Climate of the Past www.clim-past.net 1814-9324 1814-9332 3 2 2007 10.5194/cp-3-297-2007 http://www.clim-past.net/3/297/2007/ http://www.clim-past.net/3/297/2007/cp-3-297-2007.html http://www.clim-past.net/3/297/2007/cp-3-297-2007.pdf 297 313 2007-06-11 Selection of borehole temperature depth profiles for regional climate reconstructions C. Chouinard J.-C. Mareschal jcm@olympus.geotop.uqam.ca GEOTOP-UQAM-McGill, Centre de Recherche en Géochimie et en Géodynamique, Univ. du Québec à Montréal, Canada Borehole temperature depth profiles are commonly used to infer time variations in the ground surface temperature on centennial time scales. We compare different procedures to obtain a regional ground surface temperature history (GSTH) from an ensemble of borehole temperature depth profiles. We address in particular the question of selecting profiles that are not contaminated by non climatic surface perturbations and we compare the joint inversion of all the profiles with the average of individual inversions. Very few profiles of the Canadian data set meet the selection criteria (e.g. only 13 out of 73 profiles in Manitoba and Saskatchewan were retained). We show that the resolution and the stability of the inversion of selected profiles are much improved over those for a complete data set. When profiles have been selected, the average GSTH of individual inversions and the GSTH of the joint inversion are almost identical. This is not observed when the entire data set is inverted: the average of individual inversions is different from the joint inversion. We also show that the joint inversion of very noisy data sets does not improve the resolution but, on the contrary, causes strong instabilities in the inversion. When the profiles that are affected by noise can not be eliminated, averaging of the individual inversions yields the most stable result, but with very poor resolution. Beltrami, H.: Surface heat flux histories from inversion of geothermal data: Energy balance at the Earth's surface, J. Geophys. Res., 106, 21 979–21 994, \doi10.1029/2000JB000065, 2001. Beltrami, H. and Mareschal, J.-C.: Recent warming in eastern Canada inferred from geothermal measurements, Geophys. Res. Lett., 18, 605–608, 1991. Beltrami, H. and Mareschal, J.-C.: Ground temperature histories for central and eastern Canada from geothermal measurements: Little ice age signature, Geophys. Res. Lett., 19, 689–692, 1992. Beltrami, H. and Mareschal, J.-C.: Resolution of ground temperature histories inverted from borehole temperature data, Global Planet. Change, 11, 57–70, 1995. Beltrami, H., Jessop, A M., and Mareschal, J.-C.: Ground temperature histories in eastern and central Canada from geothermal measurements: evidence of climatic change, Global Planet. Change, 19, 167–184, 1992. Beltrami, H., Cheng, L., and Mareschal, J.-C.: Simultaneous inversion of borehole temperature data for determination of ground surface temperature history, Geophys. J. Int., 129, 311–318, 1997. Blackwell, D D., Steele, J L., and Brott, C A.: The terrain effect on terrestrial heat flow, J. Geophys. Res., 85, 4757–4772, 1980. Bodri, L. and Cermak, V.: Reconstruction of remote climate change from borehole temperatures, Global Planet. Change, 15, 47–57, 1997. Carslaw, H S. and Jaeger, J C.: Conduction of Heat in Solids, Oxford University Press, New-York, second edn., 1959. Cermak, V.: Underground temperature and inferred climatic temperature of the past millenium, Palaeogeogr. Palaeocl., 10, 1–9, 1971. Clauser, C. and Mareschal, J.-C.: Ground temperature history in central Europe from borehole temperature data, Geophys. J. Int., 121, 805–817, 1995. Gosselin, C. and Mareschal, J.-C.: Recent warming in northwestern Ontario inferred from borehole temperature profiles, J. Geophys. Res.-Solid Earth, 108, \doi10.1029/2003JB002447, 2003. Guillou-Frottier, L., Mareschal, J.-C., and Musset, J.: Ground surface temperature history in central Canada inferred from 10 selected borehole temperature profiles, J. Geophys. Res., 103, 7385–7398, \doi10.1029/98JB00021, 1998. 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.: Mid-Latitude (30\deg-60\degN) climatic warming inferred by combining borehole temperatures with surface air temperatures, Geophys. Res. Lett., 28, 747–750, \doi10.1029/2000GL012348, 2001. Hartman, A. and Rath, V.: Uncertainties and shortcomings of ground surface temperature histories derived from inversion of temperature logs, J. Geophys. Eng., 4, 299–311, \doi10.1088/1742-2132/2/4/S02, 2005. Huang, S., Pollack, H N., and Shen, P Y.: Temperature trends over the past five centuries reconstructed from borehole temperatures, Nature, 403, 756–758, 2000. Jackson, D D.: Interpretation of inaccurate, insufficient, and inconsistent data, Geophys. J. R. Astron. Soc., 28, 97–110, 1972. Jessop, A M.: The distribution of glacial perturbation of heat flow in Canada, Can. J. Earth Sci., 8, 162–166, 1971. Jones, P D., Wigley, T M L., and Wright, P B.: Global variations between 1861 and 1984, Nature, 322, 430–434, 1986. Jones, P D., New, M., Parker, D E., Martin, S., and Rigor, I G.: Surface air temperature and its changes over the past 150 years, Rev. Geophys., 37, 173–200, \doi10.1029/1999RG900002, 1999. Lachenbruch, A H. and Marshall, B V.: Changing climate: Geothermal evidence from permafrost in the Alaskan Arctic, Science, 234, 689–696, 1986. Lanczos, C.: Linear Differential Operators, D. Van Nostrand, Princeton, N.J., 1961. Lewis, T J.: The effect of deforestation on ground surface temperatures, Global Planet. Change, 18, 535–538, 1998. Majorowicz, J A., Safanda, J., Harris, R N., and Skinner, W R.: Large ground surface temperature changes of the last three centuries inferred from borehole temperatures in the Southern Canadian Prairies, Saskatchewan, Global Planet. Change, 20, 227–241, 1999. Mareschal, J C., Jaupart, C., Gariépy, C., Cheng, L Z., Guillou-Frottier, L., Bienfait, G., and Lapointe, R.: Heat flow and deep thermal structure near the southeastern edge of the Canadian Shield, Can. J. Earth Sci., 37, 399–414, 2000. Mareschal, J C., Jaupart, C., Rolandone, F., Gariépy, C., Fowler, C. M R., Bienfait, G., and Carbonne, C.: Heat flow, thermal regime, and rheology of the lithosphere in the Trans-Hudson Orogen, Can. J. Earth Sci., 42, 517–532, 2005. Menke, W.: Geophysical Data Analysis: Discrete Inverse Theory, no 45 in International Geophysical Series, Academic Press, San Diego, 1989. Misener, A D. and Beck, A E.: The measurement of heat flow over land, in: Methods and Techniques in Geophysics, edited by: Runcorn, S K., Wiley-Interscience, New-York, pp 11–61, 1960. Nielsen, S B. and Beck, A E.: Heat flow density values and paleoclimate determined from stochastic inversion of four temperature-depth profiles from the Superior Province of the Canadian Shield, Tectonophysics, 164, 345–359, 1989. Parker, R L.: Geophysical Inverse Theory, Princeton University Press, Princeton, New Jersey, 1994. Perry, H. K C., Jaupart, C., Mareschal, J C., and Bienfait, G.: Crustal heat production in the Superior province of the Canadian Shield and in North America, inferred from heat flow data, J. Geophys. Res., 111, B04 401, \doi10.1029/2005JB003893, 2006. Pinet, C., Jaupart, C., Mareschal, J.-C., Gariepy, C., Bienfait, G., and Lapointe, R.: Heat flow and structure of the lithosphere in the eastern Canadian shield, J. Geophys. Res., 96, 19 941–19 963, 1991. Pollack, H N., Shen, P Y., and Huang, S.: Inference of ground surface temperature history from subsurface temperature data: Interpreting ensembles of temperature logs, Pure Appl. Geophys., 147, 537–550, 1996. Pollack, H N., Huang, S., and Shen, P Y.: Climate change records in subsurface temperatures: A global perspective, Science, 282, 279–281, 1998. Press, W H., Teukolsky, W T., Vetterling, W T., and Flannery, B P.: Numerical Recipes in Fortran. The Art of Scientific Computing, Cambridge University Press, Cambridge, UK, 1992. Shen, P Y. and Beck, A E.: Least squares inversion of borehole temperature measurements in functional space, J. Geophys. Res., 96, 19 965–19 979, 1991. Tikhonov, A N. and Arsenin, V Y.: Solution of ill posed problems, Wiley, New-York, 1977. Vasseur, G., Bernard, P., Van de Meulebrouck, J., Kast, Y., and Jolivet, J.: Holocene paleotemperatures deduced from geothermal measurements, Palaeogeogr. Palaeocl., 43, 237–259, 1983. Wang, K.: Estimation of ground surface temperatures from borehole temperature data, J. Geophys. Res., 97, 2095–2106, 1992. Wang, K., Lewis, T J., Belton, D S., and Shen, P Y.: Differences in recent ground surface warming in eastern and western Canada: Evidence from borehole temperatures, Geophys. Res. Lett., 21, 2689–2692, 1994.