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Climate change on the Colorado Plateau of eastern Utah inferred from borehole temperatures

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Field Value
Title Climate change on the Colorado Plateau of eastern Utah inferred from borehole temperatures
Names Harris, Robert N. (creator)
Chapman, David S. (creator)
Date Issued 1995-04-10 (iso8601)
Note copyrighted by American Geophysical Union
Abstract Temperature profiles from boreholes on the Colorado Plateau of southeastern Utah
have been examined for evidence of climate change. Because these boreholes penetrate layered
sedimentary rocks with different thermal conductivities, Bullard plots (Temperature versus
integrated thermal resistance) are used to estimate background heat flow and surface temperature
intercepts. Reduced temperatures, which represent departures from a constant heat flow
condition, are inverted for a surface ground temperature history at each borehole site using a
singular value decomposition algorithm. Singular value cutoffs are selected by analyzing the
spectral energy and the standard deviation of the model fit to the data as a function of the
number of eigenvalues; solutions are constructed from areas of large spectral energy and a cutoff
where additional eigenvalues fail to improve the solution significantly. The solution is
parameterized in terms of 13 time steps increasing in duration and going back 400 years. Eight
of nine borehole sites indicate between 0.4 and O.8°C (±0.2°C) warming over the past 200 years
with some evidence for accelerated warming in this century; one borehole indicates local cooling
over the same time period. The amplitude of the warming inferred from borehole temperatures is
less than that deduced from analysis of l00-year surface air temperature records at four of the five weather stations surrounding the borehole sites.
Genre Article
Identifier Chapman, D. S., Harris, R. N., (1995) Climate change on the Colorado Plateau of eastern Utah inferred from borehole temperatures, J. Geophys. Res., 100, B4, 6367-6381.

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