Abstract
Abstract. The variability of glacier response to atmospheric temperature rise in different topo-climatic settings is still a matter of debate. To address this question in the Central Italian Alps, we compile a post-LIA (Little Ice Age) multitemporal glacier inventory (1860–1954–1990–2003–2007) along a latitudinal transect that originates north of the continental divide in the Livigno Mountains and extends south through the Disgrazia and Orobie ranges, encompassing continental-to-maritime climatic settings. In these sub-regions, we examine the area change of 111 glaciers. Overall, the total glacierized area has declined from 34.1 to 10.1 km2, with a substantial increase in the number of small glaciers due to fragmentation. The average annual decrease (AAD) in glacier area has risen by about 1 order of magnitude from 1860–1990 (Livigno: 0.45; Orobie: 0.42; and Disgrazia: 0.39 % a−1) to 1990–2007 (Livigno: 3.08; Orobie: 2.44; and Disgrazia: 2.27 % a−1). This ranking changes when considering glaciers smaller than 0.5 km2 only (i.e., we remove the confounding caused by large glaciers in Disgrazia), so that post-1990 AAD follows the latitudinal gradient and Orobie glaciers stand out (Livigno: 4.07; Disgrazia: 3.57; and Orobie: 2.47 % a−1). More recent (2007–2013) field-based mass balances in three selected small glaciers confirm post-1990 trends showing the consistently highest retreat in continental Livigno and minimal area loss in maritime Orobie, with Disgrazia displaying transitional behavior. We argue that the recent resilience of glaciers in Orobie is a consequence of their decoupling from synoptic atmospheric temperature trends, a decoupling that arises from the combination of local topographic configuration (i.e., deep, north-facing cirques) and high winter precipitation, which ensures high snow-avalanche supply, as well as high summer shading and sheltering. Our hypothesis is further supported by the lack of correlations between glacier change and glacier attributes in Orobie, as well as by the higher variability in ELA,sub>0 positioning, post-LIA glacier change, and interannual mass balances, as we move southward along the transect.
Highlights
Mountain glaciers are prominent players in the hydrologic and geomorphic functioning of glacierized drainage basins
We argue that the recent resilience of glaciers in Orobie is a consequence of their decoupling from synoptic atmospheric temperature trends, a decoupling that arises from the combination of local topographic configuration and high winter precipitation, which ensures high snow-avalanche supply, as well as high summer shading and sheltering
Median ELA0 (Fig. 4) and clear-sky radiation mirror the spatial variability of local relief in that they slightly increase from the interior, plateau-like topography of Livigno (2833 m a.s.l.; 176 W m−2) to the Disgrazia massif (2890 m a.s.l.; 210 W m−2) and drop abruptly in the Orobie range (2517 m a.s.l.; 145 W m−2)
Summary
Mountain glaciers are prominent players in the hydrologic and geomorphic functioning of glacierized drainage basins. They are effective agents of landscape evolution (Montgomery, 2002; Brardinoni and Hassan, 2006) and modulate present hydrologic, sedimentary, and geochemical fluxes along the receiving fluvial systems. Composite glacier sensitivity to recent and ongoing climate changes has been reported through models based on empirical glacier mass balances from selected case studies (Oerlemans and Fortuin, 1992). Low-elevation glaciers under maritime conditions, with high accumulation and mass turnover, would display higher sensitivity to climate fluctuations compared to their counterparts located in drier, continental settings.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
