Melting of surface water ice seasonally deposited from atmosphere in Martian gullies - can it be directly observed?

We consider when and how much liquid water under present climate is possible within the gullies discovered on the surface of many of the Martian craters. Most of the inner parts of these craters are shadowed during large fraction of the year allowing for condensation of atmospheric water vapor. The model includes seasonal condensation and sublimation cycle of both CO_2 and H_2O. It also includes an approximate topography of the gullies as well as the inclination of the slope where they appear. We have found, that water ice seasonally condensed on the walls of gully-like troughs can undergo transition to the liquid phase after complete sublimation of CO_2 ice. The amount of produced liquid water is most likely to be very small, about 0.20 kg m^-2. In any particular place water is likely to remain liquid for only few hours, but under certain conditions may appear during several consecutive sols. Small amount of liquid water predicted by our simulations is not enough to cause any flow, but may be important for chemical processes within the surface material and should be detectable by in-situ observations as well as by spectrometry and temperature measurements of high enough spatial resolution.