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Air-ground temperature coupling and subsurface propagation of annual temperature signals

Jason E. Smerdon; Henry N. Pollack; Vladimir Cermak; John W. Enz; Milan Kresl; Jan Safanda; John F. Wehmiller

Title:
Air-ground temperature coupling and subsurface propagation of annual temperature signals
Author(s):
Smerdon, Jason E.
Pollack, Henry N.
Cermak, Vladimir
Enz, John W.
Kresl, Milan
Safanda, Jan
Wehmiller, John F.
Date:
Type:
Articles
Department:
Lamont-Doherty Earth Observatory
Volume:
109
Permanent URL:
Book/Journal Title:
Journal of Geophysical Research
Abstract:
Borehole-based reconstructions of ground surface temperature (GST) have been widely used as indicators of paleoclimate. These reconstructions assume that heat transport within the subsurface is conductive. Climatic interpretations of GST reconstructions also assume that GST is strongly coupled to surface air temperature (SAT) on timescales of decades and longer. We examine these two assumptions using records of SAT and subsurface temperature time series from Fargo, North Dakota; Prague, Czech Republic; Cape Henlopen State Park, Delaware; and Cape Hatteras National Seashore, North Carolina. The characteristics of downward propagating annual temperature signals at each site clearly indicate that heat transport can be described as one-dimensional conduction in a homogeneous medium. Extrapolations of subsurface observations to the ground surface yield estimates of annual GST signals and allow comparisons to annual SAT signals. All annual GST signals are modestly attenuated and negligibly phase shifted relative to SAT. The four sites collectively demonstrate that differences between annual GST and SAT signals arise in both summer and winter seasons, in amounts dependent on the climatic setting of each site.
Subject(s):
Atmospheric sciences
Paleoclimate science
Hydrologic sciences
Publisher DOI:
http://dx.doi.org/10.1029/2004JD005056
Item views:
173
Metadata:
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