Publications associées à Radar imageur

Snowfall microphysics: a dual-frequency and Doppler spectral radar perspective

Snowfall is an essential component of the hydrological cycle, as it is involved in most precipitation on Earth, either directly as snow falling to the ground or indirectly as rain melted from snow. At the same time, the ice phase of clouds and precipitatio ...

EPFL2023

Doppler spectra collected by weather and cloud radars during the POPE 2020 campaign at Princess Elisabeth Antarctica

Alexis Berne, Alfonso Ferrone

This repository contains the datasets of Doppler spectra collected by two meteorological radars in the vicinity of the Belgian research base Princess Elisabeth Antarctica (PEA). The measurement campaign has been conducted by the Environmental Remote S ...

Zenodo2023

Dual-frequency spectral radar retrieval of snowfall microphysics: a physics-driven deep-learning approach

Alexis Berne, Anne-Claire Marie Billault--Roux, Gionata Ghiggi

The use of meteorological radars to study snowfall microphysical properties and processes is well established, in particular via a few distinct techniques: the use of radar polarimetry, of multi-frequency radar measurements, and of the radar Doppler spectr ...

COPERNICUS GESELLSCHAFT MBH2023

AN UNSUPERVISED METHOD FOR THE DETECTION OF AND TRACKING OF TARGETS IN SPOTLIGHT MODE SAR IMAGES

Lloyd Haydn Hughes

Taking advantage of Capella's ability to dwell on a target for an extended period of time (nominally 30s) in its spotlight (SP) mode, an unsupervised methodology for detecting moving targets in this data is presented in this paper. By colourizing short seg ...

IEEE2023

Photonic radar for contactless vital sign detection

Yang Liu

Vital sign detection is used across ubiquitous scenarios in medical and health settings, and contact and wearable sensors have been widely deployed. However, they are unsuitable for patients with burn wounds or infants with insufficient areas for attachmen ...

Nature Publishing Group2023

Wind Transport of Snow Impacts Ka- and Ku-band Radar Signatures on Arctic Sea Ice

Marc Schneebeli Zeugin, David Nicholas Wagner

Wind transport alters the snow topography and microstructure on sea ice through snow redistribution controlled by deposition and erosion. The impact of these processes on radar signatures is poorly understood. Here, we examine the effects of snow redistrib ...

2023

Radar and ground-level measurements of clouds and precipitation collected during the POPE 2020 campaign at Princess Elisabeth Antarctica

Alexis Berne, Alfonso Ferrone

The datasets presented in this article were collected during a four-months measurement campaign at the Belgian research base Princess Elisabeth Antarctica (PEA). The campaign, named PEA Orographic Precipitation Experiment (POPE), was conducted by the Envir ...

2023

Leveraging Self-Supervision for Cross-Domain Crowd Counting

Pascal Fua, Nikita Durasov, Weizhe Liu

State-of-the-art methods for counting people in crowded scenes rely on deep networks to estimate crowd density. While effective, these data-driven approaches rely on large amount of data annotation to achieve good performance, which stops these models from ...

IEEE COMPUTER SOC2022

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

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

Context-Aware Image Super-Resolution Using Deep Neural Networks

Mohammad Saeed Rad

Image super-resolution is a classic ill-posed computer vision and image processing problem, addressing the question of how to reconstruct a high-resolution image from its low-resolution counterpart. Current state-of-the-art methods have improved the perfor ...

EPFL2021

Leveraging meteorological radars to investigate the influence of atmospheric dynamics on snowfall microphysics

Josué Etienne Gehring

Precipitation is the result of a chain of meteorological processes ranging from the large- to the micro-scale. While the transport of moisture and lifting mechanisms leading to cloud formation are mostly governed by dynamical processes, the formation and g ...

EPFL2021

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

Microphysics and dynamics of snowfall associated with a warm conveyor belt over Korea

Alexis Berne, Josué Etienne Gehring, Nikola Besic, Etienne Gabriel Henri Vignon, Nicolas Jean François Jullien

On 28 February 2018, 57mm of precipitation associated with a warm conveyor belt (WCB) fell within 21 h over South Korea. To investigate how the large-scale circulation influenced the microphysics of this intense precipitation event, we used radar measureme ...

Copernicus Publications2020

Radar measurements of blowing snow off a mountain ridge

Michael Lehning, Wolf Hendrik Huwald, Josué Etienne Gehring, Benjamin Andreas Walter

Modelling and forecasting wind-driven redistribution of snow in mountainous regions with its implications on avalanche danger, mountain hydrology or flood hazard is still a challenging task often lacking in essential details. Measurements of drifting and b ...

2020

Dynamic Differential Reflectivity Calibration Using Vertical Profiles in Rain and Snow

Alexis Berne, Alfonso Ferrone

The accuracy required for a correct interpretation of differential reflectivity (ZDR) is typically estimated to be between 0.1 and 0.2 dB. This is achieved through calibration, defined as the identification of the constant or time-varying offset to be subt ...

2020

Nonlinear states and dynamics in a synthetic frequency dimension

Tobias Kippenberg, Aleksandr Tusnin, Alexey Tikan

Recent advances in the study of synthetic dimensions revealed a possibility to employ the frequency space as an additional degree of freedom which allows for investigating and exploiting higher-dimensional phenomena in a priori low-dimensional systems. How ...

AMER PHYSICAL SOC2020

Nonlinear effects in synthetic frequency dimension created by electro-optical modulation of a ring resonator

Tobias Kippenberg, Aleksandr Tusnin, Alexey Tikan

We numerically investigate the nonlinear dynamics of an optical resonator with electro-optical modulation. In this system we discover chimera states and their transition into new stable states with increasing modulation amplitude. Bifurcation analysis reve ...

IEEE2020

Monopulse Beam Synthesis Using a Sparse Single Layer of Weights

Semin Kwak

A conventional monopulse radar system uses three beams, namely, sum beam, elevation difference beam, and azimuth difference beam, which require different layers of weights to synthesize each beam independently. Since the multilayer structure increases the ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019