Title Temporal variations in snow facies, and prediction of the metamorphic characteristics and stratigraphy of snow cover [Variabilita temporale delle facies nevose e prevedibilita delle caratteristiche metamorfiche e stratigrafiche del manto nevoso]
Author Motta, L.; Motta, M.
Author Affil Motta, L., Universita di Torino, Dipartimento di Scienze della Terra, Turin, Italy
Source Memorie della Societa Geografica Italiana, 87(2), p.353-364, ; II convegno nazionale A. I. Geo, Turin, Italy, March 28- 30, 2007, V. Agnesi. Publisher: Societa Geografica Italiana, Rome, Italy. ISSN: 0391- 5190
Publication Date 2009
Notes In Italian with English summary. 14 refs. GeoRef Acc. No: 308658
Index Terms precipitation (meteorology); hydrology; meltwater; forecasting; snow; snow cover; statistical analysis; stratification; variations; Alps; Italy--Piemonte; atmospheric precipitation; characterization; Europe; Italy; metamorphism; Mount Jafferau; Piemonte Italy; prediction; Southern Europe; Susa Valley; temporal distribution
Abstract We have arranged the various sedimentary origins of the snow cover (snowfalls, wind and avalanches) and the metamorphism [low (LTG) and high (HTG) thermal gradient, and melt-freeze cycles], obtaining nine facies. Every facies it has a specific mechanical resistance (in relation to avalanches and the attitude to the sky). We have estimated the hypothesis that every locality has of year in year the same sequence of facies. If verified, such hypothesis would open the way to the cartography of the characteristics of the snow cover. We have followed the evolution of the snow cover from 1997 to 1999 in five areas on the Jafferau Mt. (Susa Valley): three to increasing altitude, and two near snow measuring stations. We have observed the following succession of facies. Autumn: facies of direct precipitation--LTG metamorphism, with shallow melting to the lower altitudes. Beginning winter: facies of direct precipitation--LTG metamorphism in the middle part of the profile, facies of direct precipitation--HTG metamorphism to the bottom and, especially to the very high altitudes, near to surface, where melting can be also, because of strong energetic flux. Full winter: more and more facies of direct precipitation-melt-freeze metamorphism replaces that one of direct precipitation-- LTG metamorphism; moreover, to leave from the bottom and surface, slowly the HTG metamorphism involve all the profile, interrupted from episodes of shallow melting that, through percolating processes, can modify the entire profile. Beginning spring: we have observed nearly only facies of direct precipitation-melt-freeze metamorphism and direct precipitation--HTG metamorphism; this last one can arrive to constitute all the profile, or to be limited to single layers. Full spring: only facies of direct precipitation-melt-freeze metamorphism. Both the high inner thermal gradient of the snow cover (caused from the increase of thickness), and the lowering of medium temperature, are cause more and more imbalance with the altitude, between shallow and deep layers: the HTG and melt-freeze processes act strongly therefore more in surface. The main difference between the two periods of observations is the smaller HTG metamorphism in the second period, imputable to the diversities between the two periods in the daily thermic excursion and the total radiation: to February in fact we have recorded one marked reduction in the second period of both factors.
Publication Type conference paper or compendium article
Record ID 65005527