Concept

Covariance des turbulences

Publications associées (52)

On the importance of the humidity flux for the surface mass balance in the accumulation zone of the Greenland Ice Sheet

It is highly uncertain how the humidity flux between the snow surface and the atmosphere contributes to the surface mass balance (SMB) of the interior Greenland Ice Sheet (GrIS). Due to sparse observations, evaluations of the simulated humidity flux are li ...

Gottingen2024

Towards continuous measurements of snow drift and sublimation in polar environments

Michael Lehning, Wolf Hendrik Huwald, John Martin Kolinski, Yael Frischholz, Armin Sigmund, Balthazar Allegri

In polar regions, and specifically in continental Antarctica, the local surface mass and energy balances can be largely controlled by snow transport in form of drifting and blowing snow particles, and sublimation both from the snow or ice surface and from ...

2023

Assessing sublimation during snow transport and sublimation effects on the isotopic composition of water vapor

Armin Sigmund

Sublimation influences the water storage in snow covers and glaciers, which is important for water use and projections of the sea level rise. Yet, it is challenging to quantify sublimation for large areas or in conditions of snow transport. In-situ measure ...

EPFL2023

Constraining Latent and Sensible Heat Fluxes during Drifting and Blowing Snow Events in Antarctica using in–situ Measurements and Large–Eddy Simulations

Varun Sharma, Michael Lehning, Wolf Hendrik Huwald, Jérôme François Sylvain Dujardin, Franziska Gerber, Daniela Brito Melo, Francesco Comola, Armin Sigmund

Reliable predictions of sea level rise require a quantitative understanding of the mass balance of the Antarctic ice sheet. Water vapor exchange between snow and the atmospheric boundary layer may be an important term in the mass balance equation but curre ...

2023

Low ozone dry deposition rates to sea ice during the MOSAiC field campaign: Implications for the Arctic boundary layer ozone budget

Julia Schmale, Ivo Fabio Beck, Hélène Paule Angot

Dry deposition to the surface is one of the main removal pathways of tropospheric ozone (O3). We quantified for the first time the impact of O3 deposition to the Arctic sea ice on the planetary boundary layer (PBL) O3 concentration and budget using year-ro ...

2023

Coupling of submeso-scale motion with near-surface turbulence over patchy snow cover

Michael Lehning

In spring, when the mountainous snow cover becomes patchy, the strong multi-scale surface heterogeneity influences atmospheric heat exchange processes. At valley scale, thermally driven winds advect warm air towards snow-covered regions at higher elevation ...

2023

Spatial Variability of Turbulent Mixing From an Underwater Glider in a Large, Deep, Stratified Lake

Alfred Johny Wüest, Damien Bouffard, Sébastien Lavanchy, Oscar Rodrigo Sepúlveda Steiner, Bieito Fernandez Castro, Alexander Lebaron Forrest

Recent efforts using microstructure turbulence measurements have contributed to our understanding of the overall energy budget in lakes and linkages to vertical fluxes. A paucity of lake-wide turbulence measurements hinders our ability to assess how repres ...

AMER GEOPHYSICAL UNION2023

Exploring alternative possibilities for sublimation measurements over snow and ice surfaces

Michael Lehning, Wolf Hendrik Huwald, Franziska Gerber, Armin Sigmund

Sublimation of snow is a major depletion mechanism, particularly in dry and windy environments such as high mountains or polar regions. Yet the quantification of the latent heat flux is a difficult task, and both measurements and estimates from models stil ...

2022

A Novel Method to Quantify Near-Surface Boundary-Layer Dynamics at Ultra-High Spatio-Temporal Resolution

Michael Lehning, Tobias Jonas, Dylan Stewart Reynolds, Michael Haugeneder

The lateral transport of heat above abrupt (sub-)metre-scale steps in land surface temperature influences the local surface energy balance. We present a novel experimental method to investigate the stratification and dynamics of the near-surface atmospheri ...

SPRINGER2022

Options to correct local turbulent flux measurements for large-scale fluxes using an approach based on large-eddy simulation

Peter Andreas Brugger

The eddy-covariance method provides the most direct estimates for fluxes between ecosystems and the atmosphere. However, dispersive fluxes can occur in the presence of secondary circulations, which can inherently not be captured by such single-tower measur ...

2021

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