
but also special conditions, such as cave morphology can contribute to ice
cave climatic conditions.
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