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Michael Lehning

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Publications associées (173)

Risks and Reliability in a Fully Renewable Switzerland

Michael Lehning, Albertus Christiaan Kruyt, Stuart John Bartlett, Annelen Kahl

In Switzerland, the government has made ambitious plans for a major energy transition. There is a planned phase out of nuclear facilities by mid-century, their capacity replaced by an expansion of hydroelectric infrastructure, new geothermal installations, ...

2015

Solving Richards Equation for snow improves snowpack meltwater runoff estimations in detailed multi-layer snowpack model

Michael Lehning, Nander Wever, Charles Fierz

The runoff from a snow cover during spring snowmelt or rain-on-snow events is an important factor in the hydrological cycle. In this study, three water balance schemes for the 1 dimensional physically-based snowpack model SNOWPACK are compared to lysimeter ...

European Geosciences Union2014

Elevation dependency of mountain snow depth

Michael Lehning

Elevation strongly affects quantity and distribution patterns of precipitation and snow. Positive elevation gradients were identified by many studies, usually based on data from sparse precipitation stations or snow depth measurements. We present a systema ...

Copernicus Gesellschaft Mbh2014

Modelling Small-Scale Drifting Snow with a Lagrangian Stochastic Model Based on Large-Eddy Simulations

Jan Overney, Marc Diebold, Marc Parlange, Gian-Duri Lieberherr, Michael Lehning

Observations of drifting snow on small scales have shown that, in spite of nearly steady winds, the snow mass flux can strongly fluctuate in time and space. Most drifting snow models, however, are not able to describe drifting snow accurately over short ti ...

Springer Verlag2014

Influence of snow cover properties on avalanche dynamics

Michael Lehning, Walter Steinkogler, Betty Sovilla

The destructive power of an avalanche depends, among other things, on the overall mass and the snow conditions in the avalanche path. So far, the knowledge on the effect of snow conditions on avalanche behavior is limited and largely qualitative. We invest ...

Elsevier Science Bv2014

Evaluation of modelled snow depth and snow water equivalent at three contrasting sites in Switzerland using SNOWPACK simulations driven by different meteorological data input

Michael Lehning, Charles Fierz

The knowledge of certain snow indices such as the number of snow days, maximum snow depth and snow water equivalent or the date of snow disappearance is important for many economical and ecological applications. However, snow data are frequently not availa ...

Elsevier2014

Orographic effects on snow deposition patterns in mountainous terrain

Michael Lehning, Alexis Berne, Marc Schneebeli Zeugin, Danny Eddy Scipion Castillo

Orographic lifting of air masses and other topographically modified flows induce cloud and precipitation formation at larger scales and preferential deposition of precipitation at smaller scales. In this study, we examine orographic effects on small-scale ...

Wiley-Blackwell2014

Snow particle characteristics in the saltation layer

Michael Lehning, Benjamin Andreas Walter

Shadowgraphy was employed to study snow saltation in boundary-layer wind tunnel experiments with fresh, naturally deposited snow. The shadowgraphy method allowed for a temporally and spatially high-resolution investigation of snow particle characteristics ...

Int Glaciol Soc2014

Model simulations of the modulating effect of the snow cover in a rain-on-snow event

Michael Lehning, Nander Wever, Tobias Jonas, Charles Fierz

In October 2011, the Swiss Alps underwent a marked rain-on-snow (ROS) event when a large snowfall on 8 and 9 October was followed by intense rain on 10 October. This resulted in severe flooding in some parts of Switzerland. Model simulations were carried o ...

European Geosciences Union2014

Experimental assessment of Owen's second hypothesis on surface shear stress induced by a fluid during sediment saltation

Michael Lehning, Benjamin Andreas Walter

A widely used, yet thus far unproven, fluid dynamical hypothesis originally presented by P. R. Owen 50years ago, states that the surface shear stress induced by a fluid on the ground during equilibrium sediment saltation is constant and independent of the ...

American Geophysical Union2014

Measurements of the pore-scale water flow through snow using Fluorescent Particle Tracking Velocimetry

Michael Lehning, Benjamin Andreas Walter

Fluorescent Particle Tracking Velocimetry (FPTV) measurements of the pore-scale water flow through the pore space of a wet-snow sample are presented to demonstrate the applicability of this measurement technique for snow. For the experiments, ice-cooled wa ...

American Geophysical Union2013

A comparison between two statistical and a physically-based model in snow water equivalent mapping

Michael Lehning, Tobias Jonas, Mathias Thierry Pierre Bavay

Snow water equivalent (SWE) estimates at the end of the winter season have been compared for the 2002–2006 period in a 200 km2 mountainous area in Switzerland, using three different models. The first model, ALPINE3D, is a physically based process-oriented ...

Elsevier2013

Snow-atmosphere interactions and hydrological consequences

Michael Lehning

Elsevier Sci Ltd2013

Event-driven deposition of snow on the Antarctic Plateau: analyzing field measurements with SNOWPACK

Michael Lehning, Charles Fierz

Antarctic surface snow has been studied by means of continuous measurements and observations over a period of 3 yr at Dome C. Snow observations include solid deposits in form of precipitation, diamond dust, or hoar, snow temperatures at several depths, rec ...

Copernicus Gesellschaft Mbh2013

Effect of winds in a mountain pass on turbine performance

Michael Lehning

Mountain passes are potentially advantageous sites for the deployment of wind turbines because of road links and electrical transmission infrastructure. However, relatively little is known about wind characteristics and turbine response in these environmen ...

Wiley-Blackwell2013

Statistical modelling of the snow depth distribution in open alpine terrain

Michael Lehning

The spatial distribution of alpine snow covers is characterised by large variability. Taking this variability into account is important for many tasks including hydrology, glaciology, ecology or natural hazards. Statistical modelling is frequently applied ...

European Geosciences Union2013

Response of snow cover and runoff to climate change in high Alpine catchments of Eastern Switzerland

Michael Lehning, Thomas Grünewald, Mathias Thierry Pierre Bavay

A model study on the impact of climate change on snow cover and runoff has been conducted for the Swiss Canton of Graubünden. The model Alpine3D has been forced with the data from 35 Automatic Weather Stations in order to investigate snow and runoff dynami ...

2013

Observations, theory, and modeling of the differential accumulation of Antarctic megadunes

Michael Lehning

Antarctic megadunes are characterized by significant spatial differences in accumulation rate, with higher accumulation on the windward side and near-zero accumulation on the lee side. This leads to spatial differences in physical properties of snow and su ...

Amer Geophysical Union2013

Seasonal simulation of drifting snow sublimation in Alpine terrain

Michael Lehning

We estimate seasonal drifting snow sublimation at a study site in the Swiss Alps with the numerical model Alpine3D using external wind fields from the Advanced Regional Prediction System on a high-resolution grid (10 m). Novel in the field of snow transpor ...

American Geophysical Union2013

Relative importance of advective heat transport and boundary layer decoupling in the melt dynamics of a patchy snow cover

Michael Lehning

For a patchy snow cover the advective heat transport and the near-surface boundary layer decoupling, which have an opposite effect on sensible heat transport onto the snow surface, are both expected to increase in magnitude. The main aim of this study is t ...

Elsevier Sci Ltd2013

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