TY  - JOUR
A1  - Bühler, Yves
A1  - Christen, Marc
A1  - Kowalski, Julia
A1  - Bartelt, Perry
T1  - Sensitivity of snow avalanche simulations to digital elevation model quality and resolution
JF  - Annals of Glaciology
N2  - Digital elevation models (DEMs), represent the three-dimensional terrain and are the basic input for numerical snow avalanche dynamics simulations. DEMs can be acquired using topographic maps or remote-sensing technologies, such as photogrammetry or lidar. Depending on the acquisition technique, different spatial resolutions and qualities are achieved. However, there is a lack of studies that investigate the sensitivity of snow avalanche simulation algorithms to the quality and resolution of DEMs. Here, we perform calculations using the numerical avalance dynamics model RAMMS, varying the quality and spatial resolution of the underlying DEMs, while holding the simulation parameters constant. We study both channelized and open-terrain avalanche tracks with variable roughness. To quantify the variance of these simulations, we use well-documented large-scale avalanche events from Davos, Switzerland (winter 2007/08), and from our large-scale avalanche test site, Valĺee de la Sionne (winter 2005/06). We find that the DEM resolution and quality is critical for modeled flow paths, run-out distances, deposits, velocities and impact pressures. Although a spatial resolution of ~25 m is sufficient for large-scale avalanche modeling, the DEM datasets must be checked carefully for anomalies and artifacts before using them for dynamics calculations.
KW  - snow
KW  - avalanche
Y1  - 2011
SN  - 1727-5644
VL  - 52
IS  - 58
SP  - 72
EP  - 80
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Kowalski, Julia
T1  - Mathematische Murgangmodellierung
JF  - Newsletter Naturgefahren
Y1  - 2008
VL  - 2008
IS  - 2
SP  - 4
EP  - 5
ER  - 
TY  - THES
A1  - Kowalski, Julia
T1  - Two-phase Modeling of Debris Flows
Y1  - 2008
SN  - 978-3-86664-524-0
N1  - Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 17827, 2008
PB  - Mensch und Buch
CY  - Berlin
ER  - 
TY  - GEN
A1  - Kowalski, Julia
T1  - Dynamics of Granular Material Avalanches and Numerical Approximations of Savage-Hutter Models
Y1  - 2004
N1  - Diploma Thesis, University of Augsburg
ER  - 
TY  - CHAP
A1  - Kowalski, Julia
T1  - Numerical Debris Flow Simulation
T2  - Schweizer Numerik Kolloquium : Book of Abstracts 12. April 2006
Y1  - 2006
ER  - 
TY  - CHAP
A1  - Kowalski, Julia
A1  - McArdell, B. W.
A1  - Bartelt, Perry
T1  - A comparison of two approaches to modeling multiphase gravity currents
T2  - Geophysical Research Abstracts
Y1  - 2006
N1  - A-08738
VL  - 8
ER  - 
TY  - CHAP
A1  - Kowalski, Julia
A1  - Bartelt, Perry
A1  - McElwaine, J.
T1  - Two-phase debris flow modeling
T2  - Geophysical Research Abstracts
Y1  - 2007
N1  - A-08119
ER  - 
TY  - CHAP
A1  - Kowalski, Julia
A1  - McElwaine, J.
T1  - Two-phase debris flow modeling
T2  - Geophysical Research Abstracts
Y1  - 2008
N1  - A-01048
ER  - 
TY  - CHAP
A1  - Kowalski, Julia
A1  - Bugnion, Louis
T1  - An extended shallow flow theory for natural debris flows
Y1  - 2009
N1  - 2009 Portland GSA Annual Meeting (18-21 October 2009); Geological Society of America
VL  - 41
IS  - 7
SP  - 609
EP  - 609
ER  - 
TY  - CHAP
A1  - Olaru, Alexandra Maria
A1  - Kowalski, Julia
A1  - Sethi, Vaishali
A1  - Blümich, Bernhard
T1  - Fluid Transport in Porous Media probed by Relaxation-Exchange NMR
T2  - 2011 Fall Meeting, AGU, San Francisco, Calif., 5-9 Dec.
Y1  - 2011
N1  - H12B-07; American Geophysical Union
ER  - 
TY  - CHAP
A1  - Niedermeier, H.
A1  - Clemens, J.
A1  - Kowalski, Julia
A1  - Macht, S.
A1  - Heinen, D.
A1  - Hoffmann, R.
A1  - Linder, Peter
T1  - Navigation system for a research ice probe for antarctic glaciers
T2  - IEEE/ION Position, Location and Navigation Symposium (PLANS) ; 5-8 May 2014, Monterey, Calif.
Y1  - 2014
SN  - 978-1-4799-3319-8
SP  - 959
EP  - 975
PB  - IEEE
CY  - Piscataway, NJ
ER  - 
TY  - JOUR
A1  - Konstantinidis, Konstantinos
A1  - Flores Martinez, Claudio
A1  - Dachwald, Bernd
A1  - Ohndorf, Andreas
A1  - Dykta, Paul
A1  - Bowitz, Pascal
A1  - Rudolph, Martin
A1  - Digel, Ilya
A1  - Kowalski, Julia
A1  - Voigt, Konstantin
A1  - Förstner, Roger
T1  - A lander mission to probe subglacial water on Saturn's moon enceladus for life
JF  - Acta astronautica
Y1  - 2015
SN  - 1879-2030 (E-Journal); 0094-5765 (Print)
VL  - Vol. 106
SP  - 63
EP  - 89
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Mikucki, Jill
A1  - Tulaczyk, Slawek
A1  - Digel, Ilya
A1  - Espe, Clemens
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Kowalski, Julia
A1  - Xu, Changsheng
T1  - IceMole : A maneuverable probe for clean in situ analysis and sampling of subsurface ice and subglacial aquatic ecosystems
JF  - Annals of Glaciology
N2  - There is significant interest in sampling subglacial environments for geobiological studies, but they are difficult to access. Existing ice-drilling technologies make it cumbersome to maintain microbiologically clean access for sample acquisition and environmental stewardship of potentially fragile subglacial aquatic ecosystems. The IceMole is a maneuverable subsurface ice probe for clean in situ analysis and sampling of glacial ice and subglacial materials. The design is based on the novel concept of combining melting and mechanical propulsion. It can change melting direction by differential heating of the melting head and optional side-wall heaters. The first two prototypes were successfully tested between 2010 and 2012 on glaciers in Switzerland and Iceland. They demonstrated downward, horizontal and upward melting, as well as curve driving and dirt layer penetration. A more advanced probe is currently under development as part of the Enceladus Explorer (EnEx) project. It offers systems for obstacle avoidance, target detection, and navigation in ice. For the EnEx-IceMole, we will pay particular attention to clean protocols for the sampling of subglacial materials for biogeochemical analysis. We plan to use this probe for clean access into a unique subglacial aquatic environment at Blood Falls, Antarctica, with return of a subglacial brine sample.
KW  - Antarctic Glaciology
KW  - Extraterrestrial Glaciology
KW  - Glaciological instruments and methods
KW  - Subclacial exploration
KW  - Subglacial lakes
Y1  - 2014
U6  - http://dx.doi.org/10.3189/2014AoG65A004
SN  - 1727-5644
VL  - 55
IS  - 65
SP  - 14
EP  - 22
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Schüller, K.
A1  - Kowalski, Julia
A1  - Raback, P.
T1  - Curvilinear melting – A preliminary experimental and numerical study
JF  - International Journal of Heat and Mass Transfer
N2  - When exploring glacier ice it is often necessary to take samples or implement sensors at a certain depth underneath the glacier surface. One way of doing this is by using heated melting probes. In their common form these devices experience a straight one-dimensional downwards motion and can be modeled by standard close-contact melting theory. A recently developed melting probe however, the IceMole, achieves maneuverability by simultaneously applying a surface temperature gradient to induce a change in melting direction and controlling the effective contact-force by means of an ice screw to stabilize its change in attitude. A modeling framework for forced curvilinear melting does not exist so far and will be the content of this paper. At first, we will extend the existing theory for quasi-stationary close-contact melting to curved trajectories. We do this by introducing a rotational mode. This additional unknown in the system implies yet the need for another model closure. Within this new framework we will focus on the effect of a variable contact-force as well as different surface temperature profiles. In order to solve for melting velocity and curvature of the melting path we present both an inverse solution strategy for the analytical model, and a more general finite element framework implemented into the open source software package ELMER. Model results are discussed and compared to experimental data conducted in laboratory tests.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.09.046
SN  - 0017-9310
IS  - 92
SP  - 884
EP  - 892
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kowalski, Julia
A1  - Linder, Peter
A1  - Zierke, S.
A1  - Wulfen, B. van
A1  - Clemens, J.
A1  - Konstantinidis, K.
A1  - Ameres, G.
A1  - Hoffmann, R.
A1  - Mikucki, J.
A1  - Tulaczyk, S.
A1  - Funke, O.
A1  - Blandfort, D.
A1  - Espe, Clemens
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Hiecker, S.
A1  - Plescher, Engelbert
A1  - Schöngarth, Sarah
A1  - Dachwald, Bernd
A1  - Digel, Ilya
A1  - Artmann, Gerhard
A1  - Eliseev, D.
A1  - Heinen, D.
A1  - Scholz, F.
A1  - Wiebusch, C.
A1  - Macht, S.
A1  - Bestmann, U.
A1  - Reineking, T.
A1  - Zetzsche, C.
A1  - Schill, K.
A1  - Förstner, R.
A1  - Niedermeier, H.
A1  - Szumski, A.
A1  - Eissfeller, B.
A1  - Naumann, U.
A1  - Helbing, K.
T1  - Navigation technology for exploration of glacier ice with maneuverable melting probes
JF  - Cold Regions Science and Technology
N2  - The Saturnian moon Enceladus with its extensive water bodies underneath a thick ice sheet cover is a potential candidate for extraterrestrial life. Direct exploration of such extraterrestrial aquatic ecosystems requires advanced access and sampling technologies with a high level of autonomy. A new technological approach has been developed as part of the collaborative research project Enceladus Explorer (EnEx). The concept is based upon a minimally invasive melting probe called the IceMole. The force-regulated, heater-controlled IceMole is able to travel along a curved trajectory as well as upwards. Hence, it allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. The development of such a navigational system has been the focal part of the EnEx project. The original IceMole has been further developed to include relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection integrated through a high-level sensor fusion. This paper describes the EnEx technology and discusses implications for an actual extraterrestrial mission concept.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.coldregions.2015.11.006
SN  - 0165-232X
IS  - 123
SP  - 53
EP  - 70
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Konstantinidis, K.
A1  - Kowalski, Julia
A1  - Martinez, C. F.
A1  - Dachwald, Bernd
A1  - Ewerhart, D.
A1  - Förstner, R.
T1  - Some necessary technologies for in-situ astrobiology on enceladus
T2  - Proceedings of the International Astronautical Congress
Y1  - 2015
SN  - 978-151081893-4
N1  - 6th International Astronautical Congress 2015: Space - The Gateway for Mankind's Future, IAC 2015; Jerusalem; Israel; 12 October 2015 through 16 October 2015
SP  - 1354
EP  - 1372
ER  - 
TY  - JOUR
A1  - Lyons, W. Berry
A1  - Mikucki, Jill A.
A1  - German, Laura A.
A1  - Welch, Kathleen A.
A1  - Welch, Susan A.
A1  - Gardener, Christopher B.
A1  - Tulaczyk, Slawek M.
A1  - Pettit, Erin C.
A1  - Kowalski, Julia
A1  - Dachwald, Bernd
T1  - The Geochemistry of Englacial Brine from Taylor Glacier, Antarctica
JF  - Journal of Geophysical Research: Biogeosciences
Y1  - 2019
U6  - http://dx.doi.org/10.1029/2018JG004411
SN  - 2169-8961
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Campen, R.
A1  - Kowalski, Julia
A1  - Lyons, W.B.
A1  - Tulaczyk, S.
A1  - Dachwald, Bernd
A1  - Pettit, E.
A1  - Welch, K. A.
A1  - Mikucki, J.A.
T1  - Microbial diversity of an Antarctic subglacial community and high‐resolution replicate sampling inform hydrological connectivity in a polar desert
JF  - Environmental Microbiology
Y1  - 2019
U6  - http://dx.doi.org/10.1111/1462-2920.14607
SN  - 1462-2920
IS  - accepted article
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - CHAP
A1  - Waldmann, Christoph
A1  - Vera, Jean-Pierre de
A1  - Dachwald, Bernd
A1  - Strasdeit, Henry
A1  - Sohl, Frank
A1  - Hanff, Hendrik
A1  - Kowalski, Julia
A1  - Heinen, Dirk
A1  - Macht, Sabine
A1  - Bestmann, Ulf
A1  - Meckel, Sebastian
A1  - Hildebrandt, Marc
A1  - Funke, Oliver
A1  - Gehrt, Jan-Jöran
T1  - Search for life in ice-covered oceans and lakes beyond Earth
T2  - 2018 IEEE/OES Autonomous Underwater Vehicle Workshop, Proceedings November 2018, Article number 8729761
N2  - The quest for life on other planets is closely connected with the search for water in liquid state. Recent discoveries of deep oceans on icy moons like Europa and Enceladus have spurred an intensive discussion about how these waters can be accessed. The challenge of this endeavor lies in the unforeseeable requirements on instrumental characteristics both with respect to the scientific and technical methods. The TRIPLE/nanoAUV initiative is aiming at developing a mission concept for exploring exo-oceans and demonstrating the achievements in an earth-analogue context, exploring the ocean under the ice shield of Antarctica and lakes like Dome-C on the Antarctic continent.
KW  - Planetary exploration
KW  - Jupiter
KW  - ice moons
KW  - underwater vehicle
KW  - Antarctica
Y1  - 2018
U6  - http://dx.doi.org/10.1109/AUV.2018.8729761
ER  - 
TY  - JOUR
A1  - German, Laura
A1  - Mikucki, Jill A.
A1  - Welch, Susan A.
A1  - Welch, Kathleen A.
A1  - Lutton, Anthony
A1  - Dachwald, Bernd
A1  - Kowalski, Julia
A1  - Heinen, Dirk
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Espe, Clemens
A1  - Lyons, W. Berry
T1  - Validation of sampling antarctic subglacial hypersaline waters with an electrothermal ice melting probe (IceMole) for environmental analytical geochemistry
JF  - International Journal of Environmental Analytical Chemistry
N2  - Geochemical characterisation of hypersaline waters is difficult as high concentrations of salts hinder the analysis of constituents at low concentrations, such as trace metals, and the collection of samples for trace metal analysis in natural waters can be easily contaminated. This is particularly the case if samples are collected by non-conventional techniques such as those required for aquatic subglacial environments. In this paper we present the first analysis of a subglacial brine from Taylor Valley, (~ 78°S), Antarctica for the trace metals: Ba, Co, Mo, Rb, Sr, V, and U. Samples were collected englacially using an electrothermal melting probe called the IceMole. This probe uses differential heating of a copper head as well as the probe’s sidewalls and an ice screw at the melting head to move through glacier ice. Detailed blanks, meltwater, and subglacial brine samples were collected to evaluate the impact of the IceMole and the borehole pump, the melting and collection process, filtration, and storage on the geochemistry of the samples collected by this device. Comparisons between melt water profiles through the glacier ice and blank analysis, with published studies on ice geochemistry, suggest the potential for minor contributions of some species Rb, As, Co, Mn, Ni, NH4+, and NO2−+NO3− from the IceMole. The ability to conduct detailed chemical analyses of subglacial fluids collected with melting probes is critical for the future exploration of the hundreds of deep subglacial lakes in Antarctica.
Y1  - 2021
U6  - http://dx.doi.org/10.1080/03067319.2019.1704750
SN  - 0306-7319
VL  - 101
IS  - 15
SP  - 2654
EP  - 2667
PB  - Taylor & Francis
CY  - London
ER  -