Tons Of Dust Research Articles

황사 발생 기간 낙하먼지에 포함된 미생물의 분포 및 특성

황사는 중국과 몽골의 사막지역과 중국 황하 중 상류의 황토지대에서 바람에 의해 대기 중에 부유한 미세먼지가 상층 바람을 타고 멀리까지 날아가는 기상 현상을 말한다. 황사 먼지는 bioaerosol을 포함하며 미생물의 운반체로 작용할 수 있다. 따라서 본 연구에서는 황사 발생 기간과 황사가 없는 기간 동안 각각 포집한 낙하먼지에서 미생물의 농도와 종 조성을 비교하고자 하였다. 2008년 2월부터 4월까지 울산 지역의 한 지점에서 직경 200 mm의 강수량계를 사용하여 낙하먼지를 포집하였으며, 조사 기간 동안 울산 지역에서 황사 현상은 3월 2일과 3일에 걸쳐 한번 발생하였다. 낙하먼지에 포함된 세균의 농도는, 황사 기간 동안 포집한 시료에서 황사가 없는 기간의 시료에 비해 크게 높았다. 하지만, 낙하먼지의 진균 농도는 비 황사 기간에 비해 황사 기간 동안 유의성 있게 증가하지 않았으며, 조사 기간 동안 세균에 비해 상대적으로 일정한 수준을 유지하였다. 낙하먼지 시료로부터 분리한 45개 세균의 16S rRNA 유전자 염기 서열을 분석하였으며, 이들 세균은 Bacillus 속의 B. amyloliquefaciens, B. aryabhattai, B. atrophaeus, B. licheniformis, B. megaterium, B. methylotrophicus, B. pumilus, B. sonorensis, B. subtlis, B. vallismortis와 Staphylococcus 속의 S. epidermidis, S. succinus로 확인되었다. 진균의 경우 Mucor 속, Alternaria 속, Cladosporium 속, Aspergillus 속 등을 황사 기간 및 비 황사 기간의 시료에서 모두 확인할 수 있었다. Bacillus 속과 같은 내생포자를 형성하는 세균이 진균(포자)에 비해 황사 먼지에의 부착 및 이동과 더 연관이 있는 것으로 보인다. Asian dust storms originating in the arid desert of China and Mongolia usually occur from late winter through spring, and more than one million tons of dust per year is transported to the Korean Peninsula by the prevalent westerly winds. We supposed that these dust particles could include bioaerosols and act as carriers of microorganisms. In order to clarify the dynamics of microorganisms moving with these particles, the concentration and composition of microorganisms associated with settled particles were compared between samples collected during Asian dust events and those under non-dust periods. From February to April 2008, settled dust particles were collected at one location in Ulsan using rainfall meter of 200 mm diameter. During this period, there was one Asian dust event in Ulsan. The bacterial concentrations were higher in samples collected during Asian dust event than those under non-dust period, whereas fungal concentrations were rather similar regardless of the Asian dust event. We analyzed 16S rRNA gene sequences of 45 bacterial isolates obtained from the settled particle samples. These isolates belonged to either genus Bacillus or genus Streptococcus and were tentatively identified as B. amyloliquefaciens, B. aryabhattai, B. atrophaeus, B. licheniformis, B. megaterium, B. methylotrophicus, B. pumilus, B. sonorensis, B. subtlis, B. vallismortis, S. epidermidis, and S. succinus. In cases of fungal isolates, genera such as Mucor, Alternaria, Cladosporium, and Aspergillus were tentatively identified from samples collected at both Asian dust and non-Asian dust periods. It appears that endospore-forming bacteria such as Bacillus sp. rather than fungal spores are more likely to be associated with Asian dust particles.

Chemical contamination assessment of the Hudson–Raritan Estuary as a result of the attacks on the World Trade Center: Analysis of trace elements

The attack on the World Trade Center (WTC) resulted in the destruction of buildings, and the release of tons of dust and debris into the environment. As part of the effort to characterize the environmental impact of the WTC collapse, Mussel Watch Program trace element measurements from the Hudson–Raritan Estuary (HRE) were assessed for the years before (1986–2001) and after (2001–2005) the attack. Trace element measurements in the HRE were significantly higher than Mussel Watch measurements taken elsewhere in the Nation. Post-attack trace element measurements were not significantly different from pre-attack measurements. The impacts of WTC collapse may have been obscured by high ambient levels of trace elements in the HRE.

Dust: The Inside Story of Its Role in the September 11th Aftermath By Paul J. Lioy . New York: Rowman & Littlefield, 2010. 245 pp. ISBN: 978-1-4422-0148-4, $34.95

Dust: The Inside Story of Its Role in the September 11th Aftermath <i>By Paul J. Lioy</i> . New York: Rowman &amp; Littlefield, 2010. 245 pp. ISBN: 978-1-4422-0148-4, $34.95

A new-generation sand and dust storm forecasting system GRAPES_CUACE/Dust: Model development, verification and numerical simulation

Based on the new-generation Global/Regional Assimilation and PrEdiction System (GRAPES) developed by the Numerical Prediction Research Center, China Meteorological Administration and the Chinese Unified Atmospheric Chemistry Environment for Dust Atmospheric Chemistry Module (CUACE/Dust) developed by the Centre for Atmosphere Watch and Services (CAWAS) of the Chinese Academy of Meteorological Sciences (CAMS), the China sand and dust storm forecasting system GRAPES/CUACE-Dust model has been established. The latest data of land desertification, optical properties of China sand and dust aerosols, daily soil moisture and snow cover over China main land was introduced in this system. The system showed good performance in mass conservation. The comparisons of real-time prediction outputs with surface observations and aerosol indices derived from TOMS ozone spectrophotometers (TOMS AI) indicate that the model can predict the outbreak, development, transport and depletion processes of sand and dust storms accurately over China and the East Asian region. The system makes real-time quantitative prediction of a series of elements including sand and dust injection from the surface, dry and wet deposition amount, dust concentration and optical depth. We selected 7 major dust storms occurring in April 2006 and analyzed the spatiotemporal distribution patterns of dust emission, dry and wet deposition and atmospheric load in this paper. The results showed that about 225 million tons of dust were emitted into the atmosphere from the deserts over east Asia in that month. The 3 major sand and dust sources were just as the following: The deserts in northern Inner Mongolia and the boundary area around China-Mongolia were the first dust sources with a contribution of 153 million tons accounting for 68% of the total emission. The Taklimakan Desert ranked second and contributed approximately 40 million tons accounting for 17% of the dust emission. The Onqin Daga Sandland emitted about 15 million tons or 7% of the total emission. The contributions from other deserts, sandy lands and abandoned farmlands were about only 8% of the total dust emission. The total deposition over the East Asian region in April 2006 was 136 million tons. The regional distribution of dust deposition showed that the 3 major sources were also the major deposition areas. The deposition amount in the 3 major sources accounted for 78% of the total with about 135 million tons falling back to the source regions. The secondary deposition area was the China mainland downriver, where more than 2 million tons deposited accounting for 16% of the total deposition. The deposition over the region east of 120°E including China off-shore regions, Korean Peninsula, Japan and the West Pacific took only 6% of the total deposition, which was about 850000 tons. The analysis on dry and wet deposition showed that dry deposition dominated in the process, accounting for 94% of the total sand and dust depositions in the period and wet deposition only was around for 6%, since it was generally dry with less rainfall over northern China in April.

リサイクリング・プロセスと操業 曹鉄メタル（株）における製鋼煙灰処理

Sotetsu Metal Co., Ltd. was established in 1974 and started operation of Waelz kiln plant for treatment of EAF dust. In 1996, Sotetsu plant installed two Waelz kilns in series. At present, Sotetsu plant treats 70,000 tons of dust and produces 24,000 tons of crude zinc oxide and then 18,000 tons of high grade zinc oxide per annum. The chemical composition of the high grade zinc oxide is 78wt%Zn, 1.1wt%Fe, 0.02wt%Pd,

Asian dustfall in the St. Elias Mountains, Yukon, Canada

In April 2001, a major atmospheric dustfall event occurred in the St. Elias Mountains, Yukon Territory, Canada. Field samples were collected and analyzed for particle size, mineralogy, chemical composition and Sr, Nd and Pb isotopes. Dusts found above ∼3000 m had their source in the Gobi desert region of northern China and Inner Mongolia, and were transported to the Yukon following a series of major dust storms that took place in early April. Dusts found below 3000 m had local (Yukon) or mixed source(s). The Asian dusts had a modal volume diameter of ∼4 μm typical of far-traveled mineral aerosols. However larger (>10 μm) particles were also found at ∼5000 m, suggesting a very rapid trans-Pacific transport in the mid-troposphere. We estimate that the April 2001 event deposited from 5500 to 6335 tons of dust over an area of 21,000 km 2 in the southwestern Yukon, most of which probably fell within a week. Our findings are consistent with instrumental observations and model simulations of the April 2001 event. While the dust cloud was reportedly mixed with volatile pollutants from Asia, we found no evidence of metal pollution associated with the dustfall in the Yukon. Our findings contribute to clarify the dynamics and the geochemical impact of Asian dust long-range transport events, and to better estimate eolian fluxes of dustborne elements (e.g., Fe) to the Ocean associated with such events. They may also assist in identifying past Asian dust events in ice cores drilled from the St. Elias Mountains icefields, to develop a long-term record of their frequency, magnitude and source(s).

The asteroid and comet impact hazard: risk assessment and mitigation options

The impact of extraterrestrial matter onto Earth is a continuous process. On average, some 50,000 tons of dust are delivered to our planet every year. While objects smaller than about 30 m mainly disintegrate in the Earth's atmosphere, larger ones can penetrate through it and cause damage on the ground. When an object of hundreds of meters in diameter impacts an ocean, a tsunami is created that can devastate coastal cities. Further, if a km-sized object hit the Earth it would cause a global catastrophe due to the transport of enormous amounts of dust and vapour into the atmosphere resulting in a change in the Earth's climate. This article gives an overview of the near-Earth asteroid and comet (near-Earth object-NEO) impact hazard and the NEO search programmes which are gathering important data on these objects. It also points out options for impact hazard mitigation by using deflection systems. It further discusses the critical constraints for NEO deflection strategies and systems as well as mitigation and evacuation costs and benefits. Recommendations are given for future activities to solve the NEO impact hazard problem.

Linking the scales of observation, process, and modeling of dust emissions

Each year, approximately four billion tons of dust are mobilized from dry landscapes and remain in the atmosphere from hours to weeks before being deposited. These large atmospheric dust loadings directly affect atmospheric dynamics and global climate [Intergovernmental Panel on Climate Change, 2001], human health [Plumlee and Ziegler, 2003], and soil fertility, and also influence ecosystem dynamics in ocean basins.Although some progress has been made in quantifying feedbacks (see Figure 1 on the Eos Electronic Supplement at http:www. agu. org/eos_elec/000931e.html) in the atmospheric dust cycle, the critical factors controlling the entrainment and transport of dust at differing spatial and temporal scales remain poorly quantified.

Reciclagem da poeira e lama geradas na fabricação de aço inoxidável

Foi realizado, em escala de laboratório, um estudo da recuperação dos metais cromo e níquel, contidos em resíduos gerados no processo de fabricação de aço inoxidável, utilizando-se altas temperaturas (1570, 1600 e 1635ºC). A maioria desses tipos de resíduos, principalmente a lama, ainda é disposta em aterros ou estocada. Nesse trabalho foram utilizados dois tipos de resíduo com alto teor de cromo, uma poeira (RESA) e o uma lama (RESB). A primeira etapa do estudo, fundamental para o estudo visando à reciclagem dos resíduos, foi a caracterização utilizando as seguintes técnicas: análise química, distribuição granulométrica (MALVERN), difração de raios X, microscopia eletrônica de varredura (MEV) e análise de micro-regiões (EDS). A segunda etapa envolveu a aglomeração dos resíduos caracterizados e outros reagentes, antes de serem introduzidos no aço líquido, utilizando-se uma briquetadora manual. Foram fabricados três briquetes com cada um dos resíduos. A terceira etapa da pesquisa foi a adição dos briquetes de resíduos no aço líquido e retirada periódica de amostras do banho para avaliação da incorporação do cromo contido nos resíduos no aço. O tipo de aço utilizado foi o aço carbono ASTM 1020. Os experimentos foram realizados em um equipamento em escala laboratorial, composto de um forno vertical que pode atingir até 1700ºC e seu controlador. O forno possui uma região de temperatura uniforme de cerca de 13 cm e, nessa região, o cadinho de alumina contendo aço é colocado. Esse equipamento foi construído para o estudo das reações envolvidas quando se adicionam resíduos em aço líquido. A atmosfera interna do aparato pode ser controlada. Após a introdução do briquete no aço líquido e sua fusão foram retiradas, periodicamente, amostras do banho em intervalos de tempo de três em três minutos para análise dos teores de vários elementos, principalmente o cromo, o níquel e o silício, principalmente. Cada experimento durou até 30 minutos. Os resultados mostraram que é possível, recuperar os metais contidos nos resíduos através desse processo, produzindo uma liga à base de ferro, cromo e níquel. O novo resíduo gerado (escória) contém uma menor quantidade de metais, em relação ao resíduo inicial. Altos valores de recuperação de metais dos resíduos foram atingidos. Para o níquel, a recuperação foi total, tanto para a poeira, quanto para a lama e para o cromo, os teores atingidos foram próximos a 100%.

CHEMICAL ANALYSIS OF A DISASTER

WITH THE COLLAPSE OF NEW YORK CITY'S TWO World Trade Center (WTC) towers on Sept. 11,2001, more than 1 million tons of dust enveloped lower Manhattan. And fires that lingered at ground zero until December created a plume of smoke initially detectable from space. Aerosols that could be seen and smelled were inescapable during and long after the attack on the World Trade Center. But aerosols are also transient. Were it not for a handful of scientific groups that quickly mobilized, usually donating time and money to collect ambient air data and dust samples near ground zero, little would now be known about the WTC aerosols. Many of the scientists who tested and analyzed the WTC air gathered for a symposium at the recent American Chemical Society national meeting in Newark City to discuss their results. They described the composition of the fallout dust, estimated where it came from, and proposed how its properties led ...

Retrieval of mass and sizes of particles in sandstorms using two MODIS IR bands: A case study of April 7, 2001 sandstorm in China

A thermal infrared remote sensing retrieval method developed by Wen and Rose [1994], which retrieves particle sizes, optical depth, and total masses of silicate particles in the volcanic cloud, was applied to an April 07, 2001 sandstorm over northern China, using MODIS. Results indicate that the area of the dust cloud observed was 1.34 million km2, the mean particle radius of the dust was 1.44 μm, and the mean optical depth at 11 μm was 0.79. The mean burden of dust was approximately 4.8 tons/km2 and the main portion of the dust storm on April 07, 2001 contained 6.5 million tons of dust. The results are supported by both independent remote sensing data (TOMS) and in situ data for a similar event in 1998. This paper demonstrates that Wen and Rose's retrieval method could be successfully applied to past and future sandstorm events using IR channels of AVHRR, GOES or MODIS.

African and Asian Dust: From Desert Soils to Coral Reefs

Abstract Many hypotheses have been proposed to explain the decline of coral reefs throughout the world, but none adequately accounts for the lack of recovery of reefs or the wide geographical distribution of coral diseases. The processes driving the decline remain elusive. Hundreds of millions of tons of dust transported annually from Africa and Asia to the Americas may be adversely affecting coral reefs and other downwind ecosystems. Viable microorganisms, macro- and micronutrients, trace metals, and an array of organic contaminants carried in the dust air masses and deposited in the oceans and on land may play important roles in the complex changes occurring on coral reefs worldwide.

Recycling of EAF dust into the EAF especially from high alloy steelmaking

In Europe about 600,000 tons of dusts are generated in EAF steelmaking. Valuable metals like zinc, lead, chromium and nickel are recovered from these dusts by external processors, usually. In the past, only few attempts on internal recycling have been made. Within a Brite EuRam II project, the economical and ecological benefits of the internal recycling of EAF dusts from engineering grades steelmaking have been documented. Recent investigations are dealing with the internal recycling of EAF dusts from high-alloy steeImaking, aiming at the recovery of chromium and nickel as well as at an improved foaming of the slag.

Aeolian behavior of dust in a simulated Martian environment

The behavior of aeolian dust, particles 1–2 microns (μm) in diameter, was analyzed in a simulated Martian environment. Three main areas have been investigated: (1) characterizing spectral and aeolian properties of Martian particles and natural wind‐blown terrestrial dust in order to identify a suitable surrogate Martian dust, (2) emplacement of the material in the simulated Martian environment, and (3) experimental procedures and testing in the Martian Surface Wind Tunnel (MARSWIT). The first phase of the study involved choosing a terrestrial dust that closely resembled Martian dust. Data accumulated from various sources suggest that Martian dust is derived from the weathering of basaltic parent material, nontronite clay being a good candidate composition. A commercial clay, Carbondale Red Clay (CRC), was determined to be an appropriate surrogate Martian dust. Using a compressed air‐dust ejection system, an air‐entrained dust cloud was generated which settled to cover the test section in the MARSWIT. This method best replicated the natural aerodynamic settling process presumed to exist on Mars. Low‐pressure experiments were performed in the MARSWIT facility located at the NASA Ames Research Center, Moffett Field, California. Two separate wind tunnel floors were used for these experiments; one provided an aerodynamically smooth‐surface flow, and the other was an aerodynamically rough‐surface flow. Initial and momentary particle movement was recorded at friction velocities as low as 2 m/s. However, the “dust” never reached fluid saltation threshold because individual particles less than 10 μm typically do not saltate, but pass into suspension. An estimated dust flux of 3.7×10−7 g/cm2 s was determined for a friction velocity of 2 m/s. This flux could suspend about 10,000 metric tons of dust per second over the surface of Mars. The dust behavior on the smooth surface was markedly different than on the rough surface under Martian conditions. Application of the processes described above to the Martian environment suggests that on rocky surfaces dust suspension would first occur, whereas smooth plains would require higher wind speeds for dust entrainment.

製鋼ダストからの製品亜鉛華の製造とその事業化について

Recovery of such valuable metals as zinc, lead and iron from steelmaking dust is, in other words, treatment of industrial wastes. The basic requirement in its implementaion is, therefore, not to generate another type of wastes from this operation.1. Using the St. Joe process, Toho Zinc Co., Ltd. had established the technology to recover zinc, in the from of zinc oxide, contained in leaching residues generated from electrolytic zinc refining. In this process, zinc is vaporized in the strong reduction atmosphere in the vertical electro-thermic furnace. The remarkable feature of this technology is that most of iron content in the clinker, which is generated from the process as final waste, is metallic and thus can be recycled as iron raw meterial.2. In the meantime, to manufacture chemical grade zinc oxide from steelmaking dust, it was necessary to combine the St. Joe process with an additional technology aimed to remove impurities.3. Theory of selective choridizing vaporization during the roasting process had been established as such additional technology, however, this theory had never been applied to manufacturing in any industrial scale. To implement the theory in the industrial scale, we conducted a fundamental test using a boat as well as two feasibility tests using rotary kilns with the dimensions of 0.43m.I.D.×10.8mL and 1.8m.I.D.×25mL, respectively. As a result of a series of tests, we concluded that the technolgy of selective chrolidizing roasting of lead, cadmium, etc. is feasible, and implemented the commercial production.4. Favorable results are being obtained in the oxidzing atmosphere at the temperature of 1100-1150°C in the rotary kiln with the dimension of 2.5m.I.D.×38mL. More than 95% of lead is vaporized and quality of zinc oxide produced is found satisfactorily stable.5. The chemical grade zinc oxide plant was installed in 1974 in the Onahama factory to treat steelmaking dust. The plant is currently treating approximately 50, 000-60, 000 tons of dust annually to produce 16, 000 tons of chemical grade zinc oxide per year.6. The above achievement is the result of renovation in our technology and rationalization at our plant over the past 22 years. We are committed to continuing steady efforts to make further progress in such areas as recovery and utilization of heat energy, the rate of recovery of valuable metals, and quality of the product.

曹鉄メタル（株）と日曹金属化学（株）における製鋼煙灰処理

Sotetsu Metal Co., Ltd. and Nisso Metallochemical Co., Ltd. started operation of Waelz plant for treatment of steel making dust in 1975. At present Sotetsu Metal Co., Ltd. treat 50, 000 tons of dust and recovery 17, 000 tons of crude zinc oxide annually. Nisso Metallochemical Co., Ltd. product high grade zinc oxide of 12, 000 tons and lead cake of 150 tons for smelting from crude zinc oxide.

Saharan dust in the Amazon Basin

Saharan dust is shown to enter the Central Amazon Basin (CAB) in bursts which accompany major wet season rain systems. Low-level horizontal convergence feeding these rain systems draws dust from plumes which have crossed the tropical Atlantic under the large-scale circulation fields. Mass exchange of air between the surface and 4 km over the eastern Amazon basin is calculated using rawinsonde data collected during storm events. Mean concentrations of dust observed by aircraft over the western tropical Atlantic are used to calculate the amount of dust injected into the Basin. Individual storm events inject some 480,000 tons of dust into the north-eastern Amazon Basin. Storm and dust climatology suggest that the annual importation of dust is in the order of 13 Mtons. In the north-eastern basin, this may amount to as much as 190 kg ha -1 yr -1 . Deposition of trace species, such as phosphate, associated with this dust ranges from 1-4 kg ha -1 yr -1 . Uncertainties in these estimates are not believed to be greater than ± 50% and may be as low as ± 20%. The deposition fluxes from Saharan dust are essentially identical to the CAB wet deposition fluxes from precipitation in the wet season; a result that implies that the major ionic composition of rain water in the CAB wet season may be strongly influenced by inputs of material originating on the African continent nearly 5000 km away. The total amount of Saharan dust calculated to enter the Amazon basin is 1/2 to 1/3 of that estimated to cross 60°W longitude between 10° and 25°N latitude. We conclude that part of the productivity of the Amazon rain forest is dependent upon critical trace elements contained in the soil dust originating in the Sahara/Sahel. This dependence should be reflected by expansions and contractions of the Amazon rain forest in direct relationship to expansions and contractions of the Sahara/Sahel. Turnover rates for nutrient species deposited with Saharan dust in the Amazon Basin suggest a time scale of 500 to 20,000 years. We believe the dependence of one large ecosystem upon another separated by an ocean and coupled by the atmosphere to be fundamentally important to any view of how the global system functions. Any strategy designed to preserve the Amazonian rain forest or any part thereof should equally concern itself with the inter-relationship between the rain forest, global climate and arid zones well removed from Amazonia. DOI: 10.1034/j.1600-0889.1992.t01-1-00005.x

Saharan dust and desert loess: effect on surrounding soils

Only specific desert environments are significant suppliers of the millions of tons of dust blown out annually from the Sahara to its fringes and across the seas. The major dustsource is weathered debris detrained by fluvial transport and redeposited on alluvial fans, in wadis and terminal basins. Rocky gravel and wet sebha surfaces are the only effective dust traps in the desert. Thick loess mantles accumulate on the fringes of the desert after medium or long distance transport where the rate of accretion exceeds 50 g m −2 per year over long a period. At lower deposition rates the dust becomes incorporated and assimilated by the local ground soil (or ocean sediment). Such additions have affected distant areas in southern Europe and Africa and have contributed to their fertility. More desert loess-derived or affected soils are likely to be recognized in the future.

Cometary origin of interplanetary submicron dust

view Abstract Citations (2) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cometary origin of interplanetary submicron dust. Parthasarathy, R. Abstract Biermann's (1967) suggestion that the submicron dust particles in the interplanetary medium may be of cometary origin is quantitatively pursued. With the aid of luminosity data pertaining to 46 long-period comets, it is found that long-period comets contribute 20 billion tons of dust of radius at least 0.0001 cm, per year, on average. If the emitted dust particles are fragile agglomerates of submicron grains that could eventually splinter, collisionally or otherwise, then the contribution is probably adequate to balance the loss rate of interplanetary submicron dust engendered by stochastic electrodynamic effects in the medium and sustain a quasi-steady-state concentration. The tentative nature of this conclusion is discussed. Publication: The Astronomical Journal Pub Date: January 1979 DOI: 10.1086/112401 Bibcode: 1979AJ.....84..143P Keywords: Interplanetary Dust; Interplanetary Medium; Microparticles; Comet Nuclei; Electrodynamics; Numerical Integration; Quasi-Steady States; COSMIC DUST; PARTICLES; SUBMICRON PARTICLES; COMETS; ECLIPTIC PLANE; ZODIACAL LIGHT; PHOTOELECTRIC EMISSIONS; ELECTRODYNAMICS; DENSITY; SOLAR WIND; CONCENTRATIONS; EMISSIONS; Astrophysics; Miscellaneous; Comets; Comets:Interplanetary Dust; Interplanetary Dust:Origin full text sources ADS |

The stratospheric dust event of October 1971

Since early 1970, color ratios of twilight photometry near Boston, Massachusetts, have indicated the return of stratospheric turbidity to normal conditions. However, rather strongly reddened twilights were recorded on October 1 and 17, 1971, and coarse, irregular striations were observed. From trajectories it may be presumed that the stratospheric dust observed on October 1 originated from a still unreported volcanic eruption along the rim of the northern Pacific Ocean. Later, the dust cloud was found to have moved over the southwestern United States before appearing over Boston again. Enhanced twilights and striations were observed until early 1972, when color ratios became very low, as is common in the spring season. The total stratospheric dust burden of the October event is estimated to have been 0.2 million metric tons, compared with the 2 million metric tons of dust in the northern hemisphere from the Agung eruption on Bali in 1963.