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Friday, October 5, 2012

There Core of the Problem - The Abysmal Depths

Updated 10/8

Climate has limits.  One of the main limits is the temperature of sea water in the abysmal depths.  In the above plot, M16722 is the Tropical Atlantic bottom water temperature derived from delta 18O and TR 163-31P is the tropical Pacific bottom water temperature by the same method, provided by Martin et al.(1).
The Galapagos curve is SST provided by Lea et al. (2)  Comparing the Abysmal water(SBT) to the Surface water (SST) temperatures there is an inverse relationship.

Clarification:  The Chart above has delta18O which has an inverse relationship with temperature.  This creates confusion when I used the term inverse relationship.  The relationship I am referring to is between SST and BWT after the perturbation of the change from glacial to interglacial.  In Phase to out of phase transitions would be better than inverse relationship.

This chart should be easier to understand.  Since there were questions on the P. Martin 2002 data and how I manipulated it, here is another post explaining things.

The initial shock of a perturbation drives the SST up and the SBT down.  Both decay to "normal" at different rates.  In this slice of history, approximately 40,000 years was required for the SST to "settle" ~4 C while the SBT required ~36,000 years to "settle" from ~1C depressed temperatures.  It took approximately 4,000 years for the SBT and the SST to reach a "conditional" equilibrium where both "settled" in unison.

These delays and decay periods are probably the most difficult issues with climate to resolve.  With a slow rate of change in "unforced" conditions, the return of SBT to "normal"  would have approximately a 1.25C impact on climate.  Since the decay is not perfectly "dampened", overshoots of "normal" would produce climate oscillations or "unforced variations".  Should these natural, "unforced variations" be out of phase with the Milankovic cycles, not each Milankovic cycle peak or valley would produce the same response in the climate system.
So for the skeptics in the crowd, that is just about as simple as I can make this particular point about non-linear fluid dynamics, Thermal Inertia is a Bitch.

( 1) Martin, P., et al.  2006.
Atlantic/Pacific Quaternary Benthic Foraminifer Mg/Ca Paleotemperature Data.
IGBP PAGES/World Data Center for Paleoclimatology
Data Contribution Series # 2006-114.
NOAA/NCDC Paleoclimatology Program, Boulder CO, USA.

(2) Lea, D.W., et al. 2006.
Galápagos TR163-22 Foraminiferal d18O and Mg/Ca Data and SST Reconstruction.
IGBP PAGES/World Data Center for Paleoclimatology
Data Contribution Series # 2006-090.
NOAA/NCDC Paleoclimatology Program, Boulder CO, USA.

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