Publications associées à Mixed layer

Unraveling submesoscale processes associated with meso- and basin-scale gyres in Lake Geneva

In large lakes, basin-scale gyres and submesoscale eddies, i.e., rotating coherent water masses, play a key role in spreading biochemical materials and energy throughout the basin, thereby significantly impacting water quality. Due to their transient and s ...

EPFL2023

Chimney‐Like Intense Pelagic Upwelling in the Center of Basin‐Scale Cyclonic Gyres in Large Lake Geneva

David Andrew Barry, Ulrich Lemmin, Seyed Mahmood Hamze Ziabari, Rafael Sebastian Reiss, Mehrshad Foroughan

Basin-scale quasi-geostrophic gyres are common features of large lakes subject to Coriolis force. Cyclonic gyres are often characterized by dome-shaped thermoclines that form due to pelagic upwelling that takes place in their center. At present, the dynami ...

2023

Density currents driven by differential cooling in lakes: occurrence, dynamics and implications for littoral-pelagic exchange

Tomy Doda

Cross-shore flows exchange water laterally in lakes, with ecological implications for the ecosystem. One example is the convective circulation induced by differential cooling, also known as the thermal siphon. This lateral flow forms when the sloping sides ...

EPFL2022

Detecting submesoscale cold filaments in a basin-scale gyre in large, deep Lake Geneva (Switzerland/France)

David Andrew Barry, Ulrich Lemmin, Seyed Mahmood Hamze Ziabari, Amir Mehdi Razmi

Submesoscale filaments are a well-documented feature of oceanic flow fields. Based on the analysis of high-resolution 3D numerical simulations, field observations and remote sensing imagery, this study, carried out in Lake Geneva, Western Europe's largest ...

2022

Biomass burning and marine aerosol processing over the southeast Atlantic Ocean: a TEM single-particle analysis

Athanasios Nenes, Jonathan Marc Taylor, Lu Zhang

This study characterizes single-particle aerosol composition from filters collected during the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) and CLoud-Aerosol-Radiation Interaction and Forcing: Year 2017 (CLARIFY-2017) campaigns. I ...

Copernicus GmbH2022

Basin-scale gyres and mesoscale eddies in large lakes: A novel procedure for their detection and characterization, assessed in Lake Geneva

David Andrew Barry, Ulrich Lemmin, Seyed Mahmood Hamze Ziabari, Frédéric Charles Soulignac, Mehrshad Foroughan

In large lakes subject to the Coriolis force, basin-scale gyres and mesoscale eddies, i.e. rotating coherent water masses, play a key role in spreading biochemical materials and energy throughout the lake. In order to assess the spatial and temporal extent ...

2022

Seasonal phytoplankton and geochemical shifts in the subsurface chlorophyll maximum layer of a dimictic ferruginous lake

Hannah Elisa Chmiel

Subsurface chlorophyll maxima layers (SCML) are ubiquitous features of stratified aquatic systems. Availability of the micronutrient iron is known to influence marine SCML, but iron has not been explored in detail as a factor in the development of freshwat ...

2022

Persistence of bioconvection-induced mixed layers in a stratified lake

Alfred Johny Wüest, Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner

In situ observations of biophysical interactions in natural waters typically focus on physical mechanisms influencing biological activity. Yet, biological activity can also drive physical processes in aquatic environments. A community of photoautotrophic, ...

American Society of Limnology and Oceanography2021

Dynamics of wind-induced coastal upwelling and interbasin exchange in Lake Geneva during winter: Implications for deepwater renewal

Rafael Sebastian Reiss

Water quality in lakes is closely linked to hydrodynamics and often dominated by stratification, limiting the exchange between the epi- and hypolimnion. Thus, the vertical redistribution of biogeochemical tracers such as dissolved oxygen and nutrients by c ...

EPFL2021

Inhibited vertical mixing and seasonal persistence of a thin cyanobacterial layer in a stratified lake

Alfred Johny Wüest, Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner, Bieito Fernandez Castro

Harmful blooms of the filamentous cyanobacteria Planktothrix rubescens have become common in many lakes as they have recovered from eutrophication over the last decades. These cyanobacteria, capable of regulating their vertical position, often flourish at ...

2021

Evolution of stream and lake water temperature under climate change

Alfred Johny Wüest, Damien Bouffard, Wolf Hendrik Huwald, Adrien Michel, Bettina Schaefli, Carl Love Mikael Råman Vinnå, Martin Schmid

This report presents past observations and projects the future development of water temperature in Swiss lakes and rivers. Projections are made until the end of the 21st century using the CH2018 climate scenarios. Besides climate change effects on temperat ...

Federal Office for the Environment (FOEN)2021

Mixing processes and their ecological implications: From vertical to lateral variability in stratified lakes

Oscar Rodrigo Sepúlveda Steiner

The physical environment of natural waters influences biogeochemical processes to generate specific ecological niches, promoting biophysical interactions. Bacteria and phytoplankton communities can form spatial structures, such as layers and patches. The p ...

EPFL2020

Wintertime Coastal Upwelling in Lake Geneva: An Efficient Transport Process for Deepwater Renewal in a Large, Deep Lake

David Andrew Barry, Ulrich Lemmin, Andrea Cimatoribus, Rafael Sebastian Reiss

Combining field measurements, 3‐D numerical modeling, and Lagrangian particle tracking, we investigated wind‐driven, Ekman‐type coastal upwelling during the weakly stratified winter period 2017/2018 in Lake Geneva, Western Europe's largest lake (max. depth ...

2020

Convection‐Diffusion Competition Within Mixed Layers of Stratified Natural Waters

Alfred Johny Wüest, Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner

In stratified natural waters, convective processes tend to form nearly homogeneous mixed layers. However, shear‐driven turbulence generated by large‐scale background flow often rapidly smooths them through mixing with the stratified surroundings. Here we s ...

2019

Continuously-fed gravity currents propagating over a finite porous substrate

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Sara Venuleo

We present the results of laboratory investigations of continuously-fed density currents that propagate first over a smooth horizontal bed and then over a porous substrate of limited length. Inflow discharge, initial excess density, and substrate porositie ...

2019

Large-Eddy Simulations of the Steady Wintertime Antarctic Boundary Layer

Etienne Gabriel Henri Vignon

Observations of two typical contrasting weakly stable and very stable boundary layers from the winter at Dome C station, Antarctica, are used as a benchmark for two centimetre-scale-resolution large-eddy simulations. By taking the Antarctic winter, the eff ...

2019

Large-scale and meso-scale surface heat flux patterns of Lake Geneva

Abolfazl Irani Rahaghi

Diverse studies have confirmed the adverse impact of global climate change in lakes. In order to establish effective water quality management policies, it is essential to understand how the heat exchange between the atmosphere and the lake evolves under th ...

EPFL2018

Rainfall retrieval with commercial microwave links in Sao Paulo, Brazil

Timothy Hugh Raupach

In the last decade there has been a growing interest from the hydrometeorological community regarding rainfall estimation from commercial microwave link (CML) networks. Path-averaged rainfall intensities can be retrieved from the signal attenuation between ...

COPERNICUS GESELLSCHAFT MBH2018

Oxygen depletion in Lake Geneva

Robert Vincent Schwefel

Low oxygen concentrations remain a global concern for the ecological health of lakes. High nutrient inputs and climate-induced changes in stratification and mixing are anthropogenic threats which largely impact aquatic oxygen budgets and overall ecosystem ...

EPFL2017

Gyre formation in open and deep lacustrine embayments: The example of Lake Geneva, Switzerland

David Andrew Barry, Alfred Johny Wüest, Ulrich Lemmin, Damien Bouffard, Amir Mehdi Razmi, Robert Eduard Uittenbogaard

Numerical simulations were carried out to investigate gyres within open lacustrine embayments subjected to parallel-to-shore currents. In such embayments, gyre formation occurs due to flow separation at the embayment’s upstream edge. High momentum fluid fr ...

Springer Verlag2017