Rapid changes of the ice mass configuration in the dynamic Diablotins ice cave – Fribourg Prealps, Switzerland

Abstract

Abstract. The Gouffre des Diablotins is a deep cave system located in the Swiss Prealps. In 1991, the entrance zone of the cave was almost free of ice. Nevertheless ice volume sharply increased in 1994, plugging almost totally the gallery from the lower entrance. The ice cave have also experience flooded period between 1996 and 2007, and very heterogeneous ice surface morphology and textures have formed. Continuous cave climate measurements initiated in 2009 showed the predominant role of winter atmospheric air conditions to drive both the efficiency of chimney-effect circulation and seasonal modifications of the ice mass. Main part of the ice loss is currently due to sublimation in wintertime.

Talus and its cooling effects on the thermal regime of permafrost: A review

“…84 The lower holes, called the "cold" funnels, 80 which involve the aspiration of cold air, can form even if the snow is thick. 96 von Wakonigg 94 hypothesized that in the warm season the cold air moves downward and is exhausted, and the interior of the talus is heated from top to bottom by the warm air. As the cold air is completely exhausted, the temperature at the bottom of the talus also increases.…”

“…Cold wind blowing from the bottom is a common phenomenon (e.g., 71,72,95,97 ), also known as a "wind hole" 98 and "wind tube". 96 Continuous air exchange with the atmosphere-This theory, proposed by Harris and Pedersen, 75 is a simple extension of the chimney effect. In the cold season, the talus can exchange air with the atmosphere in snow-free areas, thereby allowing the internal temperature to respond rapidly to the external temperature.…”

“…warm air rises through advection and discharges, and the cold air is aspirated from the bottom of talus, leading to cooling of the lower part of the talus. The upper holes, known as funnels, 83 melt holes, 43 and snowmelt windows (when the snow-free area is large), 84,96 are the result of snow being melted by the warm air, but this does not happen when the warm air is below 0 C, which means that these holes may not be visible. 84 The lower holes, called the "cold" funnels, 80 which involve the aspiration of cold air, can form even if the snow is thick.…”

“…89 Additionally, the spatial distribution of snow thickness is not necessarily uniform, possibly being thicker at the bottom and becoming progressively thinner towards the top. 72 The presence of permafrost (e.g., 15,42,64,70,109 ), ground ice (e.g., 71,96,110,111 ), or groundwater (e.g., 82,[112][113][114] ) in talus increases the local thermal conductivity, thereby facilitating heat transfer within the talus. Permafrost is generally distributed at the base of the talus, 16,17,53,62,72,78,115 but can also exist at the top at high altitude.…”