Publications de Valentin Simeonov

Translational screening platform to evaluate chemotherapy in combination with focal therapy for retinoblastoma

Valentin Simeonov, Paul Joseph Dyson, Fabien Kuttler, Patrik Aouad, Irina Sinenko

Retinoblastoma is the most common pediatric eye cancer. It is currently treated with a limited number of drugs, adapted from other pediatric cancer treatments. Drug toxicity and relapse of the disease warrant new therapeutic strategies for these young pati ...

WILEY2023

Raman lidar in operational meteorology

Bertrand Calpini, Valentin Simeonov, Todor Dinoev, Ilya Serikov

Water vapor and temperature spatial distribution and their temporal evolution are among the most important parameters in numerical weather forecasting and climate models. The operational relative humidity/temperature profiling in meteorology is carried out ...

SPIE-INT SOC OPTICAL ENGINEERING2018

First principle calibration of water vapor Raman lidars

Valentin Simeonov

A new method for calibration of water vapor Raman lidars based on first principles is proposed. The calibration constant of a Raman lidar is derived from a set of water vapor and nitrogen Raman backscatter signals measured with the lidar receiver in a cell ...

Spie-Int Soc Optical Engineering2017

Absolutely calibrated Raman lidar as a reference tool in atmospheric humidity profiling

Valentin Simeonov

Raman lidars exploit the proportionality between the intensity of scattered by a Raman process laser radiation and the number density of the scattering molecules to derive water vapor mixing ratio profile. Water vapor/air mixing ratio is directly proportio ...

2014

Instrumental correction of the uneven PMT aging effect on the calibration constant of a water vapor Raman lidar

Bertrand Calpini, Valentin Simeonov, Salomon Fastig

The water vapor profile derived from Raman lidar measurements is obtained by taking the ratio of water vapor and nitrogen Raman-shifted signals. The proportionality factor that converts the signal ratio to water vapor/air mixing ratio is referred to as lid ...

Spie-Int Soc Optical Engineering2014

Are atmospheric surface layer f lows ergodic?

Valentin Simeonov, Martin Froidevaux, Marc Parlange, Chad Higgins, Gabriel George Katul

The transposition of atmospheric turbulence statistics from the time domain, as conventionally sampled in field experiments, is explained by the so-called ergodic hypothesis. In micrometeorology, this hypothesis assumes that the time average of a measured ...

American Geophysical Union2013

Raman Lidar for Meteorological Observations, RALMO - Part 2: Validation of water vapor measurements

Bertrand Calpini, Valentin Simeonov

The Raman Lidar for Meteorological Observations (RALMO) was installed at the MeteoSwiss Regional Center of Payerne, Switzerland, in summer 2008. One of its aims is to provide continuous vertical profiles of tropospheric water vapor during day and night at ...

European Geosciences Union2013

Measured and Estimated Water Vapor Advection in the Atmospheric Surface Layer

Valentin Simeonov, Martin Froidevaux, Marc Parlange, Chad Higgins, Eric Richard Pardyjak

The flux of water vapor due to advection is measured using high-resolution Raman lidar that was orientated horizontally across a land-lake transition. At the same time, a full surface energy balance is performed to assess the impact of scalar advection on ...

American Meteorological Society2013

Coherent structures and the k(-1) spectral behaviour

Valentin Simeonov, Marc Parlange, Marc Calaf Bracons, Holly Jayne Oldroyd

l Here we present unique evidence of a k(-1) scaling behaviour in the atmospheric boundary layer and its connection to large scale coherent structures within the boundary layer. Wind lidar measurements were conducted above a lake under cold atmospheric con ...

Amer Inst Physics2013

Raman Lidar for Meteorological Observations, RALMO - Part 1: Instrument description

Bertrand Calpini, Hubert van den Bergh, Valentin Simeonov, Pablo Roberto Ristori, Todor Dinoev, Marc Parlange

A new Raman lidar for unattended, round-the-clock measurement of vertical water vapor profiles for operational use by the MeteoSwiss has been developed during the past years by the Swiss Federal Institute of Technology, Lausanne. The lidar uses narrow fiel ...

European Geosciences Union2013

A Raman lidar to measure water vapor in the atmospheric boundary layer

Hubert van den Bergh, Valentin Simeonov, Martin Froidevaux, Pablo Roberto Ristori, Marc Parlange, Ilya Serikov, Chad Higgins, Eric Richard Pardyjak

A new multi-telescope scanning Raman lidar designed to measure the water vapor mixing ratio in the atmospheric boundary layer for a complete diurnal cycle with high resolution spatial (1.25 m) and temporal (1 s) resolutions is presented. The high resolutio ...

Elsevier2013

Four-dimensional distribution of the 2010 Eyjafjallajokull volcanic cloud over Europe observed by EARLINET

Valentin Simeonov, Valentin Mitev, Frank Rüdiger Wagner, Ilya Serikov, Ivan Videnov Grigorov, Xiao Wang

The eruption of the Icelandic volcano Eyjafjallajokull in April-May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of ...

Copernicus GmbH2013

The Effect of Scale on the Applicability of Taylor’s Frozen Turbulence Hypothesis in the Atmospheric Boundary Layer

Valentin Simeonov, Martin Froidevaux, Nikki Vercauteren, Marc Parlange, Chad Higgins, Caitlin Ellen Barry

Taylor’s frozen turbulence hypothesis is the central assumption invoked in most experiments designed to investigate turbulence physics with time resolving sensors. It is also frequently used in theoretical discussions when linking Lagrangian to Eulerian fl ...

2012

Line-of-sight data transmission system based on Mid IR quantum cascade laser

Hubert van den Bergh, Valentin Simeonov

We report on an application of a pulsed distributed feedback quantum cascade laser (QCL) for an open path data transmission. A pulse QCL in the 1046 cm(-1) range (28.7 THz) is used as a carrier signal source. The QCL is modulated with 50 ns pulses at repet ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2008

Open-path ozone detection by quantum-cascade laser

Hubert van den Bergh, Valentin Simeonov, Martin Froidevaux

Springer-Verlag2006

Open path atmospheric spectroscopy using room temperature operated pulsed quantum cascade laser

Hubert van den Bergh, Valentin Simeonov

Elsevier2006