RECONSTRUCTION OF HIGH-RESOLUTION GROUND TEMPERATURE HISTORIES COMBINING DENDROCHRONOLOGICAL AND GEOTHERMAL DATA

in an attempt to obtain robust records of past climatic variations, ge othermal temperature-depth data have been combined with dendrochronolo gical data to yield high resolution ground temperature histories. Sinc e the resolution of the dendrochronological record and the ground temp erature history inferred from geothermal data are different, compariso n of these records is made possible by multiplying the dendrochronolog ical data by the model resolution matrix for the geothermal data inver sion. tinder this condition, we find that a simple transformation betw een tree-ring indices and ground temperature changes allows us to inte rpret tree-ring widths in terms of ground temperatures, thus yielding a high resolution ground temperature history which explains the observ ed subsurface temperature regime. The linear transformation relating t he ground temperature changes and average variations from the tree-rin g chronology was found to be Delta T-g = 9.93I(average).