Recherche

Afficher tous les résultats pour

Accueil

Personne

Alfred Johny Wüest

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (118)

Page 5 sur 6

Double-diffusive interfaces in Lake Kivu reproduced by direct numerical simulations

Alfred Johny Wüest

Double diffusion transforms uniform background gradients of temperature and salinity into "staircases" of homogeneous mixed layers that are separated by high-gradient interfaces. Direct numerical simulations (DNS) and microstructure measurements are two in ...

Amer Geophysical Union2014

Effects of non-uniform vertical constituent profiles on remote sensing reflectance of oligo- to mesotrophic lakes

Alfred Johny Wüest, Damien Bouffard, Vincent Maurice Nouchi

We investigate the impact on remote sensing reflectance by the vertical non-uniformities of water constituents. Reflectance simulated for 210 pairs of in situ measured chlorophyll-a and turbidity profiles (z = 0–20 m) from Lake Geneva are compared to simul ...

2018

Cold intrusions in Lake Baikal: Direct observational evidence for deep-water renewal

Alfred Johny Wüest

We studied cold, deep-water intrusions in the South Basin of Lake Baikal on the basis of 2 yr of data (December 1995-November 1997) from near-bottom and near-surface thermistor strings, monthly conductivity-temperature-depth (CTD) profiles, and a near-bott ...

American Society of Limnology and Oceanography2005

Is phosphorus retention in autochthonous lake sediments controlled by oxygen or phosphorus?

Alfred Johny Wüest, Beat Mueller

Eutrophication of various lakes on the Swiss Plateau was targeted in the 1980s by reducing external nutrient loading and installing aeration/oxygenation systems. For five eutrophic lakes, three of which have been artificially oxygenated and aerated for alm ...

American Society of Limnology and Oceanography2006

Effects of climate change on deep-water oxygen and winter mixing in a deep lake (Lake Geneva)

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Oxygen is the most important dissolved gas for lake ecosystems. Because low oxygen concentrations are an ongoing problem in many parts of the oceans and numerous lakes, oxygen depletion processes have been intensively studied over the last decades and were ...

2016

Coupling remote sensing and particle tracking to estimate trajectories in large water bodies

Tamar Kohn, Alfred Johny Wüest, Damien Bouffard, Chaojie Li

Propelled by the rapid development of equipment, technology and computational power, the monitoring and simulation of the hydrodynamics in lakes have steadily advanced. In contrast, water quality simulations are more difficult to implement, due to the diff ...

Elsevier2022

Eutrophication of ancient Lake Ohrid: Global warming amplifies detrimental effects of increased nutrient inputs

Alfred Johny Wüest, Beat Mueller

Lake Ohrid in southeastern Europe is one of the few ancient, long-lived lakes of the world, and contains more than 200 endemic species. On the basis of integrated monitoring of internal and external nutrient fluxes, a progressing eutrophication was detecte ...

American Society of Limnology and Oceanography2007

Application of Oxygen Eddy Correlation in Aquatic Systems

Alfred Johny Wüest

The eddy correlation technique is rapidly becoming an established method for resolving dissolved oxygen fluxes in natural aquatic systems. This direct and noninvasive determination of oxygen fluxes close to the sediment by simultaneously measuring the velo ...

Amer Meteorological Soc2010

Horizontal transport under wind-induced resonance in stratified waterbodies

Alfred Johny Wüest, Hugo Nicolás Ulloa Sánchez

Periodic winds acting on a stratified waterbody can amplify normal modes of motion and enhance the basin-scale circulation via resonance. Here, we use idealized largeeddy simulations to investigate the flow features and quantify the horizontal transport in ...

2020

Drivers of deep-water renewal events observed over 13 years in the South Basin of Lake Baikal

Alfred Johny Wüest

Lake Baikal, with a depth of 1637 m, is characterized by deep-water intrusions that bridge the near-surface layer to the hypolimnion. These episodic events transfer heat and oxygen over large vertical scales and maintain the permanent temperature stratifie ...

Amer Geophysical Union2015

Lake surface temperatures in a changing climate: a global sensitivity analysis

Alfred Johny Wüest

We estimate the effects of climatic changes, as predicted by six climate models, on lake surface temperatures on a global scale, using the lake surface equilibrium temperature as a proxy. We evaluate interactions between different forcing variables, the se ...

Springer Verlag2014

Prediction of surface temperature in lakes with different morphology using air temperature

Alfred Johny Wüest, Sebastiano Piccolroaz

Temperature of the surface layer of temperate lakes is reconstructed by means of a simplified model on the basis of air temperature alone. The comparison between calculated and observed data shows a remarkable agreement (Nash-Sutcliffe efficiency indices a ...

American Society of Limnology and Oceanography2014

Netto- Ökosystemproduktion in Seen - Bestimmung aus Monitoringdaten

Alfred Johny Wüest, Isabel Blanca Sophie Kiefer

PRODUCTION NETTE DE L’ÉCOSYSTÈME DANS LES LACS – DÉTERMINATION GRÂCE AUX DONNÉES DE MONITORING Les algues et les cyanobactéries se développent dans la couche de surface productive des lacs par l’absorption de CO2, de lumière et de nutriments. Malgré sa réu ...

2021

Particle dynamics in high-Alpine proglacial reservoirs modified by pumped-storage operation

Alfred Johny Wüest

Temperature and suspended particle distribution were surveyed and modeled in two high-Alpine reservoirs in Switzerland, connected by pumped-storage operations for similar to 30 years. Due to different glacier coverage of the catchments, the two reservoirs ...

Amer Geophysical Union2011

Physical and biogeochemical limits to internal nutrient loading of meromictic Lake Kivu

Alfred Johny Wüest, Natacha Pasche, Beat Mueller

Lake Kivu is one of the large African Rift lakes situated between the Democratic Republic of the Congo and Rwanda. In its permanently stratified hypolimnion, unusually high methane concentrations have increased further in recent decades. Because methanogen ...

American Society of Limnology and Oceanography2009

Entwicklung des Phosphorhaushalts und der Sauerstoffzehrung im Sempacher- und Baldeggersee

Alfred Johny Wüest

Um die Auswirkungen der hohen Sauerstoffzehrung im Tiefenwasser von Baldegger- und Sempachersee zu mildern, werden die Hypolimnia der beiden Seen seit 1982 bzw. 1984 künstlich belüftet. Während der Stagnation im Sommer wurde anfänglich in beiden Seen über ...

2012

Sediment oxygen uptake in Lake Geneva

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Between 1960 and 1980, the trophic state of Lake Geneva (situated between France and Switzerland) has changed from oligotrophic to eutrophic. Since then, the areal hypolimnetic oxygen demand of 1.31 gm-2 d-1 is now the highest measured in Switzerland and l ...

2014

Phosphate adsorption by mineral weathering particles in oligotrophic waters of high particle content

Alfred Johny Wüest, Beat Mueller

We investigated the interactions of dissolved reactive phosphorus (DRP) and dissolved nonreactive phosphorus (DNRP) with suspended and settled aquatic particles. The sorption to minerogenic particles from an alpine catchment collected in rivers, hydropower ...

Amer Geophysical Union2006

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

Meteolakes: An operational online three-dimensional forecasting platform for lake hydrodynamics

Alfred Johny Wüest, Damien Bouffard, Theo Baracchini

Environmental management depends on high-quality monitoring and its meaningful interpretation. The combination of local weather dynamics, regional anthropogenic stresses and global environmental changes make the evaluation of monitoring information in dyna ...

PERGAMON-ELSEVIER SCIENCE LTD2020