Cobertura nival y distribución de las temperaturas en el suelo en las cumbres de la Sierra de Guadarrama

Air and ground temperatures were monitored from 2002 - 2007 at the summit area of Alto de las Guarramillas (2258 m; 40º 47' 10'' N and 3º 58' 46'' W) in the central sector of Sierra de Guadarrama, a mountain range located 50 km from Madrid. Air temperature was recorded at the summit while ground temperature was monitored at 3 locations, differentiated by the permanence of snow cover: the summit, inside a snow hollow, known as Ventisquero de la Condesa, located on the east side of the summit and the pronival sector of this hollow. During the summer, ground temperatures were uniform for all three control points, and showed symmetrical changes with the air temperature. During the period of snow cover, ground temperature varied widely among the sample sites as influenced by snow thickness and, particularly, snow cover duration. It is uncertain as to whether these variations could be related to variations in air temperature. Snow thickness and snow cover duration are factors that directly affect phase changes in ground water content, which subsequently influences geomorphologic processes and plant cover. Snow cover duration is a crucial factor, because it can markedly alter ground temperature in a distance of only a few meters