Publications related to Synoptic scale meteorology

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

Brown carbon absorption in the Mediterranean basin from local and long-range transported biomass burning air masses

Athanasios Nenes

This study examines the impact of light absorption from biomass burning (BB) brown carbon (BrC) in the Mediterranean basin from local and distant fire incidents during a typical fire season in August 2019 and under severe fire activity in August 2021. The ...

Elsevier2023

Modeling Snow Saltation: The Effect of Grain Size and Interparticle Cohesion

Varun Sharma, Armin Sigmund, Michael Lehning, Daniela Brito Melo, Francesco Comola

The surface of the Earth is snow-covered at least seasonally over large areas. This snow surface is highly dynamic, particularly under the influence of strong winds. The motion of snow particles driven by the wind not only changes the snow cover but has im ...

2022

Aerobiology over the Southern Ocean – implications for bacterial colonization of Antarctica

Julia Schmale

Parts of the Antarctic are experiencing dramatic ecosystem change due to rapid and record warming, which may weaken biogeographic boundaries and dispersal barriers, increasing the risks of biological invasions. In this study, we collected air samples from ...

2022

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

A Characterisation of Alpine Mesocyclone Occurrence

Alexis Berne, Marco Gabella, Monika Feldmann, Urs Martin Germann

This work presents a characterisation of mesocyclone occurrence and frequency in the Alpine region, as observed from the Swiss operational radar network; 5 years of radar data are processed with a thunderstorm detection and tracking algorithm and subsequen ...

2021

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

Exploring the coupled ocean and atmosphere system with a data science approach applied to observations from the Antarctic Circumnavigation Expedition

Julia Schmale, Andrea Baccarini, Irina Gorodetskaya, Christel Sybille Hassler, Katherine Colby Leonard, Robin Lewis Modini, Jenny Thomas, Sebastian Johannes Heinz-Josef Landwehr, Alireza Moallemi, Fernando Perez Cruz

The Southern Ocean is a critical component of Earth's climate system, but its remoteness makes it challenging to develop a holistic understanding of its processes from the small scale to the large scale. As a result, our knowledge of this vast region remai ...

2021

Synoptic conditions and atmospheric moisture pathways associated with virga and precipitation over coastal Adelie Land in Antarctica

Alexis Berne, Etienne Gabriel Henri Vignon, Nicolas Jean François Jullien

Precipitation falling over the coastal regions of Antarctica often experiences low-level sublimation within the dry katabatic layer. The amount of water that reaches the ground surface is thereby considerably reduced. This paper investigates the synoptic c ...

2020

The impact of secondary ice production on Arctic stratocumulus

Athanasios Nenes, Georgia Sotiropoulou

In situ measurements of Arctic clouds frequently show that ice crystal number concentrations (ICNCs) are much higher than the number of available ice-nucleating particles (INPs), suggesting that secondary ice production (SIP) may be active. Here we use a L ...

Copernicus GmbH2020

Meridional and vertical variations of the water vapour isotopic composition in the marine boundary layer over the Atlantic and Southern Ocean

Julia Schmale, Sebastian Johannes Heinz-Josef Landwehr

Stable water isotopologues (SWIs) are useful tracers of moist diabatic processes in the atmospheric water cycle. They provide a framework to analyse moist processes on a range of timescales from large-scale moisture transport to cloud formation, precipitat ...

Copernicus GmbH2020

Density effects on solute release from the streambed

David Andrew Barry

Contaminants can be released to the stream from the bed by previous pollution events. The releasing contaminants may cause secondary pollution for a river, which impacts the river’s eco-environmental condition. By means of laboratory experiments and numeri ...

2020

Learning about the vertical structure of radar reflectivity using hydrometeor classes and neural networks in the Swiss Alps

Alexis Berne, Floortje Elisabeth Maria Van den Heuvel, Marco Gabella, Urs Martin Germann

The use of radar for precipitation measurement in mountainous regions is complicated by many factors, especially beam shielding by terrain features, which, for example, reduces the visibility of the shallow precipitation systems during the cold season. Whe ...

2020

Correction of CCI cloud data over the Swiss Alps using ground-based radiation measurements

Alexis Berne, Fanny Alexia Jeanneret

The validation of long-term cloud data sets retrieved from satellites is challenging due to their worldwide coverage going back as far as the 1980s. A trustworthy reference cannot be found easily at every location and every time. Mountainous regions presen ...

Copernicus GmbH2018

Hydrodynamics of a periodically wind‑forced small and narrow stratified basin: a large‑eddy simulation experiment

Alfred Johny Wüest, Damien Bouffard, Hugo Nicolás Ulloa Sánchez, Oscar Rodrigo Sepúlveda Steiner, Serban George Constantinescu, Kyoung Sik Chang

We report novel results of a numerical experiment designed for examining the basin-scale hydrodynamics that control the mass, momentum, and energy distribution in a daily wind-forced, small thermally-stratified basin. For this purpose, the 3-D Boussinesq e ...

2018

The tropical momentum map: a classification of toric log symplectic manifolds

Tudor Ratiu

We give a generalization of toric symplectic geometry to Poisson manifolds which are symplectic away from a collection of hypersurfaces forming a normal crossing configuration. We introduce the tropical momentum map, which takes values in a generalization ...

Springer Verlag2017

Distributed snow and rock temperature modelling in steep rock walls using Alpine3D

Michael Lehning, Nander Wever, Mathias Thierry Pierre Bavay

In this study we modelled the influence of the spatially and temporally heterogeneous snow cover on the surface energy balance and thus on rock temperatures in two rugged, steep rock walls on the Gemsstock ridge in the central Swiss Alps. The heterogeneous ...

Copernicus GmbH2017

How do patchy snow covers affect turbulent sensible heat fluxes? – Numerical analysis and experimental findings

Michael Lehning, Sebastian Schlögl

The surface energy balance of a snow cover significantly changes once the snow cover gets patchy. The substantial progress in knowledge about the surface energy balance of patchy snow covers is a mandatory requirement to reduce biases in flux parameterizat ...

2017

Squall: Scalable Real-time Analytics

Christoph Koch, Ioannis Klonatos, Aleksandar Vitorovic, Mohammad Dashti Rahmat Abadi, Mohamed Elsayed Mohamed Ahmed El Seidy, Daniel Espino Timón, Minh Khue Vu, Khayyam Mubariz Oglu Guliyev

Squall is a scalable online query engine that runs complex analytics in a cluster using skew-resilient, adaptive operators. Squall builds on state-of-the-art partitioning schemes and local algorithms, including some of our own. This paper presents the over ...

VLDB Endowment Inc.2016

Reliable Averages and Risky Extremes – Analysis of spatiotemporal variability in solar irradiance and persistent cloud cover patterns over Switzerland

Michael Lehning, Annelen Kahl, Juliette Ferial Blanchet, Albertus Christiaan Kruyt

With the perspective of Switzerland’s phase-out from nuclear energy, solar energy potential may take an important role for the country’s future in renewable energy. Based on 12 years of satellite-derived, spatially distributed data of daily average cloud f ...

Elsevier2016