Ground temperature history in central Europe from borehole temperature data

Abstract

SUMMARY Ground temperature histories (GTH) are inferred from temperature measurements in several boreholes of south-eastern Germany and western Bohemia (Czech Republic). The GTHs that can be extracted from these boreholes, ranging in depth between 150 and 700m, cover the past 250yr. Both data sets were inverted separately and yield consistent GTHs. They were also inverted jointly to yield a regional GTH of the past 250yr for this part of Europe. The results indicate two main episodes in the mean ground temperature with (1) a cooling period from 1750-1800 to 1930-1950, followed by (2) short colder and warmer periods until now. The same trends are found in the meteorological records at four nearby weather stations (Bayreuth, Jena, Munchen and Praha), but the meteorological record in Berlin is clearly distinct. The GTH for this part of Europe is also markedly different from one obtained in central France. These differences are consistent with the spatial variability of climatic trends.