Search results for "atmosphere"

Source and Nature of Inhaled Atmospheric Dust from Trace Element Analyses of Human Bronchial Fluids

2011

International audience; Rapid volcanic eruptions quickly ejecting large amounts of dust provoke the accumulation of heavy metals in people living in surrounding areas. Analyses of bronchoalveolar lavage samples (BAL) collected from people exposed to the paroxysmal 2001 Etna eruption revealed a strong enrichment of many toxic heavy metals. Comparing the BAL to the dust composition of southeastern Sicily, we found that only V, Cr, Mn, Fe, Co, and U enrichment could be related to the volcanic event, whereas Ni, Cu, Cd, and Pb contents come from the dissolution of particles of anthropogenic origin. Furthermore, the nature of these inhaled anthropogenic particles was revealed by anomalous La and…

Du comptage ponctuel à l'affectation par simulation multi-agents : application à la circulation routière de la ville de Dijon

2014

A travers une démarche expérimentale de simulation de la circulation routière pour estimer les pollutions atmosphériques en milieu urbain, cette proposition questionne les opportunités qu'offre la simulation multi-agents pour intégrer des données d'observations du trafic routier au sein d'un système d'information géographique. Pour cela, la construction du modèle d'affectation s'est faite en deux étapes : une première, d'acquisition et de structuration des données de comptages et une seconde visant à interfacer ces données au sein d'une plateforme de simulation multi-agents pour en reproduire la variabilité intra journalière et la fréquentation routière.

Oxidation State and Local Structure of Chromium Ions in LaOCl

2021

This research is funded by the Latvian Council of Science, project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1-0335. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017- TeamingPhase2 under grant agreement No. 739508, project CAMART2.

Aerosol optical properties and direct radiative forcing based on measurements from the China Aerosol Remote Sensing Network (CARSNET) in eastern China

2018

Aerosol pollution in eastern China is an unfortunate consequence of the region's rapid economic and industrial growth. Here, sun photometer measurements from seven sites in the Yangtze River Delta (YRD) from 2011 to 2015 were used to characterize the climatology of aerosol microphysical and optical properties, calculate direct aerosol radiative forcing (DARF) and classify the aerosols based on size and absorption. Bimodal size distributions were found throughout the year, but larger volumes and effective radii of fine-mode particles occurred in June and September due to hygroscopic growth and/or cloud processing. Increases in the fine-mode particles in June and September caused AOD440 nm  &…

Unexpected vertical structure of the Saharan Air Layer and giant dust particles during AER-D

2018

The Saharan Air Layer (SAL) in the summertime eastern Atlantic is typically well mixed and 3–4 km deep, overlying the marine boundary layer (MBL). In this paper, we show experimental evidence that at times a very different structure can be observed. During the AERosol properties – Dust (AER-D) airborne campaign in August 2015, the typical structure described above was observed most of the time, and was associated with a moderate dust content yielding an aerosol optical depth (AOD) of 0.3–0.4 at 355 nm. In an intense event, however, an unprecedented vertical structure was observed close to the eastern boundary of the basin, displaying an uneven vertical distribution and a very …

Comparing different profiles to characterize the atmosphere for three MODIS TIR bands

2015

Abstract Accurate land surface temperature (LST) retrievals from sensors aboard orbiting satellites are dependent on the corresponding atmospheric correction, especially in the thermal infrared (TIR) spectral domain (8–14 μm). To remove the atmospheric effects from at-sensor measured radiance in the TIR range it is needed to characterize the atmosphere by means of three specific variables: the upwelling path and the hemispherical downwelling radiances plus the atmospheric transmissivity. Those variables can be derived from the previous knowledge of vertical atmospheric profiles of air temperature and relative humidity at different geo-potential heights and pressures. In this work, the above…

Precipitable water vapour content from ESR/SKYNET sun-sky radiometers: validation against GNSS/GPS and AERONET over three different sites in Europe

2018

The estimation of the precipitable water vapour content (W) with high temporal and spatial resolution is of great interest to both meteorological and climatological studies. Several methodologies based on remote sensing techniques have been recently developed in order to obtain accurate and frequent measurements of this atmospheric parameter. Among them, the relative low cost and easy deployment of sun–sky radiometers, or sun photometers, operating in several international networks, allowed the development of automatic estimations of W from these instruments with high temporal resolution. However, the great problem of this methodology is the estimation of the sun-photometric calibration par…

Coarse-mode mineral dust size distributions, composition and optical properties from AER-D aircraft measurements over the tropical eastern Atlantic

2018

Mineral dust is an important component of the climate system, affecting the radiation balance, cloud properties, biogeochemical cycles, regional circulation and precipitation, as well as having negative effects on aviation, solar energy generation and human health. Dust size and composition has an impact on all these processes. However, changes in dust size distribution and composition during transport, particularly for coarse particles, are poorly understood and poorly represented in climate models. Here we present new in situ airborne observations of dust in the Saharan Air Layer (SAL) and the marine boundary layer (MBL) at the beginning of its transatlantic transport pathway, from the AE…

Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

An Approach on the Hydrogen Absorption in Carbon Black after Gamma Irradiation

2013

In this work, different samples of an industrial carbon black are used to study the hydrogen intake from an over pres-surized atmosphere and its changes due to alteration of its level of crystallinity produced by ¿-irradiation. The monitor-ing of the hydrogen adsorption was made by means of thermogravimetric analysis and by measurements of some elec-trical parameters as the Seebeck coefficient. X-ray diffraction shows that the irradiation diminishes the level of crystal-line perfection. These results show interesting possibilities to use carbon black as cheap hydrogen absorbers.