Publications associées à Circulation atmosphérique

Urban boundary-layer flows in complex terrain: Dynamic interactions during a hot and dry summer season in Phoenix, Arizona

Anthropogenic modification of natural landscapes to urban environments impacts land-atmosphere interactions in the boundary layer. Ample research has demonstrated the effect of such landscape transitions on development of the urban heat island (UHI), but c ...

Wiley2024

Good enough: Intermediate complexity atmospheric models improve the representation of processes affecting seasonal snow

Dylan Stewart Reynolds

Snow plays a crucial role in processes regulating ecosystems, the climate, and human development. Mountain snowpack in particular has great relevance for downstream communities. Knowledge about the distribution and properties of the snowpack thus help in p ...

EPFL2024

Numerical study on the scale effect of tip vortex cavitation induced by incoming velocities and scale ratios

Mohamed Farhat, Huaiyu Cheng, Mohan Xu

Large eddy simulations of tip vortex cavitation (TVC) around an elliptical hydrofoil is performed to study its scale effect. A satisfying agreement is obtained between the numerical and experimental data. It indicates that the scale effect of TVC is remark ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Natural slicks on Lake Geneva: From small-scale effects to large-scale formation and distribution

Mehrshad Foroughan

Low wind speeds (< 4 m/s) are ubiquitous in many water bodies, yet the physical processes occurring at the air-water interface in this range are poorly understood. A notable example is smooth patches on the water surface, known as natural slicks, formed wh ...

EPFL2023

Snow Loss Into Leads in Arctic Sea Ice: Minimal in Typical Wintertime Conditions, but High During a Warm and Windy Snowfall Event

Julia Schmale, Marc Schneebeli Zeugin, Markus Frey

The amount of snow on Arctic sea ice impacts the ice mass budget. Wind redistribution of snow into open water in leads is hypothesized to cause significant wintertime snow loss. However, there are no direct measurements of snow loss into Arctic leads. We m ...

2023

CRYOWRF—Model Evaluation and the Effect of Blowing Snow on the Antarctic Surface Mass Balance

Varun Sharma, Michael Lehning, Franziska Gerber

The surface mass balance (SMB) of large polar ice sheets and of snow and ice surfaces in general are incompletely understood because of the complexity of processes involved. One such process, drifting and blowing snow, has only been considered in a very si ...

AMER GEOPHYSICAL UNION2023

Lightning Nowcasting Using Solely Lightning Data

Farhad Rachidi-Haeri, Marcos Rubinstein, Amirhossein Mostajabi

Lightning is directly or indirectly responsible for significant human casualties and property damage worldwide. A timely prediction of its occurrence can enable authorities and the public to take necessary precautionary actions resulting in diminishing the ...

MDPI2023

Convection of snow: when and why does it happen?

Michael Lehning, Mahdi Jafari

Convection of water vapor in snowpacks is supposed to have a major impact on snow density and microstructure profiles with strong implications for the thermal regime and snow stability. However, the process has never been directly measured and only recentl ...

FRONTIERS MEDIA SA2023

Exploring the link between austral stratospheric polar vortex anomalies and surface climate in chemistry-climate models

Nora Bergner

Extreme events in the stratospheric polar vortex can lead to changes in the tropospheric circulation and impact the surface climate on a wide range of timescales. The austral stratospheric vortex shows its largest variability in spring, and a weakened pola ...

Copernicus GmbH2022

Convective regimes induced by surface cooling and topography in stratified waterbodies

Damien Bouffard, Tomy Doda, Hugo Nicolás Ulloa Sánchez, Cintia Luz Ramon Casanas

Gravitational convection plays a significant role in the ventilation, heat and mass distribution of aquatic systems. This study investigates thermally driven convection resulting from heat loss at the air-water interface during cooling periods in freshwate ...

Iahr-Int Assoc Hydro-Environment Engineering Research2022

Flushing the Lake Littoral Region: The Interaction of Differential Cooling and Mild Winds

Damien Bouffard, Hugo Nicolás Ulloa Sánchez, Tomy Doda, Cintia Luz Ramon Casanas

The interaction of a uniform cooling rate at the lake surface with sloping bathymetry efficiently drives cross-shore water exchanges between the shallow littoral and deep interior regions. The faster cooling rate of the shallows results in the formation of ...

AMER GEOPHYSICAL UNION2022

Towards implementing new isotopes for environmental research:Redetermination of the 32Si half-life

Mario Aaron Veicht

The predicted climate changes on Earth will significantly impact the environment and human society. The climate patterns observed during the past centuries led to a better understanding of the driving forces for such changes. However, more studies using ne ...

EPFL2022

Arctic atmospheric mercury: Sources and changes

Hélène Paule Angot

Global anthropogenic and legacy mercury (Hg) emissions are the main sources of Arctic Hg contamination, primarily transported there via the atmosphere. This review summarizes the state of knowledge of the global anthropogenic sources of Hg emissions, and e ...

2022

Gyrokinetic simulations of turbulence and zonal flows driven by steep profile gradients using a delta-f approach with an evolving background Maxwellian

Laurent Villard, Stephan Brunner, Moahan Murugappan, Alberto Bottino, Ben McMillan

Long global gyrokinetic turbulence simulations are particularly challenging in situations where the system deviates strongly from its initial state and when fluctuation levels are high, for example, in strong gradient regions. For particle-in-cell simulati ...

2022

Growth, timing, & trajectory of vortices behind a rotating plate

Diego Francescangeli

The presence of aerodynamic vortices is widespread in nature. They can be found at small scales near the wing tip of flying insects or at bigger scale in the form of hurricanes, cyclones or even galaxies. They are identified as coherent regions of high vor ...

EPFL2022

Convection of water vapour in snowpacks

Varun Sharma, Michael Lehning, Mahdi Jafari

This paper studies numerically the convection of water vapour in snowpacks using an Eulerian-Eulerian two-phase approach. The convective water vapour transport in snow and its effects on snow density are often invoked to explain observed density profiles, ...

Cambridge University Press2022

Water soluble reactive phosphate (SRP) in atmospheric particles over East Mediterranean: The importance of dust and biomass burning events

Athanasios Nenes, Kalliopi Violaki, Christos Panagiotopoulos

The importance of dust and biomass burning episodes on the atmospheric concentration of water-soluble reactive phosphate (SRP) was determined in the eastern Mediterranean. SRP was measured with a new rapid real-time automated analytical system with a time ...

ELSEVIER2022

Radar processing techniques to study summer snowfall in the Sør Rondane Mountains, Antarctica

Alfonso Ferrone

Snowfall is one of the main positive contributors to the surface mass balance of the Antarctic ice sheet. There are several techniques to monitor solid precipitation on the continent. Among them, meteorological radars provide the means to characterize the ...

EPFL2022

Moored observations of turbulent mixing events in deep Lake Garda, Italy

Sebastiano Piccolroaz, Marco Toffolon

Deep water circulation and mixing processes are responsible for the transport of matter, nutrients and pollutants in deep lakes. Nevertheless, detailed continuous observations are rarely available. To overcome some of these deficiencies and with the aim of ...

2021

An overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) project: aerosol-cloud-radiation interactions in the southeast Atlantic basin

Athanasios Nenes

Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles, yet the fate of these particles and their influence on regional and global climate is poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their ...

Copernicus GmbH2021