The Belvedere Glacier elevation change between 1951 and 2023

Abstract

This study describes and analyses elevation changes in the debris-covered tongue of the surge-type Belvedere Glacier (Western Italian Alps) between 1951 and 2023 using remote sensing data, including historical aerial photographs, Lidar and drone acquisitions. High-resolution digital surface models from 1951, 2009 and 2023 enabled detailed observation of the spatially heterogeneous patterns of change caused by debris cover, avalanches, a surge-type event, supraglacial meltwater, and glacial lake outburst floods in the context of global warming. In the period of 1951–2009, the mean rate of downwasting was quantified as 0.24 metres per year (14 metres in total), ranging from −83.5 to 32.2 metres. During the second observation period from 2009 to 2023, the mean downwasting rate was estimated to be 1.8 metres per year (25 metres in total), varying from −73.9 to 26.9 metres. The 2001–2002 surge-type event, meltwater streams and supraglacial lakes are considered to be the main drivers forcing elevation changes and shaping its spatial variation and surface structures. In general, the changes in the glacier have accelerated between 2009 and 2023. This paper demonstrates the high potential of differenced digital surface models with high spatial resolution to detect the processes of glacier dynamics in high detail.