Publications associées à Océanographie physique

Turbulence and Heat exchange in the Near-Surface Boundary Layer over Patchy Snow

The atmospheric layer adjacent to the earth's surface is of crucial importance for weather models due to the exchange of energy between the surface and the atmosphere. This exchange is dependent on the various surface properties and influences the state of ...

EPFL2024

Polar oceans and sea ice in a changing climate

Julia Schmale, Hélène Paule Angot, Jenny Thomas

Polar oceans and sea ice cover 15% of the Earth’s ocean surface, and the environment is changing rapidly at both poles. Improving knowledge on the interactions between the atmospheric and oceanic realms in the polar regions, a Surface Ocean–Lower Atmospher ...

2023

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

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

Monitoring Mesoscale to Submesoscale Processes in Large Lakes with Sentinel-1 SAR Imagery: The Case of Lake Geneva

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

As in oceans, large-scale coherent circulations such as gyres and eddies are ubiquitous features in large lakes that are subject to the Coriolis force. They play a crucial role in the horizontal and vertical distribution of biological, chemical and physica ...

2022

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

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

Bifurcations at the Stability Transition of Earthquake Faulting

Carolina Giorgetti

Tectonic faults typically break in a single rupture mode within the range of styles from slow slip to dynamic earthquake failure. However, in increasingly well-documented instances, the same fault segment fails in both slow and fast modes within a short pe ...

AMER GEOPHYSICAL UNION2020

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

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

Model-based data analysis of the effect of winter mixing on primary production in a lake under reoligotrophication

Alfred Johny Wüest, Hugo Nicolás Ulloa Sánchez, Camille Roland Marie Minaudo, Shubham Krishna

Nutrient loading, in combination with climate change are important drivers of primary productivity in lakes. Understanding and forecasting future changes in primary production (PP) in response to local and global forcing are major challenges for developing ...

ELSEVIER2020

Enhanced Iron Solubility at Low pH in Global Aerosols

Athanasios Nenes, Kalliopi Violaki, Yan Feng

The composition and oxidation state of aerosol iron were examined using synchrotron-based iron near-edge X-ray absorption spectroscopy. By combining synchrotron-based techniques with water leachate analysis, impacts of oxidation state and mineralogy on aer ...

2018

The Influence of the Slope Angle of the Ocean–Land Mixed Propagation Path on the Lightning Electromagnetic Fields

Farhad Rachidi-Haeri, Keyhan Sheshyekani, Dongshuai Li

In this paper, lightning electromagnetic fields in the presence of an ocean-land mixed propagation path having different configurations are evaluated using a finite-element-based full-wave approach. The simulations are conducted considering lightning strik ...

Institute of Electrical and Electronics Engineers2015

Design and Characterization of a Full-Duplex Multiantenna System for WiFi Networks

Vaneet Aggarwal

In this paper, we present an experiment-and simulation-based study to evaluate the use of full duplex (FD) as a potential mode in practical IEEE 802.11 networks. To enable the study, we designed a 20-MHz multiantenna orthogonal frequency-division-multiplex ...

Ieee-Inst Electrical Electronics Engineers Inc2014

History and significance of the Morton number in hydraulic engineering

Michael Pfister

Two-phase air-water flows occur frequently in hydraulic engineering. Their characteristics, particularly the depth-averaged air concentrations, are of relevance for design. These must be known, for instance, to provide an adequate chute freeboard, or to av ...

Asce-Amer Soc Civil Engineers2014

Lightning Electromagnetic Fields and Their Induced Currents on Buried Cables. Part I: The Effect of an Ocean-Land Mixed Propagation Path

Farhad Rachidi-Haeri, Keyhan Sheshyekani

We use a full-wave finite-element-based solution of Maxwell's equations for the evaluation of lightning electromagnetic fields inside a vertically stratified, two-layer ground (ocean-land mixed propagation path) and their induced currents on the shield of ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Large Wind Farms and the Scalar Flux over an Heterogeneously Rough Land Surface

Marc Parlange, Chad Higgins, Marc Calaf Bracons

The influence of surface heterogeneities extends vertically within the atmospheric surface layer to the so-called blending height, causing changes in the fluxes of momentum and scalars. Inside this region the turbulence structure cannot be treated as horiz ...

Springer Verlag2014

Statistical mechanics of wind wave-induced erosion in shallow tidal basins: Inferences from the Venice Lagoon

Andrea Rinaldo

Wind wave-induced erosional effects are among the chief landscape-forming processes in tidal biomorphodynamics. Wave-driven bottom erosion, in fact, controls the equilibrium elevation and dynamics of subtidal and tidal flat surfaces, and the impact of wave ...

American Geophysical Union2013

Water Vapor and Heat Exchanges over Lakes

Nikki Vercauteren

Quantifying the interaction of the atmosphere and water surfaces is of great importance for water resources management, climate studies of ocean-atmosphere exchange and regional climate in coastal areas. Atmospheric dynamics over water surfaces have genera ...

EPFL2011

Two-phase hydrodynamic and sediment transport modeling of wave-generated sheet flow

David Andrew Barry, Roham Bakhtyar

This numerical investigation was carried out to advance mechanistic understanding of sediment transport under sheet flow conditions. An Euler-Euler coupled two-phase flow model was developed to simulate fluid-sediment oscillatory sheet flow. Since the conc ...

Elsevier2009