Snowfall phases in analysis of a snow cover in Hornsund, Spitsbergen

Conditions influencing formation of a snow cover in southern Spitsbergen in Homsund during the winters 1988/1989 and 1989/1990 are presented. Winter snow cover consists of several overlaid layers which correspond to particular snowfall phases, distinguished on the basis of analysis of occurrence of winter precipitation and development of a snow cover in numerous snow pits. Five snowfall phases during the winter 1988/1989 and three during the winter 1989/1990 were determined. A genetic classification, including specific features of a snow cover in Spitsbergen, was applied to describe snow layers in pits. The classification covers metamorphic changes of snow: dry metamorphosis, wet metamorphosis without freezing, wet metamorphosis with freezing, and aeolian metamorphosis. Precipitation, strong winds, and winter thaws are the factors which mostly influence formation of a snow cover in the Hornsund region. Most winter precipitation is connected with inflow of relatively warm air masses from the Norwegian Sea. Short term winter thaws which occur afterwards, result in formation of a characteristic ice-crust on a snow cover. The ice-crust layer protects a snow cover against deflation. It is also a marker band which enables dating of snow. Ice crust layers are almost always the borders between particular snowfall phases. Strong winds (V > 8 m/s) significantly transform a surface layer of snow. Snow deflation, which is locally quite intensive, occurs mainly at seashore plains, mountain ridges and convex slopes

The thermal condition of the active layer in the permafrost at Hornsund, Spitsbergen

Ground temperature variations have been analysed to the depth of 160 cm,with respect to meteorological elements and short−wave radiation balance. The database of the ground temperature covers a thirteen month−long period (May 1992 – June 1993), which in− cluded both the seasons of complete freezing of the ground and thaw. Special attention has been given to the development of perennial permafrost and its spatial distribution. In summer, the depth of thawing ground varied in different types of ground—at the Polish Polar Station, this was ca. 130 cm. The ground froze completely in the first week of October. Its thawing started in June. The snow cover restrained heat penetration in the ground, which hindered the ground thawing process. Cross−correlation shows a significant influence of the radiation bal− ance (K*) on the values of near−surface ground temperatures (r2 = 0.62 for summer)

Distribution of snow accumulation on some glaciers of Spitsbergen

We describe the spatial variability of snow accumulation on three selected gla− ciers in Spitsbergen (Hansbreen, Werenskioldbreen and Aavatsmarkbreen) in the winter seasons of 1988/89, 1998/99 and 2001/2002 respectively. The distribution of snow cover is determined by the interrelationships between the direction of the glacier axes and the domi− nant easterly winds. The snow distribution is regular on the glaciers located E−W, but is more complicated on the glaciers located meridionally. The western part of glaciers is more predisposed to the snow accumulation than the eastern. This is due to snowdrift intensity. Statistical relationships between snow accumulation, deviation of accumulation from the mean values and accumulation variability related to topographic parameters such as: alti− tude, slope inclination, aspect, slope curvature and distance from the edge of the glacier have been determined. The only significant relations occured between snow accumulation and altitude (r = 0.64–0.91)

Zmienność temperatury u spodu sezonowej pokrywy śnieżnej w strefie sporadycznego występowania wieloletniej zmarzliny w Tatrach

Pokrywa śnieżna ze względu na swoją niską przewodność termiczną chroni podłoże przed zimową utratą ciepła. Natomiast jej wysokie albedo i entalpia przejścia fazowego ograniczają przepływ ciepła z atmosfery do gruntu podczas roztopów (Zhang 2005). W zależności od bilansu ciepła powierzchni gruntu wieloletnia zmarzlina może rozwijać się zarówno u spodu niskiej, jak i wysokiej sezonowej pokrywy śnieżnej (m.in. Goodrich 1982). W tym ostatnim przypadku przyczyną może być także zimowa cyrkulacja powietrza wewnątrz stoków usypiskowych i lodowców gruzowych (m.in. Delaloye, Lambiel 2005)