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Alex writes:
Uh, I'm sure that Mellon and Phillips are aware of the "recent TES measurements." In fact, Mellon has co-authored a paper using TES data:

Jakosky, B. M. ; Mellon, M. T. ; Kieffer, H. H. ; Christensen, P. R. ; Varnes, E. S. ; Lee, S. W. 1999
The thermal inertia of Mars from the Mars Global Surveyor Thermal Emission Spectrometer
J. Geophys. Res. Vol. 105 , No. E4 , p. 9643

At any rate, refer to my post below regarding TES and bolometric measurements during periods of high dust loading (i.e., southern spring and summer), which was the case over the southern hemisphere as depicted in the graphical plot at

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According to Holger Isenberg who wrote to one of the scientists involved with the TES instrument, this data has not been published yet. Mellon and Phillips may not have been aware that above 0 temperaures can be reached this far south. During the news conference announcing the gullies, all the participants made reference to the idea that the temperatures were too cold at these sites. I presume they were not aware of these measurements at the time or the data was not available then.

The idea of the gully formation is that they would be formed specifically when the temperatures reached the range for liquid water to form. One effect of high dust content during a particular period is that if it covered the southern ice cap it could then increase the seasonal melting of the ice which would then increase the atmospheric pressure on Mars. This would make it more likely for water to remain stable at that time.

Bob Clark