Climate of the Past www.clim-past.net 1814-9324 1814-9332 3 2 2007 10.5194/cp-3-315-2007 http://www.clim-past.net/3/315/2007/ http://www.clim-past.net/3/315/2007/cp-3-315-2007.html http://www.clim-past.net/3/315/2007/cp-3-315-2007.pdf 315 324 2007-06-15 Thermal log analysis for recognition of ground surface temperature change and water movements M. Verdoya verdoya@dipteris.unige.it P. Chiozzi V. Pasquale Dipartimento per lo Studio del Territorio e delle Sue Risorse, Settore di Geofisica, Università di Genova, Viale Benedetto XV 5, 16132 Genoa, Italy A joint analysis of surface air temperature series recorded at meteorological stations and temperature-depth profiles logged in nearby boreholes was performed to estimate conditions existing prior to the beginning of the instrumental record in central-northern Italy. The adopted method considers conductive and advective heat transport in a layered medium and provides simultaneous estimates of the pre-observational temperatures and the Darcy velocities. The reconstruction of the ground surface temperature history using a generalised least-squares inversion method was performed for boreholes where hydrological disturbances to measured temperature logs were proved negligible. Both methods revealed generally coherent climatic changes in the whole investigated area. Climatic conditions were generally warm and comparable with the reference period 1960–1990. The absence of the Little Ice Age seems to be a generic feature of the climate in central-northern Italy. Climate change of the 19th century was generally insignificant with well-balanced periods of cold and warmth. The investigated area became significantly colder only at the end of the 19th century. Cooling culminated around 1950 when it was replaced by rapid warming. Recent warming was not inferred only for one of the investigated holes. Anderson, M. P.: Heat as a ground water tracer, Ground Water, 43(6), 951–968, 2005. Baldi, P., Bellani, S., Ceccarelli, A., Fiordalisi, A., Squarci, P., and Taffi, L.: Nuovi dati geotermici nelle aree a Sud-Est ed a Sud del campo geotermico di Travale (Toscana), Atti del 13° Convegno GNGTS, CNR, Roma, pp. 211–221, 1994. Beltrami, H. and Harris, R. H. (Eds.): Inference of climate change from geothermal data (Special Issue), Global Planet. Change, 29, 149–348, 2001. Bodri, L., Chiozzi, P., Pasquale, V., and Verdoya, M.: Last 1000 years climate reconstruction inferred from geothermal measurements in Italy, Proceedings of the 2nd Int. Conf. European Soc. for Environmental History, Prague 2003, pp. 16–22, 2003. Bodri, L. and \vCermák, V.: Climate changes in the last millennium inferred from borehole temperatures: results from the Czech Republic – part I, Global Planet. Change, 11, 111–125, 1995. Bodri, L. and \vCermák, V.: High frequency variability in recent climate and the north Atlantic oscillation, Theor. Appl. Climatol., 74, 33–40, 2003. Bodri, L. and \vCermák, V.: Borehole temperatures, climate change and pre-observational surface air temperature mean: allowance for hydraulic conditions, Global Planet. Change, 45, 265–276, 2005. Bodri, L. and Dövényi, P.: Climate change of the last 2000 years inferred from borehole temperatures: data from Hungary, Global Planet. Change, 41, 121–133, 2004. Bredehoeft, J. D. and Papadopulos, I. S.: Rates of vertical ground-water movement estimated from the earth's thermal profile, Water Resour. Res., 1, 325–328, 1965. Carslaw, H. S. and Jaeger, J. C.: Conduction of heat in solids, Oxford Univ. Press New York, pp. 386, 1959. Chisholm, T. J. and Chapman, D. S.: Climate change inferred from analysis of borehole temperatures: an example from western Utah. J. Geophys. Res., 97, 14 155–14 175, 1992. Domenico, P. A. and Palciauskas, V. V.: Theoretical analysis of forced convective heat transfer in regional ground-water flow, Geol. Soc. Amer. Bull., 84, 3803–3814, 1973. Ferguson, G., Woodbery, A. D., and Matile, G. L. D.: Estimating deep recharge rates beneath an interlobate moraine using temperature logs, Ground Water, 41, 640–646, 2003. Fetter, C. W.: Applied Hydrology, 2nd Edition, Macmillan New York, pp. 592, 1988. Hansen, J. and Lebedeff, S.: Global trends of measured surface air temperature, J. Geophys. Res., 92, 13 345–13 372, 1987. Harris, R. N. and Chapman, D. S.: Geothermics and climate change: Part 2. Joint analysis of borehole temperature and meteorological data, J. Geophys. Res., 103, 7371–7383, 1998. Karl, T. R., Knight, R. W., and Plummer, N.: Trends in high frequency climate variability in the twentieth century, Nature, 377, 217–220, 1995. Kohl, T.: Paleoclimatic temperature signals – can they be washed out?, Tectonophysics, 291, 225–234, 1998. Kukkonen, I. T. and Joeleth, A.: Weichselian temperatures from geothermal heat flow data, J. Geophys. Res., 108(B3), 2163, doi:10.1029/2001JB001579, 2003. Lewis, T. J. and Wang, K.: Influence of terrain on bedrock temperatures, Global Planet. Change, 98, 87–100, 1992. Menke, W.: Geophysical Data Analysis: Discrete Inverse Theory, Int. Geophys. Ser., 45, Academic Press, San Diego, pp. 289, 1989. Majorowicz, J. A. and Safanda, J.: Measured versus simulated transients of temperature logs – a test borehole climatology, J. Geophys. Eng., 2, 1–8, 2005. Majorowicz, J. A. and Skinner, W. R.: Potential causes of the differences between ground and surface air temperature warming across different ecozones in Alberta, Canada, Glob. Planet. Change, 115, 79–91, 1997. Moberg, A., Jones, P. D., Barriendos, M., Bergström, H., Camuffo, D., Cocheo, C., Davies, T. D., Demarée, G., Martin-Vide, J., Maugeri, M., Rodriguez, R., and Verhoeve, T.: Day-to-day temperature variability trends in 160- to 275-year-long European instrumental records, J. Geophys. Res., 105, 22 849–22 868, 2000. Pasquale, V., Verdoya, M., and Chiozzi, P.: Climate change from meteorological observations and underground temperatures in Northern Italy, Stud. Geophys. Geod., 42, 30–40, 1998. Pasquale, V., Verdoya, M., Chiozzi, P., and Safanda, J.: Evidence of climate warming from underground temperatures in NW Italy, Global Planet. Change, 25, 215–222, 2000. Pasquale, V., Verdoya, M., Chiozzi, P., Bodri, L., and Bellani, S.: Temperature signal in the underground for climate history reconstruction in Italy, Global Planet. Change, 47, 36–50, 2005a. Pasquale, V., Verdoya, M., and Chiozzi, P.: Orographic influence on the central-northern Italy climate from underground temperatures, Croatian Meteorological Journal, 30, 669–671, 2005b. Reiter, M.: Using precision temperature logs to estimate horizontal and vertical groundwater flow components, Water Resour. Res., 37, 663–674, 2001. Reiter, M.: Possible ambiguities in subsurface temperature logs – consideration of groundwater flow and groundsurface temperature change, Pure Appl. Geophys., 162, 343–355, 2005. Serre-Bachet, F.: Middle ages temperature reconstructions in Europe, a Focus on Northeastern Italy, Clim. Change, 26, 213–224, 1994. Verdoya, M., Chiozzi, P., and, Pasquale, V.: Inferring hydro-geothermal parameters from advectively perturbed thermal logs, Int. J. Earth Sci., in press, 2007.