During last years several studies have been carried out to observe the evolution of the growing pattern of water ice crystals, colloquially known as snowflakes. The entropy change involved in the phase transition between both states could be easily measured with standard techniques and several other variables can be traced, as the Gibbs energy and, specially, the enthalpy. It has been already proved that these variables show a significant change in behavior since colder season is approaching (Mormont et al. 296) but this change is not only noticed over time but also regarding the position where the experiment is held, specifically, latitude. Several authors (see Tarly et al. 298 and references therein) found higher freezing speed, more complex structures and lower enthalpies when experiments where conducted at higher latitudes, i.e. towards North, but no specific trend or empirical law has been found until now.
We carried out several coordinated experiments at different locations over the same longitudinal position, in order to minimise the number of variables, tracing the thermodynamic properties of water going through a freezing process. We repeat the experiment coordinately every seven days up to a total of 343 days to follow the temporal evolution of the results. We found that enthalpy, H, needed to form a crystal scales like a power-law with time with a parameter of ~1.2+-0.3. Also, the heat capacity remains constant over time but rises with latitude as C=a·L^b, where C is the the heat capacity, L is the latitude measured from The Wall in stereoradians, and a and b are the inferred parameters to which we found values of a = 1.3+-0.6 [st ·J/K] and b = 1.06+-0.02.
These results will be crucial when trying to understand winter-related processes and how White Walkers coming is affecting global climate change.