A total of six Tinytag Plus 2 data loggers were used in a study whose final aim is to reconstruct past climate changes recorded by stalagmites from these caves.
The team of scientists from the Emil Racoviță Institute of
Speleology in Bucharest was led by Dr Virgil Drăgușin. The caves
are part of a karst system - a landscape characterised by the
presence of caves, potholes, dry valleys and sinkholes, resulting
from the corroding effects of slightly acidic groundwater on
Although placed in a harsh environment, where relative humidity
is always close to 100%, the Plus 2 TGP-4500 data loggers were able
to record variations in cave air and rock temperature as small as a
few thousands of a degree Celsius.
Analysis of the recorded data showed semi-diurnal cycles in the
temperature, with minimum levels both in the late morning and in
the evening, while maximum levels were observed during the
afternoon and in the early morning. The research investigated if
these temperature changes could be caused by earth or atmospheric
tides (an effect of the combined gravitational action of the moon
and the sun) rather than by the day and night temperature changes
of the surface. Advanced statistics helped the team understand that
the small temperature variability was induced by atmospheric
pressure tides caused by the sun.
Further, the team verified if cave air temperature could have
also been influenced by moon-produced tidal forces, via rock
temperature variations. To this end, another Tinytag Plus 2
TGP-4020 data logger with an external PB-5001 temperature probe was
completely buried inside the limestone cave wall. The free space
left around the handle was filled with cement to ensure the probe
was in direct contact with the rock over its entire surface and
isolated from interacting with the cave atmosphere.
Results confirmed that semi-diurnal variability seen in cave air
was not present in the rock temperature, therefore the team states
that the surrounding rock is controlling air temperature on
monthly, but not semi-diurnal timescales, and hence there was no
reason to consider an influence of lunar tides in the cave air
Dr Virgil Drăgușin notes "We used Tinytags for a long time and
are very happy with their reliability for this very specific area
of climate research. But during the study described here we were
even happier to find them to be more sensitive than what we knew
from the product data sheet, allowing us to record the hardly
noticeable influence of solar tides on cave temperature. It could
well open up new opportunities for using these data loggers in the
fields of geodynamics or atmosphere physics."
The Team at Tinytag was delighted to be involved with the
Project, commenting "Cave monitoring is yet another example of how
the Plus 2 range of data loggers is ideally suited for use in harsh
or remote locations for long periods if required."
A link to the full Project report can be found