Lukáš Brodský

Temperature-dependent changes in residual shear strength are important for slope stability, landslide reactivation, and thermally loaded geotechnical structures. Although this response is controlled by mineral composition, there is no clear method for extending laboratory results to larger areas. This study combines temperature-controlled ring shear testing with short-wave infrared (SWIR) spectroscopy for eight mixtures of quartz-rich sand, kaolin, and bentonite. The specimens were tested at normal stresses of 50, 100, and 150 kPa and subjected to heating-cooling cycles between 20 and 80 °C. Sand and kaolin rich mixtures showed little change, whereas mixtures containing at least 50% bentonite showed clear heating-induced strengthening. For pure bentonite, the residual friction angle increased from 6.18° to 9.02°, corresponding to Δϕr=+2.84°. The SWIR spectra distinguished clay-bearing from clay-free mixtures using the absorption feature near 2209 nm and differentiated high-activity from low-activity clays using the feature near 1912 nm. Partial least-squares regression was then used to relate the spectra to residual friction angle. Finally, the spectral data were interpolated across a sand–kaolin–bentonite ternary space and combined with the laboratory results to map Δϕr. The study provides a first step toward mapping mineral-dependent thermal changes in soil strength.

1 Land use land cover (LULC) data are essential for understanding and managing environmental processes and socioeconomic activities. This data informs decision-making in many domains, such as envir...

We consider the task of spatio-temporal landcover monitoring and formulate it as follows: Given a time sequence of multispectral satellite images of an area of interest (AOI), we want to predict a corresponding sequence of semantic segmentations with segment labels representing landcover types. We propose to combine asymmetric UNets (achieving super-resolution segmentation) with Markov chain models to account for both spatial and temporal dependencies. Such models cannot be trained in a supervised manner, as obtaining dense spatio-temporal annotations for satellite image time sequences is infeasible. We therefore focus on the challenge of their semi-supervised training. The proposed approach is evaluated on the task of forest monitoring in a national park in the Czech Republic, which suffers a severe forest dieback due to droughts and bark beetle outbreaks. We achieve 83% (90%) prediction accuracy in this challenging task.

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.

Understanding of the formation and evolution of supraglacial lakes in high mountain regions is crucial for accurately assessing their impact on glacier behaviour, hydrology, and potential hazards such as outburst floods. This article examines the annual spatio-temporal evolution of supraglacial lakes on the Belvedere Glacier between 2000 and 2023. Very high-resolution aerial photography and high-resolution satellite imagery were used to identify supraglacial lakes as small as 37 m2 and narrow bands of ice-marginal lakes. The mapping revealed that the well-known Lake Effimero is stable in its position but unstable in size, with variations from 428 m2 to 99.7 × 103 m2. These changes are potentially due to snowmelt or glacier dynamics. In 2002, the area of Effimero was at its largest extent observed during the study period. The first appearance of the Lake Effimero was revelated by the Landsat imagery on 27 May 2001, which differed from the findings of other studies. New lakes were observed to form in a manner independent of Effimero formation, exhibiting a consistent annual occurrence with nearly linear area growth up to 9.7 × 103 m2 in 2023. The formation of the lakes is shown to be influenced by their morphological characteristics.

Glacier retreat is a key indicator of climate change, with significant implications for geomorphological hazards and ecosystem stability. This article focuses on the surface evolution of the Belvedere Glacier from 1951 to 2023. Using high-resolution orthophotos and manual mapping, we tracked changes in the glacier’s area and shape over time. The results show three significant phases of change: the separation of the Nordend Glacier from the Belvedere Glacier (1951–1991), the partial separation of the central accumulation basin from the debris-covered tongue (2006–2015), and the separation of the Locce Nord Glacier (2018–2021). These changes, combined with a surge event from 1999 to 2002, have significantly altered the glacier’s dynamics and accelerated its retreat. Manual mapping was accurate in areas with scarce debris cover but faced challenges in debris-covered areas due to limited image resolution, snow cover, and debris characteristics. Despite these difficulties, we observed that the glacier remained stable until the late 1990s, when it began a rapid retreat. This recent retreat is consistent with rates observed in the early 20th century. The study highlights the importance of surface mapping to quantify the areal loss and to understand broader changes in glacier structure and mass flow that drive its retreat. Our results provide key data for future studies and highlight the need for continued monitoring of Alpine glaciers in the context of accelerating climate change.

The Belvedere glacier is an intensively studied glacier in the Italian Alps on the east face of the Monte Rosa, which is currently undergoing a fast deglaciation connected to various slope failures and Glacial Lake Outburst Floods. Measurements of the terminus position have been carried out since the 1920s. Since 2000, more attention has been paid to this area due to the occurrence of large mass movements and a surge-type event. In this review, research articles and various reports dealing mainly with glacier dynamics, rock and ice avalanches, Glacial Lake Outburst Floods, and other hazardous processes were considered. Aerial photogrammetry, Unmanned Aerial Vehicles, satellite stereo-processing and several terrestrial approaches (laser scanning, geophysics, measurements of near-surface heat flow, ablation stakes and camera-lapse) provided a base for quantifying the ongoing processes. Despite efforts based on the comparison of Digital Elevation Models, this review shows that the evolution of the Belvedere glacier in terms of ice volume is still partially unknown due to the low temporal frequency of aerial surveys, technical limitations of the Unmanned Aerial Vehicles used, and the fact that most studies focus only on the lower part of the glacier. The hazardous supraglacial Effimero lake that appeared during the surge-type event has been well documented, and interventions to mitigate potential risks were put in place, but the trigger of the event and the evolution of the lake basin have not yet been clarified. Mass wasting and outburst floods are mainly documented in the grey literature. The degradation of permafrost was suggested to be the driver of rock and ice avalanches, including one of the largest ice avalanches in the Alps, which occurred in 2005. In summary, the Belvedere Glacier and the surrounding rock walls have experienced repeated slope failures, an incident of surge and several outburst floods. Despite regular monitoring, a clear picture of its behavior due to the changing climate is still unknown. This review is intended to pave the way for further integrative studies.