A5040705908- Cryospheric studies and observations
- Winter Sports Injuries and Performance
- Landslides and related hazards
- Climate change and permafrost
- Geology and Paleoclimatology Research
- Arctic and Antarctic ice dynamics
- Hydrology and Watershed Management Studies
- Methane Hydrates and Related Phenomena
- Polar Research and Ecology
- Icing and De-icing Technologies
- Robotic Mechanisms and Dynamics
- Adventure Sports and Sensation Seeking
- Geological Modeling and Analysis
- Hydrology and Sediment Transport Processes
- Geological formations and processes
- Groundwater flow and contamination studies
- Soil erosion and sediment transport
- stochastic dynamics and bifurcation
- Geotechnical Engineering and Analysis
- Smart Materials for Construction
- Soil and Unsaturated Flow
- Meteorological Phenomena and Simulations
- Advanced Wireless Communication Techniques
- Karst Systems and Hydrogeology
- Algorithms and Data Compression
ETH Zurich
2016-2025
Swiss Federal Institute for Forest, Snow and Landscape Research
2019-2025
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering
2020-2024
University of Zurich
2014-2016
Simon Fraser University
2012-2013
University of Bristol
2013
At Bristol
2009-2012
University of Kaiserslautern
2005
[1] We present a two-dimensional Glacier Drainage System model (GlaDS) that couples distributed and channelized subglacial water flow. Distributed flow occurs through linked cavities are represented as continuous sheet of variable thickness. Channelized Röthlisberger channels can form on any the edges prescribed, unstructured network potential channels. Water storage is accounted for in an englacial aquifer moulins, which also act point sources to system. Solutions presented synthetic...
Abstract Gornersee, Switzerland, is an ice-marginal lake, which drains almost every year, subglacially, within a few days. We present analysis of the lake outburst events between 1950 and 2005, as well results detailed field investigations related to drainage in 2004 2005. The latter include measurements geometry, water pressure nearby boreholes glacier surface motion. A distributed temperature-index melt model coupled linear-reservoir runoff used calculate hourly discharge from catchment...
ABSTRACT Subglacial hydrology plays a key role in many glaciological processes, including ice dynamics via the modulation of basal sliding. Owing to lack an overarching theory, however, variety model approximations exist represent subglacial drainage system. The Hydrology Model Intercomparison Project (SHMIP) provides set synthetic experiments compare existing and future models. We present results from 13 participating models with focus on effective pressure discharge. For applications (e.g....
Knowing the ice thickness distribution of a glacier is fundamental importance for number applications, ranging from planning glaciological fieldwork to assessments future sea-level change. Across spatial scales, however, this knowledge limited by paucity and discrete character available observations. To obtain spatially coherent thickness, interpolation or numerical models have be used. Whilst first phase Ice Thickness Models Intercomparison eXperiment (ITMIX) focused on approaches that...
Abstract We present a continuum model for melt water drainage through spatially distributed system of connected subglacial cavities, and consider in this context the complications introduced when effective pressure or drops to zero. Instead unphysically allowing become negative, we formation partially vapour- air-filled space between ice bed. Likewise, instead sustained negative pressures, allow separate from bed at zero pressure. The resulting is free boundary problem which an elliptic...
Abstract We present a new model of subglacial drainage incorporating flow in network channels and porous sheet, with water exchange between the two determined by pressure gradients. The sheet represents average effect many linked cavities, whilst emerge from individual cavities that enlarge due to dissipation-induced melting. distinguishes cases when drops zero, which case it allows for space be only partially filled (free surface flow), reaches ice overburden pressure, uplift whatever...
ABSTRACT Over recent decades, Greenland ice sheet surface melt has shown an increase both in intensity and spatial extent. Part of this water probably reaches the bed can enhance glacier speed, advecting a larger volume into ablation area. In context warming climate, mechanism could contribute to future rate thinning retreat land-terminating glaciers Greenland. These changes flow conditions will turn influence crevassing thus ability reach at higher elevations. Here, using coupled basal...
Sediment discharge from glaciers impacts downstream aquatic habitats, hydropower operations, and river infrastructure. Since of subglacial sediment will evolve in response to glacier retreat, estimating future dynamics is great relevance. To develop tools methods better constrain the responsible processes, we present a till model that accounts for limited access coupled hydrology describe evolution layer over glacier's longitudinal profile one dimension. Synthetic simulations examining...
Because the majority of sediment originates subglacially, as opposed to proglacially, focus must be given subglacial discharge. The latter, however is poorly constrained. We present a transport time-series from two glacierized catchments (Gornergletscher and Aletschgletscher) in Swiss Alps, based on hourly suspended data bedload estimates. This dataset used identify interannual regional variability quantify relationship between water Analysis suggests that access exerts substantial control...
The link between subglacial hydrology and basal sliding has prompted work on models with water pressure drainage capacity as prognostic variables. We find that the Glacier Drainage System model, which belongs to a commonly used family of include both channelized distributed components, underpredicts winter when compared borehole observations from western Greenland given wide range plausible parameter values inputs. This problem, though previously noted by other modelers, not been addressed....
Abstract Accurate estimations of ice thickness and volume are indispensable for flow modelling, hydrological forecasts sea-level rise projections. We present a new estimation model based on mass-conserving forward Bayesian inversion scheme. The calculates flux in an elevation-band flow-line model, translates this into surface speed using shallow formulation. Both then extrapolated to the map plane. assimilates observations scheme implemented with Markov chain Monte Carlo method, which...
Abstract Large units of disrupted radiostratigraphy (UDR) are visible in many radio‐echo sounding data sets from the Greenland Ice Sheet. This study investigates whether supercooling freeze‐on rates at bed can cause observed UDR. We use a subglacial hydrology model to calculate both freezing and melting base ice sheet distributed within basal channels. find that while is phenomenon occurs areas sheet, there no discernible correlation with occurrence The so low it would require tens thousands...
Recovery Ice Stream has a substantial number of active subglacial lakes that are observed, with satellite altimetry, to grow and drain over multiple years. These store release water could be important for controlling the velocity ice stream. We apply hydrology model analyze lake growth drainage characteristics together simultaneous development stream hydrological network. Our outputs produce good match between modeled location those identified using altimetry many lakes. The system...
Abstract. The growth and drainage of active subglacial lakes in Antarctica has previously been inferred from analysis ice surface altimetry data. We use a hydrology model applied to synthetic Antarctic stream examine internal controls on the filling lakes. Our outputs suggest that highly constricted environment our idealized stream, combined with relatively high rates water flow funneled large catchment, can combine create system exhibiting slow-moving pressure waves. Over period years,...
We investigate the dynamics of Bose-Einstein condensates in a tilted one-dimensional periodic lattice within mean-field (Gross-Pitaevskii) description. Unlike linear case Bloch oscillations decay because nonlinear dephasing. Pronounced revival phenomena are observed. These analyzed detail terms simple integrable model constructed by an expansion Wannier-Stark resonance states. also briefly discuss pulsed output such systems for stronger static fields.
Abstract. The surface of Unterer Grindelwaldgletscher glacier tongue has subsided by more than 200 m over the last 150 years. lowering is not uniform but depends on thickness uneven debris cover, which led to formation a depression tongue. A lake can form in this basin, occurred for first time 2005. Such drain rapidly leading so-called outburst flood. basin been increasing size at an alarming rate and 2008, it reached volume poses significant flooding threat communities downstream, as was...
Abstract Observational data allowing the validation of jökulhlaup models are sparse. We were able to inject dye tracer directly into drainage channel a glacial lake during onset its outburst. This made it possible test an established model, not only against discharge measurements, but for first time also water flow speeds inferred from measurements. drive based on Spring–Hutter equations, with measured subglacial pressure, temperature and level. The model is fitted using initial size,...
Abstract In the spring of 1818, ice avalanches from Giétro Glacier created an dam, which in turn formed a glacial lake Drance Valley (Canton Valais, Switzerland). Today, its maximum volume is estimated to have been 25×10 6 m 3 . Cantonal authorities commissioned engineer named Ignaz Venetz mitigate risk dam's failure. He supervised construction tunnel through large water was drained as rose (9×10 according his estimates and 11×10 our model). After 2.5 days slow drainage, dam failed on 16...
Abstract Our understanding of the subglacial drainage system has improved markedly over last decades due to field observations and numerical modelling. However, integrating data into increasingly complex models remain challenging. Here we infer two-dimensional channel networks hydraulic parameters for Gorner Glacier, Switzerland, based on available at five specific times (snapshots) across melt season 2005. The dataset is one most complete available, including borehole water pressure, tracer...
A better knowledge of sediment transport is needed to understand the distribution sediments beneath ice, and signals cryosphere change that may be detected in glacial deposited offshore. We present here an updated graph-analysis approach enable further exploration sedimentary consequences hydrological allows for a quantitative estimate water fluxes subglacial environment, associated basal till evolution properties, impacting on glacier sliding hydrogeology processes. The analysis based...
Basal sliding and other processes affecting ice flow are challenging to constrain due limited direct observations. Inversion methods, which typically fit an model observed surface velocities, enable the reconstruction of basal properties from readily available data. We present a numerical inversion framework for reconstructing glacier coefficient, applied both synthetic real-world alpine scenarios. The employs automatic differentiation generate adjoint code runs in parallel on graphics...
The term "water pocket" is often used as an umbrella to describe the unknown origin of glacial outburst floods. There currently no consensus on its definition and formation rupture mechanisms water pockets remain poorly understood. Here, we define a pocket englacial or subglacial water-filled cavity with volume larger than 1000 m3. Glacier floods originating from are called (WPOFs). WPOFs in contrast glacier lake (GLOFs), for which giving rise flood stems detectable reservoir located either...
Abstract Beneath Antarctica’s ice sheets, a little-observed network of liquid water connects vast landscapes and contributes to the motion overriding ice. When this subglacial reaches ocean cavity beneath shelves, it mixes with seawater, amplifying melt in places forming deep channels base Here we present observations from hot-water-drilled borehole documenting entering at grounding zone Kamb Ice Stream Ross Shelf. Our show that has removed approximately third thickness, yet measurements...