Publications by Bertrand Calpini

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From lidar signals detected with a shot/shot differential absorption lidar instrument tuned for tropospheric O3 measurements and recording each individual return, histograms of their sampled values for each channel of their digitizers were reconstructed. Anal. of their shape permits correction of measurements for exptl. biases. In particular, a neg. correlation was obsd. between the histogram skew and the intensity of backscattered light. The skew comes from a tail at high sampled values, interpreted as due

This paper concerns an evaluation of ozone (O-3) and planetary boundary layer (PBL) dynamics over the complex topography of the Grenoble region through a combination of measurements and mesoscale model (METPHOMOD) predictions for three days, during July 1999. The measurements of O-3 and PBL structure were obtained with a Differential Absorption Lidar ( DIAL) system, situated 20 km south of Grenoble at Vif (310m ASL). The combined lidar observations and model calculations are in good agreement with atmospher

The Grenoble metropolitan area located in the French Alps with more than 400 thousand inhabitants suffers from periods of high ozone (O3) concentrations in summertime. Grenoble is moreover located in the Y shaped convergence of three deep valleys with surrounding mountains up to 3 000 m above sea level (asl) leading to a very complex wind pattern. During summer 1999, a major field campaign GRENOble PHOTochemistry (GRENOPHOT) involving standard ground based stations, LIDAR, aircraft, DOAS, microwave windprof

A new lidar instrument was developed to measure tropospheric ozone and water vapor at low altitude. The lidar uses Raman scattering of an UV beam from atm. nitrogen, oxygen, and water vapor to retrieve ozone and water-vapor vertical profiles. By numerical simulation the authors study the sensitivity of the method to both atm. and device perturbations. The aerosol optical effect in the planetary boundary layer, ozone interference in water-vapor retrieval, statistical error, optical cross talk between Raman-s

The Grenoble metropolitan area located in the French Alps with more than 400 thousand inhabitants suffers from periods of high ozone (O3) concns. in summertime. Grenoble is moreover located in the Y shaped convergence of three deep valleys with surrounding mountains up to 3,000 m above sea level (asl) leading to a very complex wind pattern. During summer 1999, a major field campaign GRENOble PHOTochem. (GRENOPHOT) involving std. ground based stations, LIDAR, aircraft, DOAS, microwave windprofilers was carri

The Jungfraujoch Research Station (46.55 degrees N, 7.98 degrees E, 3580 m above sea level) for decades has contributed in a significant manner to the systematic observation of the Earth's atmosphere both with in situ measurements and with trace gas column detection. We report on the development of a lidar system that improves the measurement potential of highly resolved atmospheric parameters in both time and space, with the goal of achieving long-term monitoring of atmospheric aerosol optical properties a

Numerical simulations compared with field measurements are used to explain the effect of sea breezes on photochemical smog episodes in Athens during the Mediterranean Campaign of Photochemical Tracers on 12-14 September 1994. The numerical simulations, performed using a nonhydrostatic vorticity mesoscale model coupled to the Lurmann-Carter-Coyner photochemical module, are compared with ground-based lidar and aircraft measurements. The current analysis shows that the three selected days include the two main

Single-pass Raman cells pumped by either a quadrupled Nd:YAG (266-nm) laser or a KrF excimer laser are studied. The Raman-active gases comprise H2, D2, or CH4, as well as a mixt. of them, with the addn. of He, Ne, or Ar. A parametric study, in which the Stokes conversion efficiency and the beam quality (M2) were measured, was made. The first Stokes efficiency increases and all the Stokes thresholds decrease with an increase in the lens focal length or the M2 parameter of the pump beam. The quality of the St

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 ...

We report direct absorption spectroscopic detection of ozone at ambient pressure with a pulsed, DFB quantum-cascade laser (QCL) tuned within 1044-1050 cm(-1) by temperature scanning. Wavelength calibration curves were derived from FTIR and CO2 spectra and interpreted with respect to the heat transfer from the heterostructure to the sink. The laser linewidth (similar to0.13 cm(-1) FWHM) was found to decrease with temperature, probably as a result of operation at constant current. Spurious spectral features d

Hydroxyl radicals dominate daytime tropospheric chem., responsible for reactive removal of most trace gases (e.g., volatile org. compds.[VOC]), and is an active participant in the NO and NO2 cycle. Pump-and-probe LIDAR was used to examine the OH- chem. in the planetary boundary layer. This method consists of a high OH- concn. prodn. by a first laser beam (pump), including a flash photolysis of O3: O3 + hv (256 nm) -> O(1D) + O2, and the reaction, O(1D) + H2O -> 2OH. Its relaxation is followed by measuring t

The deposition of copper by low pressure chem. vapor deposition (CVD) from Cu bis-hexafluoroacetylacetonate is monitored in real time and in situ by the measurement of the optical reflectivity and elec. resistance of the growing metal film. Changes of the deposit morphol. during growth were analyzed by interrupting the CVD process at different stages and observing the samples by transmission electron microscopy. Pure copper is deposited at 400 Deg and 1 mbar total reactor pressure of helium, precursor, and

Water vapour has been measured from the International Scientific Station Jungfraujoch (ISSJ, 47° N, 7° E, 3580 in above sea level) during the winters of 1999/2000 and 2000/2001 by microwave radiometry and Raman lidar. The abundance of atmospheric water vapour between the planetary boundary layer and the upper stratosphere varies over more than three orders of magnitude. The currently used measurement techniques are only suited to determine the abundance of water vapour in different atmospheric regimes. None

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 ...

The scope of this paper is to provide an exptl. and modeling contribution on the role of suspended lower tropospheric particles to the UV spectral irradiance reaching the ground in urban environments. The UV spectral irradiance was measured with a UV spectrophotometer, while the aerosol data were obtained simultaneously by a lidar system operating in the 300 nm spectral region. Both UV and lidar instruments were operated inside the Athens basin during various air pollution and meterol. conditions, in the fr

Preliminary work confirmed the important contribution of regional scale processes on pollutant concns. obsd. at local scales. For Grenoble, France, the model domain for simulations discussed, was selected considering the topog., urban area distribution, boundary conditions, and possible constraints in terms of computing time. The nesting technique used involved calcns. over a larger domain which contained the smaller domain. Two of the most important components of these models are the chem. mechanism and tr

A new lidar for the measurement of tropospheric ozone is proposed, based on the differential analysis of the Raman backscattered signals on nitrogen and oxygen, which is far less sensitive to the aerosols than the classical DIAL system. Using a third Raman channel, the system is able to measure the water vapor mixing ratio simultaneously. The transmitting section of the instrument is composed of a single wavelength at 266 nm, generated by a quadrupled Nd:YAG laser, while the receiving section is the combina

Measurements of local air pollution and road traffic were taken during a period of one month before and after the opening of a road tunnel to the public in nearby Sachseln, a small city located in a rural region (Obwald) at the center of Switzerland. Two 5-day periods of time (before and after the tunnel opening) of equivalent weather and road traffic features were selected for assessing the tunnel impact on air quality. Despite the road traffic across Sachseln dropped by about 50% after the tunnel opening,

Recent research works show that wastewater treatment plants may contribute significantly to the total emission of volatile org. compds. (VOCs) in urban areas. In order to investigate this contribution, a measurement campaign was carried out during Sept., 1999, in the Lausanne, Switzerland, area. The concns. of monocyclic arom. hydrocarbons (MAHs) over a wastewater treatment plant at Lausanne were monitored by differential optical absorption spectroscopy (DOAS) and gas chromatog. with a flame ionization dete

A computer simulation of some chem. scenarios are presented to obtain preliminary information on what can be learned from pump-and-probe lidar expts., i.e., in situ laser flash photolysis in the troposphere. The decay of the OH concn. following the flash photolysis by different spatially resolved techniques is done under different conditions where the significant chem. and meteorol. parameters were sep. measured, so that model calcs. can be compared with time-dependent OH concns. The scenarios, within the l

Bertrand Calpini

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Correction scheme for experimental biases in differential absorption lidar tropospheric ozone measurements based on the analysis of shot per shot data samples

An investigation of ozone and planetary boundary layer dynamics over the complex topography of Grenoble combining measurements and modeling

Étude d'un épisode photochimique à l'aide d'un modèle méso-échelle et de mesures intensives sur la région de Grenoble

Ozone and water-vapor measurements by Raman lidar in the planetary boundary layer: Error sources and field measurements

Study of a photochemical episode over the Grenoble area using a mesoscale model and intensive measurements

Development of a multiwavelength aerosol and water-vapor lidar at the Jungfraujoch Alpine Station (3580 m above sea level) in Switzerland

Effect of sea breeze on air pollution in the greater Athens area. Part I: Numerical simulations and field observations

Experimental investigation of high-power single-pass Raman shifters in the ultraviolet with Nd:YAG and KrF lasers

Raman lidar in operational meteorology

Ozone detection by differential absorption spectroscopy at ambient pressure with a 9.6 mu m pulsed quantum-cascade laser

In-situ OH kinetics study providing an indicator for ozone formation limitation

Copper film growth by chemical vapor deposition. Electrical and optical measurements in real time, and studies of morphology

Ground-based water vapour soundings by microwave radiometry and Raman lidar on Jungfraujoch (Swiss Alps)

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

Role of urban and suburban aerosols on solar UV radiation over Athens, Greece

Measurement campaign and numerical modelling in the complex topography of the Grenoble area (France) during summer '99

Raman DIAL measurement of ozone and water vapor in the lower troposphere

Evidence of primary air pollutant reduction and photochemical pollution enhancement after opening a road tunnel to the public

Investigation of the emission of monocyclic aromatic hydrocarbons from a wastewater treatment plant at Lausanne (Switzerland) by differential optical absorption spectroscopy (DOAS)

Pump-and-probe lidar for in-situ probing of atmospheric chemistry