Completed projects

Glacier retreat is one of the most visible signs of ongoing climate change, and repeated glacier photography is possibly one of the most immediate way to visualize and communicate the alarming rate of this change. This project sets out to guarantee long-term accessibility to a unique record of glacier photographs that have been collected over the years. Starting from a pool of over 50,000 images available at the project’s host institution, the aim is to integrate these historic documents in the Image Archive of the ETH Library. The images will be indexed, digitised and georeferenced with the help of volunteers, and made accessible through ETH’s E-Pics platform. This will ensure long-term accessibility to an unique set of observations, thus creating added value for both researchers and the general public. For an already-processed image of Grosser Aletschgletscher in 1927, visit external pagesmapshot.heig-vd.ch/visit/98525call_made

The worldwide retreat of glaciers caused by ongoing climate change is source of an ever increasing number of concerns: Glacier wastage significantly affects sea-level change, water availability in mountain regions, and glacier-related hazards. Obtaining global-scale information about glacier evolution is thus of utmost importance, and this is commonly done by combining remote-sensing observations with model simulations. To date, however, models operating at the global scale are strongly simplified, and fail to account for some fundamental glaciological processes.

This project sets out to revise both the basis upon which global glacier changes estimates are computed, and the way these estimates can be interpreted. This will be done by harnessing recent advances in obtaining globally-complete glaciological data, and by including some hitherto unaccounted processes into global glacier projections.

The initiative is designed along three work packages. The first is dedicated to model development, and will improve the way processes such as ice dynamics or glacier mass balance are included in global glacier models. The second package will quantify glacier changes in the recent past by developing and applying procedures extracting glacier-related information from achieved satellite imagery. These data will be pivotal for both model calibration and validation. The third package will combine the above advances with the newest generation of climate projections to produce improved predictions of global glacier changes. The analysis of the results will focus on regional-scale differences, and on scenarios that have both economic and policy relevance.

The project leverages recent advances in a number of scientific disciplines and bridges the gap between local- and global-scale assessments that are necessary for the design of strategies for climate change mitigation and adaptation.

Glaciers are important elements of the Swiss landscape and knowledge about their changes is of value in a wide range of contexts. The direct monitoring of glaciers in the field, however, is demanding, both in terms of time and manpower. This causes glacier-related information to be intermittent and to have sparse spatial coverage. In particular, reliable information is missing during summer, when the public interest is highest.

This project aims at rectifying this by working towards near real-time glacier monitoring in Switzerland. This will be achieved by combining (i) a set of low-cost sensors that provide glacier-change information on a daily basis with (ii) meteorological data provided by the Federal Office for Meteorology and Climatology (MeteoSwiss) and (iii) numerical glacier models. Whilst the sensors will provide the necessary ground-truth information, the numerical modelling and the meteorological data will allow for the information to be extended in its spatial coverage.

The integration of complementary information sources – notably further field-based data from the Glacier Monitoring in Switzerland (GLAMOS) programme, glacier elevation changes derived from multitemporal digital elevation models of the Federal Office of Topography (swisstopo), as well as satellite data from the European Space Agency’s Copernicus programme – will help to deliver up-to-date glacier information at any point in time.

The project is an extension of the activities pursued within "CRAMPON", and is made possible throuh the external pageGlobal Climate Observing System (GCOS) Switzerlandcall_made.

Switzerland stands out as one of the countries with the longest records of glacier changes, and long-term observations are crucial in order to understand the impact of glacier retreat on water resources or hydropower production. Despite this importance, only a few dozen of glaciers have observations extending further back than three decades

The aim of this project is to process a unique archive of several thousand historical terrestrial images in order to document glacier area, length and volume changes at a centennial scale. The photographs were acquired in the 1920s until 1940s by the Federal Office of Topography (swisstopo) to generate historical maps. A 3D-representation of the largest Swiss glaciers will be reconstructed from stereoscopic image pairs and using modern photogrammetric techniques. These will then be compared to modern topography and yield an estimate of the total ice volume change.

The project is performed in collaboration with the external pageInstitute of Territorial Engineering (INSIT)call_made and external pageswisstopocall_made, and it is made possible through the external pageGlobal Climate Observing System (GCOS) Switzerlandcall_made.

Due to ongoing climate change glaciers, mountain permafrost and periglacial features are undergoing rapid changes. When it comes to the water contribution of these elements, clean-ice glaciers have been studied relatively extensively whilst the significance of rock glaciers is less well understood. Rock glaciers are stratified rock-ice features and can be several millennia old. Their characteristic coarse blocky surface layer provides some insulation from atmospheric warming and rock glaciers are thought to be less sensitive to changes in climate. The aim of this project is to estimate the evolution of the thermal regime and potential melt of rock glaciers under future climate scenarios, thus assessing their future potential as water contributors.

The rock glacier’s coarse blocky surface introduces some challenges when modelling their thermal regime. In particular, ventilation effects – that are effects due to either natural convection caused by differential heating at the top and bottom of cavities or to forced convection induced by wind – need to be accounted for. To do so, this project employs the numerical models external pageSNOWPACKcall_made and the in-house Glacier Runoff Evolution Model – Permafrost (GERM-P). The physics-based model SNOWPACK will be used to gain a deeper understanding of the relevant processes, whilst the conceptual, parametric model GERM-P will be used for applications at the catchment scale.

By using the two models, the project will allow to (a) further improve GERM-P, (b) provide long-term simulations for selected rock glacier sites in the Swiss Alps, and (c) quantify the potential runoff contribution from rock glaciers under future climate scenarios.

This project is an integral part of WSL’s external pageClimate Change Impacts oncall_made external pageAlpine Mass Movements (CCAMM)call_made initiative and builds upon field data collected in the frame of the Swiss Permafrost Monitoring Network (PERMOS).

Mass movements, such as rockfalls, debris flows (a mixture of water, sediments and boulders), and ice avalanches, in steep mountain torrents have a highly destructive potential. As alternative to classical monitoring and early warning instrumentation, seismology - the study of ground motions induced by a force within the earth - allows monitoring of mass-movement-induced ground shaking at safe distance to rapidly detect and locate a flow front. The aim of this project is to better understand the dynamics and triggering mechanisms of mass movements in a changing climate.

Traditionally, seismology is associated with earthquakes, where ruptures in the earth crust release elastic energy in the form of seismic waves which then propagate through the earth. In recent years, a new field called „Environmental Seismology“ has evolved, which focuses on seismic signals generated by environmental forces at the earth surface. Advances in instrumentation size and portability allow only lately the deployment of seismometers in remote terrain. Utilizing the knowledge accumulated from decades of research in earthquake seismology, processes of mass movements can be monitored. The project mostly focuses on the Illgraben, a steep mountain catchment in the Valais, which is one of the most active mass wasting sites in Switzerland producing several debris flows per year. To study these, data from recent years as well as data from new deployments in sping/summer 2018 are used. In addition, other study sites are investigated for information on the influence of snow and ice on mass movement processes.

This project will perform a comprehensive 3D characterization of the ice mass using ground-penetrating-radar (GPR) and seismic techniques. The geophysical results will be integrated in ongoing activities geared towards a better understanding of the hydrology of glaciers.

Besides commonly used surface measurements, crosshole surveys using multiple boreholes will be performed. The data will not only be analyzed with state-of-the-art 3D travel time and amplitude tomography, but also with full waveform inversion techniques. This will allow for the fulll the information content of the geophysical data to be exploited. Particular emphasis will be put on analysing the anisotropy of the electrical and elastic ice properties, which will offer key information on the ice structure and thus preferential water flow paths within the ice itself. The geophysical results will be calibrated with laboratory investigations of ice cores extracted at the test sites. For a detailed characterization of the glacier bed properties, joint inversions of GPR and seismic data will be performed. Attribute analyses will allow delineating the bedrock topography, determining the existence of subglacial drainage channels, and identifying the presence of sedimentary layers.  

Glacier lake outburst floods (GLOFs) are a natural hazard characteristic of high alpine environments. This project sets out to take advantage of a unique situation emerging at Glacier de la Plaine Morte, Switzerland: With the aim of mitigating an annually-occurring GLOF, the local authorities have decided to construct an englacial channel through which the lake will be drained artificially. The project will perform dedicated measurements during the time that water flows through the artificial channel. Exploiting the unique fact that the initial channel location and geometry are known, the measurements will allow for testing both long-standing theories of englacial water flow and more recently proposed monitoring strategies based on seismics.

Whilst detailed inventories exist for the Swiss glacier area, only rough estimates are available for the ice volume. Until recently, direct measurements of ice thickness were limited to a few selected glaciers. Over the last 5 years, more than 1500 km of helicopter ground penetrating radar (GPR) profiles have been recorded, supported by the Swiss Geophysical Commission (SGPK) and the external pageSwiss Competence Center for Energy Research - Supply of Electricity (SCCER-SoE)call_made. The combinations of these data with recently-developed approaches for estimating the basal topography, will allow to obtain new, high-precision estimates of the ice thickness distribution of all glaciers in Switzerland.

This project will focus on the choice of a optimal GPR system, an improved processing scheme, the acquisition of measurements and the evaluation of the total ice volume. Helicopter-borne GPR allows the efficient acquisition of measurements. Different radar systems have been tested in the frequency range of 15 to 70 MHz. Measurements with the same GPR antennas on ground revealed a wealth of useful information on both the glacier bed topography and the technical nature of the system. Based on these results, a new towed radar system based on two orthogonal antenna pairs was constructed and successfully tested. The project will provide better estimates for the total amount of ice stored in the Swiss Alps at present.

Long-term glacier monitoring in Switzerland has resulted in some of the longest and most complete data series at the global scale. The direct observations of mass balance date back until the late 19th century and, at some sites, have been continued until today. Data acquired in the frame of GLAMOS are stored in a database and documented metadata are available for the more recent measurements. For observations performed before about the year 2000, in contrast, it is often difficult to reconstruct complete sets of metadata. However, accurate metadata are highly important for homogenisation of the in-situ measurements and for tracing the origin of the observations. Furthermore, metadata are indispensable for the re-analysis of the long-term series, including an assessment of their uncertainty.

The present project sets out to significantly advance the documentation of long-term glacier data within Swiss glacier monitoring activities. First, we will target the rescue and homogeneous storage of yet scattered data of seasonal/annual point mass balance (both in printed and digital form). Second, a better documentation of metadata is envisaged allowing full traceability – wherever possible – of the applied measurement methods and the involved uncertainties. Third, we aim at completely re-analysing long-term series of glacier-wide mass balance in order to deliver consistent data sets for further studies. All rescued, documented and homogenized glacier data will be stored and made available for scientific and public needs.

The project is an extension of the activities pursued within external pageGlacier Monitoring in Switzerland (GLAMOS)call_made, and is made possible through the external pageGlobal Climate Observing System (GCOS)call_made Switzerland.

Early warning systems of mass movements often use different instrumentation to detect events. Since the events occur within short time windows, however, observations with static instruments are difficult. This project aims at setting up an interactive network of autonomously communicating instruments to capture processes happening during and directly after alpine mass movements, and debris flows in particular. The investigations will target the Illgraben catchment, Valais. The project's key innovation is to trigger an autonomous Unmanned Aerial Vehicle (UAV) through seismic detections. The UAV will fly along the torrent, and collect imagery of both the flow front and the sediment source areas. Close-range photogrammetry techniques will be used to extract terrain movement. The collected data will allow for insights into debris flow dynamics, provide input for numerical models, and inform risk assessment and mitigation measures.

In this project we analyze new landscapes which are emerging though glacier retreat, and identify locations which may be suitable for potential new water storages and hydropower production once glaciers have retreated. This involves modelling the physical hydropower potential but also taking into account environmental, social and economic factors to assess the feasibility of each location.

The determination of the volume of a glacier is one of the most challenging topics in glaciology. Ice thickness distribution is a necessary input to various glaciological applications ranging from ice flow models, the assessment of changes in local to regional hydrology, to global projections of sea-level rise from glacier melt. Recently, several methods have been developed to derive glacier bedrock from surface topography based on the principles of ice flow dynamics.

In this project we developed a new ice thickness model which uses Bayesian-statistics methods to produce maps of ice thickness from available data, such as surface elevation, ice flow speed and ice thickness measurements. The ice flow speed data is from the main project of Glaciers_CCI (University of Zurich). We applied the model to more that 30'000 glaciers in five regions of the world: Arctic Canada North and South, Svalbard, European Alps and Pyrenees, and Karakoram. Our results show that our method is competitive with existing methods and improves on them by also calculating maps of the error of the estimated ice thickness.

The Little Ice Age in Europe (between about 1350 and 1850) marked the largest glacier extent over the entire Holocene period. However, the causes of the substantial glacier advances in the mid-​19th century and the rapid retreat following this phase are yet unclear. The so-​called “paradox of the Little Ice Age” refers to the long-​standing problem why glaciers in the Alps experienced rapid growth around 1850 and subsequent decline despite air temperatures remaining at a low level until 1920.

In this project, we intended to further develop regional models for glacier surface mass balance and ice flow dynamics at the scale of the entire Swiss Alps in order to shed light on the paradox of the Little Ice Age. We included the important processes of solar radiation forcing and the feedback of surface impurity concentration on snow and ice albedo into a mass balance model with little input data demand (temperature, precipitation). Changes in ice thickness and ice flow speed, and ultimately glacier advance and retreat, have been computed with a three-​dimensional model for ice flow dynamics operating at the regional scale. Both models have been coupled and run over the entire period with instrumental data (1760 to present). By performing experiments with various assumptions on the forcing variables using the combined mass-​balance ice-​flow model, we attempted to reproduce observed maximum glacier extent and measured length changes. This will finally allowed us to attribute glacier response to a combination of different climatic forcing mechanisms – temperature, precipitation, solar radiation, surface impurities/albedo.

Understanding the drivers of the exceptionally fast glacier change around the Little Ice Age maximum is of eminent importance for an improved understanding of glacier sensitivity in the past and at present, as well as and for future glacier projections. In fact, the clear documentation of glacier advance and retreat around 1850 via historical and geomorphological evidence provides the exciting opportunity to study the involved processes and to resolve their relative importance.

With the federal “Energy Strategy 2050” hydropower production is supposed to increase to partly compensate for the planned nuclear power pullout. Besides upgrades of existing hydropower schemes, there is a potential from new developments in newly formed landscapes in front or just beyond the outer limits of glaciers (periglacial zones). The immediate proximity to the glacial environment, however, will pose challenges in terms of construction, operation and maintenance. In particular, the high sediment yields from glacierized and deglacierizing areas are of concern.

The goal of the project was to assess the sediment yields in glacierized catchments of the Swiss Alps. In particular, we provided answers to the following questions: (1) What is the present sediment yield in the glacierized catchments of the Swiss Alps, and what was its temporal evolution over the last decades? (2) What are the causes of the recently observed increase in sediment discharge? (3) What is causing different sediment discharges for different catchments? (4) How will the sediment discharge evolve in the coming decades?

Erosion rates and sediment flux have directly been measured for a set of selected catchments, and the data have been used to develop a glacier-hydrology model which takes erosion and sediment transport into account. The sensitivity of sediment yields to changes in glacier extent and climate forcing has been explored. The developed model is able to capture the temporal evolution of sediment yields within a basin, and provided a framework to understand differences in sediment yields from different catchments.

Subglacial hydrology plays a key role in many glaciological processes, including ice dynamics via the modulation of basal sliding. Owing to the lack of an overarching theory, however, a variety of model approximations exist to represent the subglacial drainage system. The Subglacial Hydrology Model Intercomparison Project (SHMIP) puts together a set of synthetic experiments to compare existing and future models.

The study presents the results from 13 participating models with a focus on effective pressure (ice overburden pressure minus water pressure) and discharge. For many applications (e.g. steady states and annual variations, low input scenarios) a simple model, such as an inefficient-system-only model, a flowline or lumped model, or a porous-layer model provides results comparable to those of more complex models.

However, when studying short term (e.g. diurnal) variations of the water pressure, the use of a two-dimensional model incorporating physical representations of both efficient and inefficient drainage systems yields results that are significantly different from those of simpler models and should be preferentially applied. The results also emphasise the role of water storage in the response of water pressure to transient recharge. Finally, we find that the localisation of moulins has a limited impact except in regions of sparse moulin density.