HR: 1020h
AN: PP52A-0650    [Abstracts]
TI: Comparison Between Different Approaches for Simultaneous Inversion of Temperature Depth Profiles Measured in Boreholes: Analysis of Two Data Sets in central Canada.
AU: * Chouinard, C
EM: cchouin@olympus.geotop.uqam.ca
AF: GEOTOP-UQAM-McGill University of Quebec at Montreal, POB 8888, sta. "downtown", Montreal, QC H3C3P8 Canada
AU: Mareschal, J
EM: jcm@olympus.geotop.uqam.ca
AF: GEOTOP-UQAM-McGill University of Quebec at Montreal, POB 8888, sta. "downtown", Montreal, QC H3C3P8 Canada
AB: We have used two different inversion techniques, singular value decomposition and Tikhonov regularization, to infer the ground surface temperature history (GSTH) from temperature depth profiles measured in Manitoba-Saskatchewan and in Western Ontario. For each data set, we have first selected and inverted the profiles that were not affected by obvious non climatic effects (water flow, proximity to a lake, topography, change in vegetation or recent forest fires, etc.). We have thus selected 21 profiles out of 76 in Manitoba and Saskatchewan, and 23 out of 36 in western Ontario. Then we have inverted the entire data set in each region. For all the data sets analyzed, the inversions are much more stable with Tikhonov regularization than with singular value decomposition which always causes oscillations in the GSTH. Nevertheless, both methods show very similar trends. In both regions, the GSTH's show recent (200 years) warming after a colder period. There are no significant differences between the GSTH's obtained by inversion of the entire data sets and the GSTH's from selected profiles. It thus appears that "non-climatic" perturbations of the temperature profiles do not have a systematic effect on the climate reconstruction.
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4914 Continental climate records
DE: 8130 Heat generation and transport
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005