Differences between repeated borehole temperature logs in the southern Canadian Prairies-validating borehole climatology
J. Majorowicz1,4, W. Skinner2, J. Safanda3, and W. Gosnold41Northern Geothermal, 105 Carlson Close, Edmonton, Alberta, T6R 2J8, Canada 2Climate Research Division, Environment Canada, Toronto, Ontario, M3H 5T4, Canada 3Geophysical Institute, Prague, Czech Republic 4University of North Dakota, Northern Plains Climate Research Centre, Grand Forks, ND, USA
Received: 25 Oct 2006 – Discussion started: 07 Nov 2006
Abstract. Temperature-depth (T-z) profiles from twenty-four shallow boreholes of less than 250 m in depth located in flat, semi-arid areas of the southern Canadian Prairie Provinces initially measured in the late 1980's and early 1990's and repeated between 2004 and 2006 show strong ground surface temperature (GST) warming signatures. GST changes of 0.1–0.2°C, and 0.4°C, are observed between the measurements for the shorter (decade) and longer (two decades) time spans, respectively. Borehole sites with repeated temperature logs are selected to demonstrate that multiple T-z profiles provide general agreement between GST warming and observed surface air temperature (SAT) warming measured at nearby historical climate stations. A comparison of measured changes from repeated temperature logs with those simulated from SAT forcing demonstrates the influence of SAT on the observed deviation of temperature with depth despite variations in snow cover. Repeated borehole measurements from the northern Great Plains of the USA also identify a similar positive temperature change but of lower magnitude. Temperature changes since 1900 in the southern Canadian Prairies and the adjoining northern Great Plains of the USA, as derived from the functional state inversion (FSI) of deeper borehole logs, average 2.5°C but show a strong latitudinal gradient.
Majorowicz, J., Skinner, W., Safanda, J., and Gosnold, W.: Differences between repeated borehole temperature logs in the southern Canadian Prairies-validating borehole climatology, Clim. Past Discuss., 2, 1075-1104, doi:10.5194/cpd-2-1075-2006, 2006.