Transcript Slide - Institute for Applied Geophysics and Geothermal Energy

A Multidisciplinary Analysis
of Climate Change:
Testing Borehole
Paleoclimatology
This research is supported by National Science Foundation Award
ATM - 0318384
W. Gosnold, J. Majorowicz, S. Wood
University of North Dakota
Grand Forks, ND
A critical challenge in global change research is separation
of radiative forcing by anthropogenic greenhouse gases
from radiative forcing due to natural climate variability.
Essential to meeting this challenge is determination of past
climate changes using data from all possible sources, e.g.,
tree rings, ice cores, corals, boreholes, lake and ocean
sediments, for example and then linking the paleoclimate
record with the modern meteorological record.
Multiproxy, borehole, and meteorological records
0.5
Crowley and Lowery 2000 (Ambio 29, 51)
Northern Hemisphere Temperature Reconstruction
Modified as published in Crowley 2000
(Science v289 p.270, 14 July 2000)
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We have initiated a multidisciplinary
project involving five scientists in the US
and two in Canada to test coherence
between:
• ground surface temperatures (GST)
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•
•
reconstructed from borehole T-z profiles
surface air temperatures (SAT)
soil temperatures
solar radiation
Expertise applied in this project includes:
heat flow, microclimatology, solar
radiation, meteorology, and remote
sensing.
The Research Team
Will Gosnold UND
Heat Flow and
Team Leader
Brad Rundquist
UND Remote
Sensing & GIS
Paul Todhunter
UND Microclimate
Jacek Majorowicz
UND Heat Flow
Xiquan Dong UND
Solar Radiation
Shaun Wood UND
Dave Blackwell SMU Jean-Claude Mareschal Julie Popham UND Climate Modeling
QUAM Heat Flow
Meteorology
Heat Flow
Research plan
• Determine heat balance at selected
•
•
borehole sites using the changes in
temperature-depth measurements made
during the past 20 years.
Use AWDN radiation data to determine
radiative component of heat balance.
Synthesize the long-term temperature
record from deep boreholes with the
multi-proxy temperature record and the
meteorological record.
Our Working Hypothesis
Radiative heating and heat exchange
between the ground and the air directly
control the ground surface temperature,
and a time-series of borehole T-z
measurements spanning time periods
when solar radiation, soil and air
temperatures have been recorded will
enable comparison of the thermal energy
stored in the ground to these quantities.
Diurnal and seasonal disturbances of
the geothermal gradient are
approximately sinusoidal and the
temperature at a depth x can be
determined by
T = A e -x√ω/2κ cos (ωt - -x√ω/2κ)
Where T = A e -x√ω/2κ is the amplitude
at depth x and -x√ω/2κ is the phase
retardation of the maxima and minima
of temperature at depth x.
A is the amplitude at the surfae, ω is
angular frequency, and κ is thermal
diffusivity.
Diurnal signals damp out in the upper
meter and annual signals damp out
within the upper 20 to 30 m.
The effect of a 2 degree
shift in mean annual
surface is shown for
three different periods:
Red curves: one year
Green curves: ten years
Blue curves: 100 years
• The ground is an excellent filter for
temperature signals.
• Short period (high frequency)
signals are removed.
• Long period signals that may have
been obscured in the “noise” are
revealed.
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Ground filtered Winnipeg SAT
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Degrees
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Surface
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10 m
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20 m
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Date
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2010
Diffusion of Surface Temperature
into the Subsurface
Synthetic T-z profiles at different
times from GHCN for latitudes
60N- 90N
Tz profiles
from 46N
to 50N
within
longitude
96W to
104W
GSTH binned by latitude in the North American
Great Plains supports predictions of CO2 models
Example of surface warming observed in 3
boreholes in North American Great Plains
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Deg C
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Landa 2002
Landa 1995
Landa 1984
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M inot 2002
M inot 1995
M inot 1984
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Glenburn 2002
Glenburn 1995
Glenburn 1984
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Meters
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Deg C
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Landa heat flux model
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1995
10 mW/m^2
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Meters
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Subsurface Heating at Wall, South Dakota
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Depth (m)
Matching change in borehole Tz with AWDN stations
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Borehole
CottonWood
Wasta
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Interior
Rapid
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Rapid2
Deg.
Elm Springs
Red Ow l
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Plainview
Milesville
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Midland
Longvalley
Procupine
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Manderson
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Depth (m )
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Monthly Air Temperatures Showing
no Apparent Pattern or Trend
When projected into the subsurface
the air temperature data reveal the
11 yr solar cycle
Air and Subsurface combined
Global Temperature Anomaly
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Lean, J.. 2004. Solar Irradiance Reconstruction. IGBP PAGES/World
Data Center for Paleoclimatology Data Contribution Series # 2004-035.
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.
Wm
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Crowley, T.J., 2000, Causes of Climate Change Over the Past 1000 Years, IGBP
PAGES/World Data Center for Paleoclimatology Data Contribution Series #2000-045.
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.
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Sol.Be10/Lean.splice
GHG
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TOTAL
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Observed and synthetic Tz profiles based on solar
flux
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Deg.
50 mW/m^2/100y
60 mW/m^2/100y
45 mW/m^2/150y
Observed Tz
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Depth (m)
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Conclusions
• Repeat temperature-depth (T-z)
measurements made at different times in
a span of one or more decades in the
same borehole can provide information
that may lead to better understanding of
the forcing mechanisms of climate change.
Conclusion
• If coherence between energy storage, solar
radiation, GST, SAT and multi-proxy temperature
data can be discerned for a one or two decade
scale, synthesis of these data over the past
several centuries may enable us to separately
determine anthropogenic and natural forcing of
climate change. Our current research provides a
comprehensive test of this hypothesis.
• This research is supported by National Science Foundation
Award ATM - 0318384