A system for large volume aerosol sampling in the stratosphere using electrostatic precipitation     

Dr. Leonard R. Solon  Pedro Lilienfeld  Hugo J. DiGiovanni 《Meteorology and Atmospheric Physics》1968,17(2-3):251-289

Summary An instrumental system for securing aerosol samples in the stratosphere by electrostatic precipitation has been developed. The system is designed to be balloon borne to altitudes between 30 km and 45 km and to collect with high efficiency the aerosol content of the stratosphere at these altitudes. Volumetric sampling rates of one meter³ sec^–1 ambient air are obtained with the sampling configuration with collection efficiency in excess of 95 percent for particles between .01 microns (mmd) and 2 microns (mmd).Specially developed associated instrumentation for altitude and air flow measurement points to an important versatility in the application of gas discharges for low-pressure (or high altitude) altimetry and anemometry over a very wide range of air densities and tempertures.The theory, operation, and performance of the aerosol sampling system and associated subsytems are described. Certain new observations of low-density corona physics phenomena are reported and potential applications to other areas of research and technology are indicated.

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Zusammenfassung Es wurde ein Instrument entwickelt, mit dem man Aerosolproben aus der Stratosphäre durch elektrostatischen Niederschlag erhalten kann. Das System wird von einem Ballon in Höhen zwischen 30 und 45 km getragen und sammelt mit hoher Wirksamkeit Proben des Aerosolgehalts in diesen Höhen. Mit dem Instrument wird eine Sammelgeschwindigkeit von 1 m³/sek erreicht bei einer Sammelwirksamkeit von mehr als 95% für Partikel von Größen zwischen 0,01 und 2 Mikron.Besonders entwickelte angeschlossene Instrumente zur Messung der Höhe und der Luftströmungen zeigen die wesentliche Vielseitigkeit der Anwendung von Gasentladungen für die Höhenmessung und Windmessung bei niedrigem Druck (oder in großen Höhen) in einem großen Bereich der Luftdichte und der Temperatur.Es werden die Theorie, die Arbeitsweise und die Ausführung des Aerosolprobeninstrumentes und der angeschlossenen Hilfssysteme beschrieben. Es wird über einige neue Beobachtungen aus dem Bereich der Phänomene der Gasentladungen bei niedriger Dichte berichtet und neue mögliche Anwendungen in anderen Zweigen der Forschung und Technologie werden angegeben.

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Résumé On a construit un instrument au moyen duquel on peut obtenir des échantillons d'aérosole stratosphérique par précipitation électrostatique. Le système est emporté par un ballon à des altitudes de 30 à 45 km et rassemble avec efficacité des echantillons du contenu de l'aérosole à ces altitudes. Avec cet appareil, on obtient une vitesse de prise de 1 m³/sec avec une efficacité de plus de 95% pour les particules comprises entre 0,01 et 2 microns.Des appareils spéciaux annexes permettent de mesurer la hauteur et les courants d'air. Ils démontrent les possibilités multiples de l'utilisation de la décharge dans un gaz pour la mesure de l'altitude et des vents par pression très faible (ou à très haute altitude) dans un domaine étendu tant de la densité de l'air que de la température.On décrit dans ce mémoire la théorie, le mode de travail et l'exécution de cet instrument de prise d'échantillons d'aérosoles ainsi que des systèmes auxiliaires annexes. On rapporte sur quelques nouvelles observations faites dans le domaine des phénomènes connexes à la décharge dans un gaz par faible densité. On indique en outre de nouvelles possibilités d'utilisation du système dans d'autres branches de la recherche ou de la technologie.

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With 16 Figures

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This work has been supported by the Division of Biology and Medicine, U. S. Atomic Energy Commission, under contract at (30-1)-2363 with Del Electronics.  相似文献   

Analyzing ice dynamics using Sentinel-1 data at the Solheimajoküll Glacier,Iceland     

Diego Gómez  Pablo Salvador  Julia Sanz  Mikhail Urbazaev  José Luis Casanova 《地理信息系统科学与遥感》2020,57(6):813-829

ABSTRACT

The climate in southern Iceland has warmed over the last 70 years, resulting in accelerated glacier dynamics at the Solheimajoküll glacier. In this study, we compare glacier terminus locations from 1973 to 2018, to changes in climate across the study area, and we derive ice-surface velocities (2015–2018) from satellite remote-sensing imagery (Sentinel-1) using the offset-tracking method. There have been two regional temperature trends in the study period: cooling (1973–1979) and warming (1980–2018). Our results indicate a time lag of about 20 years between the onset of glacier retreat (?53 m/year since 2000) and the inception of the warming period. Seasonally, the velocity time series suggest acceleration during the summer melt season since 2016, whereas glacier velocities during accumulation months were constant. The highest velocities were observed at high elevations where the ice-surface slope is the steepest. We tested several scenarios to assess the hydrological time response to glacier accelerations, with the highest correlations being found between one and 30 days after the velocity estimates. Monthly correlation analyses indicated inter-annual and intra-annual variability in the glacier dynamics. Additionally, we investigate the linkage between glacier velocities and meltwater outflow parameters as they provide useful information about internal processes in the glacier. Velocity estimates positively correlate with water level and negatively correlate with water conductivity between April and August. There is also a disruption in the correlation trend between water conductivity and ice velocity in June, potentially due to a seasonal release of geothermal water.  相似文献   

Groundwater and volcanoes: examples from the Azores archipelago     

José?Virgílio?CruzEmail author 《Environmental Geology》2003,44(3):343-355

Groundwater at the Azores archipelago is a strategic resource for the freshwater supply. Freshwater, mineral and thermal water discharges occur in the archipelago, and especially at the Fogo and Furnas volcanoes (São Miguel). These discharges provide data for case studies of groundwater chemistry from volcanic monitoring due to the stable composition of the sampled waters. The mineral and thermal discharges are mainly of sodium bicarbonate types and present a large range of temperatures, from cold springs to waters at about 90 °C. Some boiling discharges have a sulfate-dominated composition, suggesting a steam-heating mechanism. Geochemical studies on these mineral and thermal waters began in the 19th century. Data gathered since these earlier studies provide a baseline for pH, temperature, CO₂ and major-element composition. Weekly measurements of pH and temperature also denote a rather stable behavior.  相似文献   

A paleoenvironmental reconstruction of Laguna Babícora, Chihuahua, Mexico based on ostracode paleoecology and trace element shell chemistry     

Manuel R. Palacios-Fest  Ana Luisa Carreño  José R. Ortega-Ramírez  Guillermo Alvarado-Valdéz 《Journal of Paleolimnology》2002,27(2):185-206

Paleoecology of Laguna Babícora, Chihuahua, Mexico was reconstructed using ostracode faunal assemblages and shell chemistry. The paleolimnological record is used to show the magnitude of paleoclimatic changes in the area from 25,000 years to the present.Faunal assemblages consist of four species of the genus Limnocythere: L. sappaensis, L. ceriotuberosa, L. bradburyi and L. platyforma, all associated with Candona caudata, Candona patzcuaro and Cypridopsis vidua. A paleosalinity index developed from these assemblages indicates that the lake's salinity fluctuated frequently from oligo- to meso-haline conditions during the last 25,000 years. This pattern and low salinity range are in good agreement with modern TDS (here used as an indicator of salinity) values recorded from 26 wells and one spring from the area (258–975 mg l^–1). To estimate paleotemperature we examined the trace element content (Mg/Ca ratios) from individual valves of L. ceriotuberosa and L. platyforma, the two species most commonly recorded in Laguna Babícora.Shell Mg/Ca ratios of 204 specimens of these two species were used to estimate water temperature (Mg/Ca) by means of experimental standard coefficients. Our data show that paleowater temperature ranged from 5.6–21.3 °C (with 2 values ranging from 0.2–4.8 °C), which suggest a close correlation with atmospheric temperatures around the lake. These results are in good agreement with a modern mean winter temperature (3.5 °C) and mean summer temperature (20 °C) recorded in the area between 1970 and 1980.  相似文献   

Diffuse Emission of CO2 from Showa-Shinzan, Hokkaido, Japan: A Sign of Volcanic Dome Degassing   总被引：1，自引：0，他引：1  

Pedro A. Hernández  Kenji Notsu  Hiromu Okada  Toshiya Mori  Masanori Sato  Francisco Barahona  Nemesio M. Pérez 《Pure and Applied Geophysics》2006,163(4):869-881

Two soil CO₂ efflux surveys were carried out in September 1999 and June 2002 to study the spatial distribution of diffuse CO₂ degassing and estimate the total CO₂ output from Showa-Shinzan volcanic dome, Japan. Seventy-six and 81 measurements of CO₂ efflux were performed in 1999 and 2002, respectively, covering most of Showa-Shinzan volcano. Soil CO₂ efflux data showed a wide range of values up to 552 g m^-2 d^-1. Carbon isotope signatures of the soil CO₂ ranged from -0.9‰ to -30.9‰, suggesting a mixing between different carbon reservoirs. Most of the study area showed CO₂ efflux background values during the 1999 and 2002 surveys (B = 8.2 and 4.4 g m^-2 d^-1, respectively). The spatial distribution of CO₂ efflux anomalies for both surveys showed a good correlation with the soil temperature, indicating a similar origin for the extensive soil degassing generated by condensation processes and fluids discharged by the fumarolic system of Showa-Shinzan. The total diffuse CO₂ output of Showa-Shinzan was estimated to be about 14.0–15.6 t d^-1 of CO₂ for an area of 0.53 km².  相似文献   

Sources of dissolved REE in mountainous streams draining granitic rocks, Sierras Pampeanas (Córdoba, Argentina)   总被引：1，自引：0，他引：1  

M. Gabriela García  Karina L. Lecomte  Andrea I. Pasquini  Stella M. Formica  Pedro J. Depetris 《Geochimica et cosmochimica acta》2007,71(22):5355-5368

Stream waters draining granitic terrains from the highest part (850 to 2200 m a.s.l.) of Sierras Pampeanas (Córdoba, Argentina, ∼32°S, ∼65°W) were sampled in order to define sources and distribution of dissolved rare earth elements (REE), and to describe the geochemical processes that govern their mobility. The contribution of the regional granite to the dissolved REE pool in stream water is limited due to the physical conditions predominating in the area (i.e., steep slopes and semiarid climate). Therefore, precipitation is considered a seasonally significant source controlling REE concentration in stream water. Dissolved REE concentrations are inversely correlated with monthly precipitation and rainfall frequency. During the rainy season (i.e., the austral summer) REE concentrations in stream water are lower than during the dry season (i.e., austral winter). Such low concentrations reflect the balance between the REE input from precipitation and their removal by adsorption. In contrast, during the dry season, the longer residence time of water within fractures and colluvium determines an increased REE concentration in the base flow. Lower pH values also contribute to raise REE concentration through desorption from mineral surfaces.  相似文献   

Post-collisional transition from calc-alkaline to alkaline magmatism during transcurrent deformation in the southernmost Dom Feliciano Belt (Braziliano–Pan-African, Uruguay)     

Pedro Oyhantabal  Siegfried Siegesmund  Klaus Wemmer  Robert Frei  Paul Layer 《Lithos》2007,98(1-4):141-159

In the southernmost Dom Feliciano Belt of Uruguay, highly fractionated calc-alkaline granites, mildly alkaline granites, shoshonitic volcanics, and peralkaline intrusions and volcanics are spatially and temporal associated with the evolution of shear zones. Four representative magmatic unites of this diverse association were petrographic and geochemically investigated: the Solís de Mataojo Complex, a medium to high K2O calc-alkaline granite with signature typical of mature continental arcs and post-collisional settings; the Maldonado granite, highly fractionated calc-alkaline to alkaline, with characteristics that are transitional between both types of series; the Pan de Azúcar Pluton, with characteristics typical of post-collisional alkaline granites and the Las Flores shoshonitic basalts.

Geochemistry and geotectonic setting point out that slab breakoff was most likely the mechanism associated with the generation of high-K calc-alkaline magmas (Solís de Mataojo and Maldonado) shortly after collision. Extension associated to the formation of molassic basins and emplacement of dolerites and basalt flows with shoshonitic affinity (Las Flores) 15and finally a shift to magmas with alkaline signatures (Pan de Azúcar) simultaneous with a second transpressional phase were probably linked with lithospheric thinning through delamination. This evolution took place between 615 and 575 Ma, according to available data. Contrary to previous proposals, which considered this magmatism to represent the root of a continental magmatic arc, a post-collisional environment, transitional from orogenic to anorogenic, during transcurrent deformation is proposed.  相似文献   

Nutrient dynamics in Mediterranean temporary streams: A case study in Pardiela catchment (Degebe River, Portugal)   总被引：1，自引：0，他引：1  

Ana Isabel Lilleb  Manuela Morais  Pedro Guilherme  Rita Fonseca  Antnio Serafim  Ramiro Neves 《Limnologica》2007,37(4):337-348

Most of the streams in the Mediterranean region are temporary, following predictable seasonal of flooding and drying, with a transition from lotic conditions to shallow lentic conditions. The goal of our study was to assess the nitrogen and phosphorus dynamics in channel-bed processes of temporary streams between floods. Results show that, during winter, temperatures ranged between 9.5 and 11.2 °C and oxygen concentration ranged from 8.0 to 9.5 mg L⁻¹, whereas, during summer, temperatures varied between 21.2 and 26.8 °C and oxygen between 1.2 and 5.3 mg L⁻¹, with oxygen depletion in the pools during the night. The nitrate concentrations were far more abundant during winter (February), while ammonium concentration increased after stream fragmentation into pools (especially in July when oxygen depletion conditions favoured ammonification). Results on sediment profiles showed that the most active sediment layers for NH₄-N are the top 2–3 cm, corresponding to the sediment depositional sites of the stream. Phosphate concentrations had larger variability, yet concentrations decreased from winter to spring and increased again in summer, when the shallow water pools were formed. Sediment profiles at the sediment depositional sites showed that PO₄-P was more dynamic in the first 6 cm.

In Mediterranean temporary streams, nutrient dynamics vary seasonally, as the system transits from lotic conditions to shallow lentic conditions, evidencing the regeneration of nutrients from organic and inorganic matter during the flow cessation period.  相似文献   

Vulnerability assessment in a volcanic risk evaluation in Central Mexico through a multi-criteria-GIS approach   总被引：1，自引：1，他引：1  

José Fernando Aceves-Quesada  Jesús Díaz-Salgado  Jorge López-Blanco 《Natural Hazards》2007,40(2):339-356

The Valley of Toluca is a major industrial and agricultural area in Central Mexico, especially the City of Toluca, the capital of The State of Mexico. The Nevado de Toluca volcano is located to the southwest of The Toluca Basin. Results obtained from the vulnerability assessment phase of the study area (5,040 km² and 42 municipalities) are presented here as a part of a comprehensive volcanic risk assessment of The Toluca Basin. Information has been gathered and processed at a municipal level including thematic maps at 1:250,000 scale. A database has been built, classified and analyzed within a GIS environment; additionally, a Multi-Criteria Evaluation (MCE) approach was applied as an aid for the decision-making process. Cartographic results were five vulnerability maps: (1) Total Population, (2) Land Use/Cover, (3) Infrastructure, (4) Economic Units and (5) Total Vulnerability. Our main results suggest that the Toluca and Tianguistenco urban and industrial areas, to the north and northeast of The Valley of Toluca, are the most vulnerable areas, for their high concentration of population, infrastructure, economic activity, and exposure to volcanic events.  相似文献   

Occurrence and Resistance of Pathogenic Bacteria Along the Tietê River Downstream of São Paulo in Brazil     

Wolf-Rainer Abraham  Alexandre José Macedo  Luiz Humberto Gomes  Flavio C. A. Tavares 《洁净——土壤、空气、水》2007,35(4):339-347

The load of pathogenic bacteria, their fate and their dangerousness in the Tietê River were assessed along 100 km starting from the city of São Paulo, Brazil. The data were compared with those from two German rivers. High loads of pathogens were found in the Tietê River near the city of São Paulo (Escherichia coli O157:H7, Shigella flexneri, and Shigella boydii), which were absent 30 km downstream of São Paulo. The antibiotic resistances observed in the Tietê river were rather low and decreased after the major input in São Paulo to significantly lower levels about 30 km downstream. While the Brazilian isolates were more susceptible for ampicillin than the German ones, the reverse was observed for gentamycin. For optimal control of infections in humans critical areas where these bacteria survived longer and their elimination mechanisms should be identified as well as the extent and the origin of antibiotic resistance should be determined.  相似文献