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Benjamin Walter

 

 

Fonction

collaborateur scientifique

  

Institut fédéral pour l'étude de la neige et des avalanches SLF
Flüelastrasse 11
7260 Davos Dorf

Site

Davos Da B 1 19

 

 

 

Research interests

Snow sciences:

- Snow and it's interaction with the atmosphere

- Drifting and blowing snow

- Snow microstructure

Fluid dynamics:

- Aeolian research (wind erosion, particle entrainment, shear stress partitioning, Owens hypothesis)

- Porous media flow (water flow through snow)

Instrumentation:

 

- Measuring snow properties, turbulent flow,  particle mass fluxes, fluid shear stress, solar radiation etc. to improve our understanding of complex environmental processes

- Improve and develop new instrumentation

 

 

Education

Nov 2008 – May 2012

Doctoral studies: WSL Institute for Snow and Avalanche Research SLF (WSL/SLF), Davos, Switzerland

PhD thesis: École polytechnique fédérale de Lausanne (EPFL), Switzerland, Supervisors: Prof. Marc Parlange and Prof. Michael Lehning

Degree: “Doctor of science”with distinction

Jun 2007 – Jun 2008

Diploma studies: Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg, Germany

Diploma thesis: Karlsruhe Institute of Technology (KIT), Germany

Supervisors: Prof. Dr. Wim De Boer, Prof Dr. Gerhard Willeke

Aug 2005 – Jul 2006

Exchange studies: Physics, Kungliga Tekniska Högskolan (KTH), Stockholm, Sweden

Aug 2002 – Jun 2008

Academic studies: Physics, Karlsruhe Institute of Technology (KIT), Germany

Degree: “Master in Physics” grade: ("sehr gut”)

 

 

Employments

Dec 2019 – now

Research associate (tenure-track): WSL/SLF, Group: Snow Physics

Task: Snow microstructure field measurements - ESA SnowLab NG

 

Oct 2018 – Nov. 2019

Research associate: WSL/SLF Group: Snow Processes,

Task: Greenland field work

 

July 2013 – Sep 2018

 

Research associate, Post-Doc: Physikalisch-Meteorologisches Observatorium Davos / World Radiation Centre (PMOD/WRC), Davos, Switzerland

Task: Space radiometer development, calibration, commissioning

Aug 2012 – Jun 2013

Post-Doc: WSL/SLF, Group: Snow Cover and Micrometeorology

Topic: Snow Physics: Microscale water flow through snow

Jun 2012 – Jul 2012

Guest Researcher: WSL/SLF, Group: Snow Cover and Micrometeorology

Topic: Fluid dynamics of particle laden flows

Jul 2008 – Oct 2008

Scientific assistant: Fraunhofer ISE, Freiburg, Germany

Topic: Improving thermography technique for solar cell characterization

 

Peer-reviewed publications

Walter B, Huwald H, Gehring J, Bühler Y, Lehning, M (2020) Radar measurements of blowing snow off a mountain ridge. Cryosphere, 14(6), 1779-1794. doi.org/10.5194/tc-14-1779-2020

Remesal O, Finsterle W, Walter B, Schmutz W (2018) Characterisation of a new carbon nanotube detector coating for solar absolute radiometers, Journal of Physics: Conference Series, Volume 972, doi.org/10.1088/1742-6596/972/1/012007

Walter B, Levesque P-L, Kopp G, Andersen B, Beck I, Finsterle W, Gyo M, Heuerman K, Koller S, Mingard N, Remesal Oliva A, Pfiffner D, Soder R, Spescha M, Suter M, Schmutz W (2017c) The CLARA/NORSAT-1 absolute radiometer: instrument design, characterization and calibration, Metrologia 54 (2017) 674–682

Walter B, Winkler R, Graber F, Finsterle W, Fox V, Li V, Schmutz W (2017b) Direct Solar Irradiance measurements with a Cryogenic Solar Absolute Radiometer, AIP Conference Proceedings 1810, 080007, doi.org/10.1063/1.4975538

Walter B, Voegeli C, Horender S (2017a) Estimating sediment mass fluxes on surfaces sheltered by live vegetation, Boundary-Layer Meteorol 163: 273. doi.org/10.1007/s10546-016-0224-z

Ball W, Schmutz W, Fehlmann A, Finsterle W, Walter B (2016) Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer 3 (PREMOS/PICARD) J. Space Weather Space Clim. 6 A32, doi.org/10.1051/swsc/2016026

Walter B, Fehlmann A, Finsterle W, Suter M, Soder R, Schmutz W (2014b) Spectrally integrated window transmittance measurements for a cryogenic solar absolute radiometer, Metrologia, Vol. 51, 344–349, iopscience.iop.org/article/10.1088/0026-1394/51/6/S344

Walter B, Horender S, Voegeli C, Lehning M (2014a) Experimental assessment of Owen’s second hypothesis on surface shear stress induced by a fluid during sediment saltation, Geophysical Research Letters, Vol. 41, doi.org/10.1002/2014GL061069

Gromke C, Horender S, Walter B, Lehning M (2014) Snow particle characteristics in the saltation layer, Journal of Glaciology, Vol. 60, No. 221, doi.org/10.3189/2014JoG13J079

Walter B, Horender S, Gromke C, Lehning M (2013) Measurements of the pore-scale water flow through snow using Fluorescent Particle Tracking Velocimetry, Water Resources Research, Vol. 49, 7448–7456, doi.org/10.1002/2013WR013960

Walter B, Gromke C, Leonard K, Manes C, Lehning M (2012c) Shear stress partitioning in live plant canopies and modifications to Raupach’s model. Boundary-Layer Meteorology, link.springer.com/article/10.1007%2Fs10546-012-9719-4

Walter B, Gromke C, Leonard K, Manes C, Lehning M (2012b) Spatio-temporal surface shear-stress variability in live plant canopies and cube arrays. Boundary-Layer Meteorology, link.springer.com/article/10.1007%2Fs10546-011-9690-5

Walter B, Gromke C, Leonard K, Clifton A, Lehning M (2012a) Spatially resolved skin friction velocity measurements using Irwin sensors: A calibration and accuracy analysis. Journal of Wind Engineering and Industrial Aerodynamics, doi.org/10.1016/j.jweia.2012.02.018

Gromke C, Manes C, Walter B, Lehning M, Guala M (2011) Aerodynamic roughness length of fresh snow. Boundary-Layer Meteorology, doi.org/10.1007/s10546-011-9623-3 

Kasemann M, Walter B, Warta W (2009) Reliable hot-spot classification in 10 ms using ultrafast lock-in thermography, Progress in photovoltaics: Research and applications, 17:441–450

Kasemann M, Grote D, Walter B, Kwapil W, Trupke T, Augarten Y, Bardos R A, Pink E, Abbott M D, Warta W (2008) Luminescence imaging for the detection of shunts on silicon solar cells, Progress in Photovoltaics: Research and Applications,16:4, 297-305

Kasemann M, Walter B, Meinhardt C, Ebser J, Kwapil W, Warta W (2008) Emissivity-corrected power loss calibration for lock-in thermography measurements on silicon solar cells, Journal of Applied Physics, 103:11, 113503-113503-8

 

Conference contributions

Walter B, Lehning, M (2018) Drifting and blowing snow investigations at different scales, International snow science workshop, 7-10 Dec, 2018, Niseko, Japan

Walter B, Schmutz W, Andersen B, Finsterle F, Kopp G, Koller S, Pfiffner D, Beattie A (2018) The latest TSI measurement results from CLARA on NorSat-1, European Geosciences Union (EGU) General Assembly, 8–13 April 2018, Vienna, Austria

Walter B, Finsterle F, Koller S, Levesque P-L, Pfiffner D, Schmutz W (2017) First TSI observations of the new Compact Lightweight Absolute Radiometer (CLARA), American Geophysical Union (AGU) fall meeting, 11-15 Dec. 2017, New Orleans, USA

Walter B, Finsterle F, Koller S, Levesque P-L, Pfiffner D, Schmutz W (2017) First Total Solar Irradiance observations from NORSAT-1/CLARA, 2nd Swiss Scientific Committee on Solar Terrestrial Physics (SCOSTEP) workshop, Oct. 10-11, Locarno, Switzerland

Walter B, Finsterle F, Koller S, Levesque P-L, Pfiffner D, Schmutz W (2017) The Compact Lightweight Absolute Radiometer (CLARA) for Total Solar Irradiance Measurements on the NORSAT-1 Satellite, European Geosciences Union (EGU) General Assembly, 23–28 April 2017, Vienna, Austria

Walter B, Winkler R, Finsterle F, Fehlmann A, Schmutz W (2016) Direct solar irradiance measurements with a cryogenic solar absolute radiometer, International Radiation Symposium, Apr. 17-22, Auckland, New Zealand

Walter B, Finsterle F, Koller S, Levesque P-L, Pfiffner D, Schmutz W (2016) A new generation of Compact Lightweight Absolute Radiometers (CLARA) for space borne TSI observations, 1st Swiss Scientific Committee on Solar Terrestrial Physics (SCOSTEP) workshop, Oct. 4-5, Bern, Switzerland

Walter B, Winkler R, Finsterle F, Fehlmann A, Schmutz W (2015) Terrestrial Solar Irradiance Measurements with a Cryogenic Solar Absolut Radiometer, Sun-Climate Symposium, Nov. 10-13, Savannah, USA

Walter B, Finsterle W, Winkler R, Fehlmann A, Schmutz W (2014) A Monitor to measure the Integral TRAnsmittance of windows (MITRA), NEWRAD Conference 24 - 27 June 2014, Helsinki, Finland

Walter B, Vögeli C, Horender S, Lehning M (2013), Experimental validation of a constant surface shear stress in particle saltation layers, 14th European Turbulence Conference, 1-3 September 2013, Lyon, France

Walter B, Horender S, Wever N, Gromke C, Lehning M (2012). Laser Induced Fluorescence - Particle Tracking Velocimetry (LIF- PTV) Measurements of Water Flow through Snow. International Snow Science Workshop (ISSW), Anchorage, USA

Walter B, Gromke C, Leonard K, Clifton A, Lehning M (2011) Measurements of surface shear stress distribution in live plant canopies. In: Proceedings of the 13th International Conference on Wind Engineering ICWE13, Amsterdam, The Netherlands

Walter B, Gromke C, Lehning M (2009) The SLF Boundary Layer Wind Tunnel - An Experimental Facility for Aerodynamical Investigations of Living Plants. In: Proceedings of the 2nd International Conference on Wind Effects on Trees, Freiburg, Germany

Walter B, Kasemann M, Grote D, Ebser J, Kwapil W, Warta W (2008) Verification of Power Loss Mechanisms Contributing to the Illuminated Lock-In Thermography (ILIT) Signal, 23rd European Photovoltaic Solar Energy Conference and Exhibition Valencia, Spain