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R. D. Lorenz, J. I. Lunine, P. G. Withers (LPL, U. Arizona), C. P. McKay (NASA Ames)
Voyager 1 IRIS observations suggest that Titan's high latitude temperatures are about 3K lower than those at low latitudes. Titan is a small, slowly rotating body with an atmosphere denser than Earth's, and all of these factors suggest meridonal heat transport should be more efficient on Titan than on Earth. Yet were this the case, the temperature contrasts would be far less, around 0.01K.
One possibility is that there is not a 2-3K temperature contrast and that the 530 cm-1 IRIS brightness temperatures are sensing a stratospheric contribution. The other possibility is that conventional parameterizations of heat transport are incorrect or incomplete : Stevenson and Potter suggested condensation processes may buffer or 'pin' polar temperatures.
Some support for the latter hypothesis comes from a principle postulated for the Earth's climate by Paltridge in 1975, namely that the planet's complex fluid motions organize themselves to maximize the production of entropy. This principle would suggest a transport efficiency some 2 orders of magnitude weaker than Earth, producing temperatures exactly as indicated.
Cassini will resolve the debate with RADAR microwave radiometry, CIRS and radio occultations at a range of latitudes.
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