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Spatial Distribution and Main Characteristics of Alpine Permafrost from Southern Carpathians, Romania

2016; Springer International Publishing; Linguagem: Inglês

10.1007/978-3-319-32589-7_6

2194-315X

Răzvan Popescu, Alexandru Onaca, Petru Urdea, Alfred Vespremeanu‐Stroe,

Cryospheric studies and observations

The sporadic permafrost specific to the Southern Carpathians is accommodated in three main features at sites with commonly low solar radiation—(i) rock glaciers (>1950 m altitude), (ii) talus slopes, and (iii) shaded rock walls (>2400 m)—with a net prevalence of the former category. Due to its marginal character, the alpine permafrost in Southern Carpathians develops only in the most favorable conditions which consist in cold microclimates imposed by topography (low solar radiation, high altitude), but also in specific ground surface characteristics which promote ground overcooling. Among all, coarse openwork debris is the most favorable land cover type for permafrost development because of the cooling effect it exerts on the underground, especially via air ventilation during cold snow free interval (fall and early winter) and air stratification (low conductivity) under thick snow cover. Because of the large surfaces covered by coarse debris at high altitudes, the granitic massifs of Retezat and Parâng present the most extensive areas with probable permafrost from the Southern Carpathians. Instead, the fine debris specific to crystalline ranges of Făgăraş and Iezer—Păpușa or the small and thin conglomeratic debris of Bucegi massif inhibit nowadays the permafrost formation with very few exceptions. Although most rock glaciers prove to be relict, the present-day climate supports the existence of permafrost into thick and coarse debris (intact rock glaciers and lower sectors of the talus slopes) especially at altitudes higher than 2000 m. The geophysical surveys from granitic rock glaciers situated at 1950–2100 m indicate a thin ( 10–20 m) and sometime supersaturated in ice.