Abstract. As Alpine glaciers become snow-free in summer, more dark, bare ice is exposed, decreasing local albedo and increasing surface melting. To include this feedback mechanism in models of future deglaciation, it is important to understand the processes governing broadband and spectral albedo at a local scale. However, few in situ reflectance data have been measured in the ablation zones of mountain glaciers. As a contribution to this knowledge gap, we present spectral reflectance data (hemispherical–conical–reflectance factor) from 325 to 1075 nm collected along several profile lines in the ablation zone of Jamtalferner, Austria. Measurements were timed to closely coincide with a Sentinel-2 and Landsat 8 overpass and are compared to the respective ground reflectance (bottom-of-atmosphere) products. The brightest spectra have a maximum reflectance of up to 0.7 and consist of clean, dry ice. In contrast, reflectance does not exceed 0.2 for dark spectra where liquid water and/or fine-grained debris are present. Spectra can roughly be grouped into dry ice, wet ice, and dirt or rocks, although gradations between these groups occur. Neither satellite captures the full range of in situ reflectance values. The difference between ground and satellite data is not uniform across satellite bands, between Landsat and Sentinel, and to some extent between ice surface types (underestimation of reflectance for bright surfaces, overestimation for dark surfaces). We highlight the need for further, systematic measurements of in situ spectral reflectance properties, their variability in time and space, and in-depth analysis of time-synchronous satellite data.

Abstract. As Alpine glaciers recede, they are quickly becoming snow free in summer and, accordingly, spatial and temporal variations in ice albedo increasingly affect the melt regime. To accurately model future developments, such as deglaciation patterns, it is important to understand the processes governing broadband and spectral albedo at a local scale. However, little in situ data of ice albedo exits. As a contribution to this knowledge gap, we present spectral reflectance data from 325 to 1075 nm collected along several profile lines in the ablation zone of Jamtalferner, Austria. Measurements were timed to closely coincide with a Sentinel 2 and Landsat 8 overpass and are compared to the respective ground reflectance products. The brightest spectra have a maximum reflectance of up to 0.7 and consist of clean, dry ice. In contrast, reflectance does not exceed 0.2 at dark spectra where liquid water and/or fine grained debris are present. Spectra can roughly be grouped into dry ice, wet ice, and dirt/rocks, although transitions between types are fluid. Neither satellite captures the full range of in situ reflectance values. The difference between ground and satellite data is not uniform across satellite bands, between Landsat and Sentinel, and to some extent between ice surface types (underestimation of reflectance for bright surfaces, overestimation for dark surfaces). We wish to highlight the need for further, systematic measurements of in situ spectral albedo, its variability in time and space, and in- depth analysis of time-synchronous satellite data.

<p>Glaciers are retreating at an historically unprecedented pace. Climate-determined processes are changing markedly. As a result, proglacial areas are expanding. Paraglacial dynamics are expected to further increase in significance, controlling sediment supply and landscape change in mid- to high latitudes for the next few hundred years. Paraglacial adjustment in proglacial areas has not been fully explored to date and there is an urgent need to monitor and understand these systems in more detail.</p><p>We present first insights into a planned project called glacier2go aiming to investigate changes in the paraglacial system in the highly variable and sensitive areas determined by rapid glacier retreat at two Austrian glaciers. The project aims at the development of a new holistic monitoring system, where remote sensing and field work data are combined and integrated to achieve a deeper understanding of the different stages of evolution of the paraglacial system, and to detect changes through classification approaches. The project glacier2go will fill a research gap by developing an automatic land cover classification model with very high spatial and temporal resolution for monitoring geomorphic changes. glacier2go will capture surface changes through contrasting geomorphic-classification maps.</p><p>The proposed survey will be conducted on selected glacier forefields in the Austrian Alps with Jamtalferner (Tyrol, Silvretta) and Pasterze (Carinthia, Glockner range) as the main study sites. glacier2go will be executed as a dissertation project hosted at the Interdisciplinary Institute of Mountain Research (IGF) in Innsbruck, Austria. International cooperation partners in the field of geomorphology, photogrammetry and geoinformation are on board to realize this project.</p><p>At the current stage first data comparisons are shown, emphasising the needed research on the interlinkage of geomorphology and the methodical development of new monitoring systems. Setting these first insights into the framework of paraglacial geomorphology leads to the emergence of new research questions. The associated challenges and first approaches for their solution are presented at the conference.</p>

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