ORIGINAL PAPER Evidence of climate change within the Adamello Glacier of Italy Daniele Bocchiola & Guglielmina Diolaiuti Received: 31 January 2009 / Accepted: 17 July 2009 / Published online: 14 August 2009 # Springer-Verlag 2009 Abstract We analyze a daily series of rainfall, snowfall, air temperature, and snow water equivalent at fixed dates from 40 high-altitude stations on the Adamello Glacier area (Italian Alps), for the period 1965–2007. Purposes of the study are (1) to investigate significant variation in time, (2) to evaluate effect of temperature changes on cryospheric water cycle, and (3) to evaluate underlying climate patterns and the most significant variables for climate change studies. We detect the presence of a trend using linear regression, moving window average and Mann Kendall test. Linear dependence of water related variables on temperatures is assessed. We find substantially unchanged atmospheric water input along with increasing temperature and rainfall, decreasing snowfall and snow water equivalent at thaw, and shortening of snow cover extent and duration. We carry out a principal components analysis which highlights patterns of precipitation distribution resulting from local temperature and external forcing. A set of the most representative variables for climate and glacier studies is then assessed. A comparison with three nearby Southern Alpine glacierized areas in Italy and Switzerland shows substantial agreement. In spite of the relative shortness of the series, the results here are of interest and can be used as a benchmark for climate change impact assessment for the Adamello Glacier area and southern Alps. 1 Introduction The recognized evidence of global warming requires assessment of its impact on the hydrological cycle and water resource distribution within the mountain areas in temperate regions, and upon the Alpine environment (e.g. Barry 2003; Barnett et al. 2005). In Italian mountain ranges, the importance of water from the Alps has emerged clearly during the latest dry summers, most notably in year 2003, when it saved most of the tributaries of the Po river from the severest droughts, and evidence is raising of ongoing variability of European Alpine water resources due to transient climate change (Rohrer et al. 1994; Beniston 1997; Laternser and Schneebeli 2003). Snow cover extent, duration and dynamics influence vegetal and animal biota in Alpine areas (e.g. Erschbamer 1989; Gottfried et al. 1999; Theurillat and Guisan 2001; Kulakowski et al. 2006), and freshwater availability from cryosphere during spring and summer regulates the hydro- logical cycle of Alpine basins and lowlands downstream (e.g. Coughlan and Running 1997, McGlynn et al. 1999, Beniston et al. 2003). Transient climate change influences water budget (e.g. Rohrer et al. 1994; Beniston 1997; Singh and Kumar 1997; Braun et al. 2000; Spreitzhofer 2000; Laternser and Schneebeli 2003; Schneeberger et al. 2003), spring and winter stream flows (e.g. Braun et al. 2000; Liu et al. 2003), and dynamics of natural water bodies (e.g. Stefan and Fang 1997). The hydrology of Alpine basins was studied in different ways. The amount of snow water equivalent (SWE) cumulated in snowpack and available at spring thaw has been investigated (e.g. Bohr and Aguado 2001), and daily D. Bocchiola (*) Deparment I.I.A.R., Politecnico di Milano, C.I.M.I. Section, 32 Leonardo da Vinci Sq., 20133 Milano, Italy e-mail: daniele.bocchiola@polimi.it G. Diolaiuti Earth Science Department, Università degli Studi di Milano, Mangiagalli 34, Milano, Italy e-mail: guglielmina.diolaiuti@unimi.it Theor Appl Climatol (2010) 100:351–369 DOI 10.1007/s00704-009-0186-x