J. Safanda et D. Rajver, Signature of the last ice age in the present subsurface temperatures in the Czech Republic and Slovenia, GLOBAL PLAN, 29(3-4), 2001, pp. 241-257
Ground surface temperature (GST) history can be evaluated by analysing the
present-day temperature-depth profiles measured in boreholes. Due to the di
ffusive character of the process, however, the resolution of the method dec
reases quickly for the more remote events. The reconstructed GST at a given
moment in the past is a weighted average of temperature over a certain per
iod of time. The present study shows that because the cold climate of the l
ast (Weichselian) glacial prevailed in the period of 75-10 ka, there is a c
hance to obtain its mean GST, despite the large averaging intervals, from t
emperature profiles measured in deep boreholes. This fact is demonstrated o
n the GST inversions of carefully selected profiles, three from the Czech R
epublic and two from Slovenia, the depth of which ranges between 1.5 and 2.
4 km. They yield GST histories with a minimum between 19 and 10 ka followed
by a warming of 6-15 K. In order to suppress the nonclimatic noise and to
extract the common signal, the joint inversions were carried out for the Cz
ech and the Slovenian boreholes, respectively. The Czech data show the mini
mum at 17 ka and the warming of 8 K. The Slovenian data have the minimum at
16 ka and the warming amounts to 7 K. These results agree well with inform
ation extracted earlier from the German KTB super deep borehole, where the
inversion of the temperature log indicated 10 K warming since the glacial m
inimum, and represent an independent estimate of the difference between gla
cial and interglacial conditions typical for the region of Central Europe.
(C) 2001 Elsevier Science B.V. All rights reserved.