Search results for "Mineral"

2018

Abstract. Volcanoes are a natural source of several reactive gases (e.g., sulfur and halogen containing species) and nonreactive gases (e.g., carbon dioxide) to the atmosphere. The relative abundance of carbon and sulfur in volcanic gas as well as the total sulfur dioxide emission rate from a volcanic vent are established parameters in current volcano-monitoring strategies, and they oftentimes allow insights into subsurface processes. However, chemical reactions involving halogens are thought to have local to regional impact on the atmospheric chemistry around passively degassing volcanoes. In this study we demonstrate the successful deployment of a multirotor UAV (quadcopter) system with c…

Reactive halogen chemistry in volcanic plumes

2007

[1] Bromine monoxide (BrO) and sulphur dioxide (SO2) abundances as a function of the distance from the source were measured by ground-based scattered light Multiaxis Differential Optical Absorption Spectroscopy (MAX-DOAS) in the volcanic plumes of Mt. Etna on Sicily, Italy, in August–October 2004 and May 2005 and Villarica in Chile in November 2004. BrO and SO2 spatial distributions in a cross section of Mt. Etna's plume were also determined by Imaging DOAS. We observed an increase in the BrO/SO2 ratio in the plume from below the detection limit near the vent to about 4.5 × 10−4 at 19 km (Mt. Etna) and to about 1.3 × 10−4 at 3 km (Villarica) distance, respectively. Additional attempts were …

Volcanic plume monitoring at Mount Etna by diffusive (passive) sampling

2004

[1] This paper reports the use of diffusive tubes in determining HF, HCl, and SO2 in the volcanic plume of Mount Etna in an attempt to highlight the potential of this method in studying volcanoes. In a first application a network of 18 diffusive tubes was installed on Etna's flanks, aimed at evaluating the atmospheric dispersion of the volcanic plume on a local scale. Results showed a monotonic decrease in volatile air concentrations with distance from the craters (HF from 0.15 to <0.003 μmol m−3, HCl from 2 to <0.01 μmol m−3, and SO2 from 11 to 0.04 μmol m−3), revealing the prevalently volcanic contribution. Matching of SO2/HCl and HCl/HF volatile ratios with contemporaneous measurements a…

Sources, size distribution, and downwind grounding of aerosols from Mount Etna

2006

The number concentrations and size distributions of aerosol particles >0.3 mm diameter were measured at the summit of Mount Etna and up to 10 km downwind from the degassing vents during July and August 2004. Aerosol number concentrations reached in excess of 9 106 L1 at summit vents, compared to 4–8 104 L1 in background air. Number concentrations of intermediate size particles were higher in emissions from the Northeast crater compared to other summit crater vents, and chemical composition measurements showed that Northeast crater aerosols contained a higher mineral cation content compared to those from Voragine or Bocca Nuova, attributed to Strombolian or gas puffing activity within the ve…

Application of aerosol optical properties to estimate aerosol type from ground-based remote sensing observation at urban area of northeastern China

2015

Abstract Aerosol optical properties were derived from ground-based sunphotometer observations between 2009-2013 at three urban sites of Shenyang, Anshan, Fushun in northeastern China. The annual means for extinction aerosol optical depths (EAOD) at 500 nm were 0.57±0.38, 0.52±0.35, and 0.41±0.31 at Shenyang, Anshan, Fushun, respectively. The corresponding annual means for the extinction Angstrom exponents (EAE) computed for the wavelengths of 440 and 870 nm were 0.86±0.32, 0.86±0.34 and 0.91±0.35, respectively, indicating that urban area of Northeast China were affected by both coarse and fine particles. Hygroscopic growth in summer and incursions of dust aerosols in spring were evidently r…

The tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations

2007

Abstract. Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent) volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily). Sulphur dioxide (SO2), hydrogen sulphide (H2S), hydrogen chlori…

Spectral surface albedo over Morocco and its impact on radiative forcing of Saharan dust

2011

In May–June 2006, airborne and ground-based solar (0.3–2.2 μm) and thermal infrared (4–42 μm) radiation measurements have been performed in Morocco within the Saharan Mineral Dust Experiment (SAMUM). Upwelling and downwelling solar irradiances have been measured using the Spectral Modular Airborne Radiation Measurement System (SMART)-Albedometer. With these data, the areal spectral surface albedo for typical surface types in southeastern Morocco was derived from airborne measurements for the first time. The results are compared to the surface albedo retrieved from collocated satellite measurements, and partly considerable deviations are observed. Using measured surface and atmospheric prope…

Size distribution, mass concentration, chemical and mineralogical composition and derived optical parameters of the boundary layer aerosol at Tinfou,…

2009

During the SAMUM 2006 field campaign in southern Morocco, physical and chemical properties of desert aerosols were measured. Mass concentrations ranging from 30 Ã�¼g m-3 for PM2.5 under desert background conditions up to 300,000 Ã�¼g m-3 for total suspended particles (TSP) during moderate dust storms were measured. TSP dust concentrations are correlated with the local wind speed, whereas PM10 and PM2.5 concentrations are determined by advection from distant sources. Size distributions were measured for particles between 20 nm and 500 Ã�¼m diameter (parameterizations are given). Two major regimes of the size spectrum can be distinguished. Smaller than 500 nm particle diameter, the distrib…

Saharan dust absorption and refractive index from aircraft-based observations during SAMUM 2006

2009

During the Saharan Mineral Dust Experiment (SAMUM) conducted in summer 2006 in southeast Morocco, the complex refractive index of desert dust was determined from airborne measurements of particle size distributions and aerosol absorption coefficients at three different wavelengths in the blue (467 nm), green (530 nm) and red (660 nm) spectral regions. The vertical structure of the dust layers was analysed by an airborne high spectral resolution lidar (HSRL). The origin of the investigated dust layers was estimated from trajectory analyses, combined with Meteosat 2nd Generation (MSG) scenes and wind field data analyses. The real part n of the dust refractive index was found almost constant w…

Mecanismos moleculares que median las acciones biológicas de los receptores de mineralocorticoides y glucocorticoides en la homeostasis cutánea

2017

Tesis doctoral, 198 páginas, figuras y tablas