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Publications

Automated Detection of Glacier Surges from Sentinel-1 Surface Velocity Time Series—An Example from Svalbard

Research on surge-type glaciers, although they constitute a small percentage of all glaciers, significantly contributes to understanding glacier flow mechanisms. Recent studies have utilized remote sensing techniques to unravel these processes, highlighting the potential of combining high-performance computing and earth observation. While modeling surge events has gained popularity, there is a lack of comprehensive spatial and temporal data on surge timing. To address this, an algorithm has been developed that not only detects surge-type glaciers but also determines the onset of surges. The algorithm relies on time series analysis of glacier surface velocity using Sentinel-1 data, involving seasonal and trend decomposition and outlier detection via the General Studentized Extreme Deviate Test. Cluster analysis is then applied to identify outlier clusters associated with glacier surges. The method’s effectiveness was demonstrated in the Svalbard archipelago between 2015 and 2021, where 18 glacier surges and their timing were successfully identified.

https://www.mdpi.com/2072-4292/15/6/1545

Allgemein Publications

AMD-HookNet for Glacier Front Segmentation

This article discusses the importance of tracking changes in glacier calving front positions as a means of assessing glacier status. Remote sensing imagery is a valuable tool for this purpose, but manual monitoring for all global calving glaciers is impractical due to time constraints. The article introduces a novel framework called AMD-HookNet, designed for the segmentation of glacier calving fronts in synthetic aperture radar (SAR) images. AMD-HookNet enhances feature representation by leveraging an attention mechanism and interactions between low-resolution and high-resolution inputs. The experiments conducted on a benchmark dataset demonstrate that AMD-HookNet outperforms the current state of the art by achieving a mean distance error of 438 meters to the ground truth, confirming its effectiveness.

https://ieeexplore.ieee.org/document/10044700?source=authoralert

Publications

A Tutorial on the Sequential Sampling Impulse Radar Concept and Selected Applications

The concept of the sequential sampling is well known and still widely used in industrial automation radar applications due to its hardware simplicity, low cost and low power consumption. However, there is only a limited amount of publications that describe this concept and its variants in detail. This tutorial introduces the typical sequential sampling impulse radar concept step by step and presents several key characteristics, such as correlation properties and SNR considerations. In addition to the system theory, selected applications are presented to illustrate the attractiveness and elegance, but also the limits of this radar concept. The shown applications range from those in industrial automation to radar concepts in the areas of automotive radar, security scanners, biomedical radar systems and ground penetrating radar. The latter application is among others including the analysis of glaciers, e.g. to determine the ice thickness and stratification in order to provide a better understanding of the glacier and its behavior in a changing climate.

The corresponding paper can be found here:

A Tutorial on the Sequential Sampling Impulse Radar Concept and Selected Applications

Event

Annual Retreat at Josefstal in November 2022

The first annual Retreat within the IDP M3OCCA took place at “Studienzentrum Josefstal” in early November 2022.

During the workshop, all Ph.D. students provided an overview of their individual PhD projects with subsequent discussions.

Additionally, further steps within the IDP M3OOCA program were discussed and defined.

Event

Kick-Off workshop in Erlangen June 2022

Right to the beginning of the IDP M3OCCA, we organized a “kick-off” workshop at FAU Erlangen in June 2022.

The workshop was the first gathering of all IDP M3OCCA Ph.D. students, including affiliated Ph.D. students. Many subproject supervisors were also around, so the workshop provided the fundament for a fruitful exchange and collaboration between all different institutions involved in the IDP M3OCCA.

 

SP3 SPs

SP3.1: Targetting snow drift and refreezing in glacier mass budgets with machine learning

Subproject 3.1

Targetting snow drift and refreezing in glacier mass budgets with machine learning

Glacier surface mass balance (SMB) modelling has traditionally focused on improving the determination of surface energy balance conditions. However, water routing in the firn including refreezing, as well as the complex patterns of surface accumulation caused by snow drift, are poorly, or not at all, represented in most SMB models. Studies in the literature have often noted the uncertainties due to neglecting such mechanisms. This sub-project aims to improve the model representation of (i) the internal water budget and (ii) the snow drift contribution to the SMB using deep learning.
This aim links ideally with ongoing snowdrift measurements on Hintereisferner in the frame of a running joint project between FAU and the University of Innsbruck (http://schism-project.info/). It furthermore links very well with our strong background in SMB modelling and developing process-based model parameterizations. We hypothesize, however, that the accuracy of such parameterizations can be increased drastically by including machine learning algorithms and new measurements on snow drift dynamics.

In this subproject, we will explore the associated added value by sensitivity simulations and analyses of the resultant mass and energy balance components. An improved knowledge of the mechanisms in question is also important for the precise estimation of sea level contributions from glaciers measured from altimetry and DEM differencing (SP2.2 and 2.3), since the measured elevation changes have to be converted to mass using a certain density assumption. The SP also links to SP1.2 and SP1.3 where internal structures of the snow and firn cover are mapped.

For specific information on the sub-project please contact: Prof. Dr. Thomas Mölg, Institut für Geographie, Wetterkreuz 15, 91058 Erlangen, T: 09131-85-22633, thomas.moelg@fau.de, https://www.geographie.nat.fau.de/

Co-PIs: L. Nicholson, R. Prinz (Univ. Innsbruck), R. Hock (Univ. Oslo)


Get to know our project affiliated PhD students

Manuel Saigger

manuel.saigger@fau.de

Want to learn more about Manuel’s research? Click here to access a short video!
(the webcam video is from www.foto-webcam.eu)

My name is Manuel Saigger and within the IDP MOCCA I will be working on the influence of snow drift and internal refreezing on the glacier mass balance. Before I started working in Erlangen,  I studied atmospheric sciences at the University Innsbruck. There I mainly focused on weather forecasting and weather simulations in alpine terrain and got really fascinated by the complex nature of flow fields in the surrounding of mountains. These complex wind patterns can in return lead to very complex patterns in snow accumulation, for example by redistribution of the snow.

Here my project comes into play. Because despite possibly being very important, this redistribution is not reflected in most glacier mass balance models, which on the one hand creates uncertainty in these models, but on the other hand gives us the opportunity to work on this problem and learn more about these fascinating processes.

SP2 SPs

SP2.1: Glacier outlines from optical and SAR imagery by deep learning

Subproject 2.1

Glacier outlines from optical and SAR imagery by deep learning

Glacier extent is an ECV and various international attempts exist to harmonize a global glacier inventory data set with outlines if possible from multiple data sources (GLIMS, IASC Randolph Glacier Inventory, RGI).
However, to date no real operational large-scale repeat mapping capabilities exist. Glacier outlines are required at different time intervals e.g. with matching observational intervals for specific mass balance computations out of remote sensing measurements (e.g. for comparison with in-situ observations or on regional scale) or to validate ice dynamic modelling. In particular for small fast changing glaciers area updates are important since errors from area mismatch are highest.

While for calving glaciers various deep learning approaches exist outlines of land-terminating glaciers are often more difficult to delineate, in particular when the glacier tongue is debris-covered. We aim at an approach that integrates the advantages of synthetic aperture radar and optical observation capabilities and analysis techniques. The candidate is supposed to advance our existing processing setup and to develop and systematically test a new method. Within this doctoral project we aim at training a machine learning algorithm using multi-temporal SAR coherence images jointly with other data. This SP has strong thematic links to SP3.2 and 3.3 and methodological to SP 2.2.

For specific information on the sub-project please contact: Prof. Dr. Matthias Braun, Institut für Geographie, FAU, Wetterkreuz 15, 91058 Erlangen, T: +49 9131-85-22015, matthias.h.braun@fau.de, https://www.geographie.nat.fau.de/

Co-PIs: E. Bänsch (FAU Mathematics), P. Rizzoli (DLR HR), M. Zemp (Univ. ZH)


Get to know our project affiliated PhD students

Katrina Bartek

katrina.bartek@fau.de

Originally coming from Michigan in the United States, I received my bachelor’s degree in Mechanical Engineering from the University of Michigan in April 2017. After subsequently working in the aviation field for a year, I moved to Munich to pursue my master’s degree in Earth Oriented Space Science and Technology at the Technical University of Munich. This program explored the uses of remote sensing, the technology behind it, and the geophysical processes to be observed. Through this, my desire to pursue research in the cryosphere was inspired and I started research in the Institute of Geography at the Friedrich-Alexander-Universität Erlangen-Nürnberg in May 2021.

This research focused on using deep learning techniques to detect supraglacial lakes in Northeast Greenland using Sentinel-2 data. Having been accepted to the IDP M3OCCA program, I am excited to now pursue my doctoral degree with the focus on the improvement of glacier outline segmentation using various remote sensing data while using the strengths of artificial intelligence.

SP3 SPs

SP3.2: Reconciling machine learning and glacier system modelling

Subproject 3.2

Reconciling machine learning and glacier system modelling

Within this sub-project, we envisage to combine model-driven simulations of a coupled glacier system with data-driven machine learning techniques at specific benchmark sites in the Alps (e.g., Hintereisferner, Vernagtferner). A well-established ice-flow model will first be employed to produce observation-informed training and test data, which will then inform machine learning components that can replace such classical methods. The ultimate goal is to reduces computational efforts and prepare such hybrid techniques for long timescales and/or regional scales.

 

Detailed Information and position requirements of this SP are formulated in this PDF.

For specific information on the sub-project please contact:
Dr. Johannes Fürst (NGL)
Department of Geography and Geosciences, Institute of Geography
Wetterkreuz 15, 91058 Erlangen, T: 09131-85-26680, Johannes.fuerst@fau.de
Prof. Dr. Harald Köstler
Department of Computer Sciences, System Simulation
Cauerstraße 11, 91058 Erlangen, T: 09131-85-29359, harald.koestler@fau.de

Co-PIs:
I. Tabone (FAU Geography)
O. Galiardini (Univ. Grenoble)
F. Maussion (Univ. Innsbruck)


Get to know our project affiliated PhD students

Mamta KC

mamta.kc@fau.de

Want to learn more about Mamta’s research? Click here to access a short video!

After graduating with a master’s degree in Environmental and Natural Resources from Kathmandu University, Nepal, I opted for the second master’s program in Climate and Environmental Science at the FAU Institute of Geography to broaden my horizon and enhance my environmental data analysis knowledge. During my master’s program, my interest in glacier environment, climatology, and machine learning grew.

The potential of deep learning applications to understand real-world physical phenomena captured my attention. Using efficient deep learning-based models to learn physics-based glacier models is a promising field of research. Thus, I look forward to incorporating machine learning into glacier modeling during my Ph.D. in the IDP M3OCCA program. My research will focus on developing physics-based deep learning emulators that will learn to predict the glacier dynamics. The emulators will be trained using the simulated data generated from the different glacier-based physical models.

SP3 SPs

SP3.3: Mass movement assessment and modelling in recent ice-free areas

Subproject 3.3

Mass movement assessment and modelling in recent ice-free areas

The retreat of glacier ice fundamentally changes stability of the surrounding rock and debris slopes due to the massive thermal, mechanical and hydrological change initiating massive creep and rock slope failures (Haeberli et al., 2010). Alpine and arctic polythermal glaciers develop permafrost below the upper cold-based glaciers and unfrozen rock below the warm based lower glacier parts. Glacier retreat and warming cause high rates of permafrost degradation and sometimes aggradation, sudden changes in hydro- and cryostatic pressures and fast changes in lateral ice-stresses on slopes (Krautblatter & Leith, 2015).

In SP3.3, we will develop generic mechanical models that undergo rapid thermal, mechanical and hydrological change. Release of ice stress and thermal conditions will be refined by additional information on glacier retreat (SP2.1) and on simulated basal ice temperatures (SP3.2). For the latter temperatures, SP3.3 will build on the finite-element Elmer/Ice applications calibrated to the benchmark glaciers for the last decades (SP3.2). Here, these simulations will be extended to cover the last century.

The presumable starting date is the end of the Little Ice Age (LIA). The modelling strategy is an initial equilibration run under LIA conditions followed by a forward simulation to present day forced by climatic data (e.g. ERA-20C, ERA5, CORDEX-CORE) downscaled to local AWS measurements (joint effort with SP3.1).
The centennial scope assures that the long-term memory is imprinted in the 3D temperature field. Accounting for both retreat and temperature information, we will develop generic rock-ice-mechanical models using the benchmark sites Vernagtferner and Hintereisferner.
The benchmark model will apply temperature-dependent changes in rock stability, ice stability in fractures and rock-ice interfaces as well as changes in hydro- and cryostatic forcing and lateral destabilisation due to reducing glacier support (Krautblatter et al. 2013).
Model development will occur on basis of discontinuum mechanical (UDEC) models that have been developed in recent research projects (Mamot et al., 2020). The generic mechanical models will be clustered to specific conditions indicated by glacier retreat and elevation change information outside glaciers to constrain models that anticipate the propensity of major hazards due to rock slope and debris slope failures in the recently ice-free slope and glacier forefields.

 

For specific information on the sub-project please contact: Prof. Dr. Michael Krautblatter, Ingenieurfakultät Bau, Geo & Umwelt, Arcisstr. 21, 80333 Munich, T: 089-289-25866, m.krautblatter@tum.de, http://www.landslides.geo.tum.de

Co-PIs: J. Fürst (FAU Geography), B. Etzelmüller, S. Westermann (Univ. Oslo)


Get to know our project affiliated PhD students


Felix Pfluger

felix.pfluger@tum.de

Want to learn more about Felix’ research? Click here to access a short video!

I am Felix. My research focuses on understanding the interaction between glaciers and permafrost in alpine environments. During paraglacial transition phases, as the landscape changes from ice to ice-free states, geomorphic activity is higher than usual. The relatively rapid and drastic change in thermal and hydrological characteristics predisposes rock slopes to a more fragile state. Furthermore, the evolution of permafrost in space is critical for the assessment of rock slope stability and potential hazards.

 

My aim is to develop a rock-ice mechanical model suitable to predict rock mass failure concomitant with changing cryospheric conditions. Besides rock mechanical laboratory experiments I will take advantage of the capabilities of the MOCCA group by having a joint field campaign using geophysics to explore glacial and permafrost conditions at a study site in Kaunertal. The knowledge of seismic, geoelectric and radar measurements will complement the permanent temperature monitoring of rock surface temperature to gain insights into the thermal characteristics at the study site. By coupling the mechanical model to a dynamic thermal model, we will be able to assess and predict rock mass failures in time.

 

Besides scientific goals you can hang out with me to blues rock music, even better to play some music together, to do some rock climbing or go fishing. As growing up in the Alps I am happy to work on a local study site in my home region.