Publications associées à Convective instability

Modular Multiplatform Compatible Air Measurement System (MoMuCAMS): a new modular platform for boundary layer aerosol and trace gas vertical measurements in extreme environments

Julia Schmale, Andrea Baccarini, Roman Pohorsky

The Modular Multiplatform Compatible Air Measurement System (MoMuCAMS) is a newly developed in situ aerosol and trace gas measurement platform for lower-atmospheric vertical profiling. MoMuCAMS has been primarily designed to be attached to a Helikite, a ru ...

2024

New Particle Formation Events Can Reduce Cloud Droplets in Boundary Layer Clouds at the Continental Scale

Athanasios Nenes, Spyros Pandis

New particle formation (NPF) substantially contributes to global cloud condensation nuclei (CCN), and their climate impacts. Individual NPF events are also thought to increase local CCN, cloud droplet number (CDN), and cloud albedo. High resolution simulat ...

Amer Geophysical Union2024

MoMuCAMS: A new modular platform for boundary layer aerosol and trace gas vertical measurements in extreme environments

Julia Schmale, Andrea Baccarini, Roman Pohorsky

The Modular Multiplatform Compatible Air Measurement System (MoMuCAMS) is a newly developed in situ aerosol and trace gas measurement payload for lower atmospheric vertical profiling in extreme environments. MoMuCAMS is a multiplatform compatible system, p ...

2023

Supercell Thunderstorms in the Alpine Region - From Weather Radar Observations to Idealized Modeling

Monika Feldmann

The high-impact nature and increasing occurrence of severe weather phenomena pushes forward research on their occurrence and improving our understanding thereof. Supercell thunderstorms are the focus of much severe convective research, as they represent on ...

EPFL2023

A Case Study on Drivers of the Isotopic Composition of Water Vapor at the Coast of East Antarctica

Michael Lehning, Armin Sigmund, Riqo Chaar

Stable water isotopes (SWIs) contain valuable information on the past climate and phase changes in the hydrologic cycle. Recently, vapor measurements in the polar regions have provided new insights into the effects of snow-related and atmospheric processes ...

AMER GEOPHYSICAL UNION2023

First-Principles Thermodynamics of CsSnI3

Nicola Marzari, Lorenzo Monacelli

CsSnI3 is a promising ecofriendly solution for energy harvesting technologies. It exists at room temperature in either a black perovskite polymorph or a yellow 1D double-chain, which irreversibly deteriorates in the air. In this work, we unveil the relativ ...

AMER CHEMICAL SOC2023

An analytical approximation of urban heat and dry islands and their impact on convection triggering

Gabriele Manoli, Kai Wang

It is well known that cities increase air and surface temperatures compared to their rural sur-roundings, the so-called urban heat island (UHI) effect. However, the associated changes in at-mospheric humidity (also known as urban dry island, UDI) and conve ...

ELSEVIER2022

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

Benzylammonium‐Mediated Formamidinium Lead Iodide Perovskite Phase Stabilization for Photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, David Lyndon Emsley, Hong Zhang, Felix Thomas Eickemeyer, Jovana Milic, Dominik Józef Kubicki, Dan Ren, Zaiwei Wang, Aditya Mishra, Masaud Hassan S Almalki, Anwar Qasem M Alanazi

There is an ongoing surge of interest in the use of formamidinium (FA) lead iodide perovskites in photovoltaics due to their exceptional optoelectronic properties. However, thermodynamic instability of the desired cubic perovskite (α-FAPbI3) phase at ambie ...

2021

Invariant states in inclined layer convection. Part 2. Bifurcations and connections between branches of invariant states

Tobias Schneider, Florian Reetz

Convection in a layer inclined against gravity is a thermally driven non-equilibrium system, in which both buoyancy and shear forces drive spatio-temporally complex flows. As a function of the strength of thermal driving and the angle of inclination, a mul ...

Cambridge University Press2020

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

Energetics of Radiatively Heated Ice-Covered Lakes

Alfred Johny Wüest, Damien Bouffard, Hugo Nicolás Ulloa Sánchez, Kraig Bates Winters

We derive the mechanical energy budget for shallow, ice-covered lakes energized by penetrative solar radiation. Radiation increases the available and background components of the potential energy at different rates. Available potential energy drives under- ...

2019

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

Implications of river intrusion and convective mixing on the spatial and temporal variability of under-ice CO2

Damien Bouffard, Natacha Tofield-Pasche

Ice-covered periods might significantly contribute to lake emissions at ice-melt, yet a comprehensive understanding of under-ice carbon dioxide (CO2) dynamics is still lacking. This study investigated the processes driving spatiotemporal patterns of under- ...

2019

Absolute/convective secondary instabilities and the role of confinement in free shear layers

François Gallaire, Cristobal Manuel Arratia Martinez, Saviz Mowlavi

We study the linear spatiotemporal stability of an infinite row of equal point vortices under symmetric confinement between parallel walls. These rows of vortices serve to model the secondary instability leading to the merging of consecutive (Kelvin-Helmho ...

2018

The effect of secondary ice production parameterization on the simulation of a cold frontal rainband

Athanasios Nenes

Secondary ice production via processes like rime splintering, frozen droplet shattering, and breakup upon ice hydrometeor collision have been proposed to explain discrepancies between in-cloud ice crystal and ice-nucleating particle numbers. To understand ...

Copernicus Publications2018

Highly Active Nanoperovskite Catalysts for Oxygen Evolution Reaction: Insights into Activity and Stability of Ba0.5Sr0.5Co0.8Fe0.2O2+delta and PrBaCo2O5+delta

Nicola Marzari, Ivano Eligio Castelli, Xi Cheng

It is shown that producing PrBaCo2O5+delta and Ba0.5Sr0.5Co0.8Fe0.2O2+delta nanoparticle by a scalable synthesis method leads to high mass activities for the oxygen evolution reaction (OER) with outstanding improvements by 10x and 50x, respectively, compar ...

WILEY-V C H VERLAG GMBH2018

Suppression of von Karman vortex streets past porous rectangular cylinders

François Gallaire, Pier Giuseppe Ledda, Francesco Viola, Lorenzo Siconolfi

Although the stability properties of the wake past impervious bluff bodies have been widely examined in the literature, similar analyses regarding the flow around and through porous ones are still lacking. In this work, the effect of the porosity and perme ...

2018

A severe hail storm in complex topography in Switzerland-Observations and processes

Nikola Besic, Urs Martin Germann

This paper studies a damaging hail storm that occurred on 6 June 2015 in the complex topography of Switzerland. The storm persisted for several hours and produced large hail resulting in significant damage. Storms of comparable severity occur on average on ...

ELSEVIER SCIENCE INC2018

Flow control of weakly non-parallel flows: application to trailing vortices

François Gallaire, Giacomo Valerio Iungo, Francesco Viola, Erica Pezzica

A general formulation is proposed to control the integral amplification factor of harmonic disturbances in weakly non-parallel amplifier flows. The sensitivity of the local spatial stability spectrum to a base-flow modification is first determined, general ...

Cambridge University Press2017